1/*-------------------------------------------------------------------------
2 *
3 * planner.c
4 * The query optimizer external interface.
5 *
6 * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
7 * Portions Copyright (c) 1994, Regents of the University of California
8 *
9 *
10 * IDENTIFICATION
11 * src/backend/optimizer/plan/planner.c
12 *
13 *-------------------------------------------------------------------------
14 */
15
16#include "postgres.h"
17
18#include <limits.h>
19#include <math.h>
20
21#include "access/genam.h"
22#include "access/htup_details.h"
23#include "access/parallel.h"
24#include "access/sysattr.h"
25#include "access/table.h"
26#include "access/xact.h"
27#include "catalog/pg_constraint.h"
28#include "catalog/pg_inherits.h"
29#include "catalog/pg_proc.h"
30#include "catalog/pg_type.h"
31#include "executor/executor.h"
32#include "executor/nodeAgg.h"
33#include "foreign/fdwapi.h"
34#include "miscadmin.h"
35#include "jit/jit.h"
36#include "lib/bipartite_match.h"
37#include "lib/knapsack.h"
38#include "nodes/makefuncs.h"
39#include "nodes/nodeFuncs.h"
40#ifdef OPTIMIZER_DEBUG
41#include "nodes/print.h"
42#endif
43#include "optimizer/appendinfo.h"
44#include "optimizer/clauses.h"
45#include "optimizer/cost.h"
46#include "optimizer/inherit.h"
47#include "optimizer/optimizer.h"
48#include "optimizer/paramassign.h"
49#include "optimizer/pathnode.h"
50#include "optimizer/paths.h"
51#include "optimizer/plancat.h"
52#include "optimizer/planmain.h"
53#include "optimizer/planner.h"
54#include "optimizer/prep.h"
55#include "optimizer/subselect.h"
56#include "optimizer/tlist.h"
57#include "parser/analyze.h"
58#include "parser/parsetree.h"
59#include "parser/parse_agg.h"
60#include "partitioning/partdesc.h"
61#include "rewrite/rewriteManip.h"
62#include "storage/dsm_impl.h"
63#include "utils/rel.h"
64#include "utils/selfuncs.h"
65#include "utils/lsyscache.h"
66#include "utils/syscache.h"
67
68
69/* GUC parameters */
70double cursor_tuple_fraction = DEFAULT_CURSOR_TUPLE_FRACTION;
71int force_parallel_mode = FORCE_PARALLEL_OFF;
72bool parallel_leader_participation = true;
73
74/* Hook for plugins to get control in planner() */
75planner_hook_type planner_hook = NULL;
76
77/* Hook for plugins to get control when grouping_planner() plans upper rels */
78create_upper_paths_hook_type create_upper_paths_hook = NULL;
79
80
81/* Expression kind codes for preprocess_expression */
82#define EXPRKIND_QUAL 0
83#define EXPRKIND_TARGET 1
84#define EXPRKIND_RTFUNC 2
85#define EXPRKIND_RTFUNC_LATERAL 3
86#define EXPRKIND_VALUES 4
87#define EXPRKIND_VALUES_LATERAL 5
88#define EXPRKIND_LIMIT 6
89#define EXPRKIND_APPINFO 7
90#define EXPRKIND_PHV 8
91#define EXPRKIND_TABLESAMPLE 9
92#define EXPRKIND_ARBITER_ELEM 10
93#define EXPRKIND_TABLEFUNC 11
94#define EXPRKIND_TABLEFUNC_LATERAL 12
95
96/* Passthrough data for standard_qp_callback */
97typedef struct
98{
99 List *activeWindows; /* active windows, if any */
100 List *groupClause; /* overrides parse->groupClause */
101} standard_qp_extra;
102
103/*
104 * Data specific to grouping sets
105 */
106
107typedef struct
108{
109 List *rollups;
110 List *hash_sets_idx;
111 double dNumHashGroups;
112 bool any_hashable;
113 Bitmapset *unsortable_refs;
114 Bitmapset *unhashable_refs;
115 List *unsortable_sets;
116 int *tleref_to_colnum_map;
117} grouping_sets_data;
118
119/*
120 * Temporary structure for use during WindowClause reordering in order to be
121 * able to sort WindowClauses on partitioning/ordering prefix.
122 */
123typedef struct
124{
125 WindowClause *wc;
126 List *uniqueOrder; /* A List of unique ordering/partitioning
127 * clauses per Window */
128} WindowClauseSortData;
129
130/* Local functions */
131static Node *preprocess_expression(PlannerInfo *root, Node *expr, int kind);
132static void preprocess_qual_conditions(PlannerInfo *root, Node *jtnode);
133static void inheritance_planner(PlannerInfo *root);
134static void grouping_planner(PlannerInfo *root, bool inheritance_update,
135 double tuple_fraction);
136static grouping_sets_data *preprocess_grouping_sets(PlannerInfo *root);
137static List *remap_to_groupclause_idx(List *groupClause, List *gsets,
138 int *tleref_to_colnum_map);
139static void preprocess_rowmarks(PlannerInfo *root);
140static double preprocess_limit(PlannerInfo *root,
141 double tuple_fraction,
142 int64 *offset_est, int64 *count_est);
143static void remove_useless_groupby_columns(PlannerInfo *root);
144static List *preprocess_groupclause(PlannerInfo *root, List *force);
145static List *extract_rollup_sets(List *groupingSets);
146static List *reorder_grouping_sets(List *groupingSets, List *sortclause);
147static void standard_qp_callback(PlannerInfo *root, void *extra);
148static double get_number_of_groups(PlannerInfo *root,
149 double path_rows,
150 grouping_sets_data *gd,
151 List *target_list);
152static RelOptInfo *create_grouping_paths(PlannerInfo *root,
153 RelOptInfo *input_rel,
154 PathTarget *target,
155 bool target_parallel_safe,
156 const AggClauseCosts *agg_costs,
157 grouping_sets_data *gd);
158static bool is_degenerate_grouping(PlannerInfo *root);
159static void create_degenerate_grouping_paths(PlannerInfo *root,
160 RelOptInfo *input_rel,
161 RelOptInfo *grouped_rel);
162static RelOptInfo *make_grouping_rel(PlannerInfo *root, RelOptInfo *input_rel,
163 PathTarget *target, bool target_parallel_safe,
164 Node *havingQual);
165static void create_ordinary_grouping_paths(PlannerInfo *root,
166 RelOptInfo *input_rel,
167 RelOptInfo *grouped_rel,
168 const AggClauseCosts *agg_costs,
169 grouping_sets_data *gd,
170 GroupPathExtraData *extra,
171 RelOptInfo **partially_grouped_rel_p);
172static void consider_groupingsets_paths(PlannerInfo *root,
173 RelOptInfo *grouped_rel,
174 Path *path,
175 bool is_sorted,
176 bool can_hash,
177 grouping_sets_data *gd,
178 const AggClauseCosts *agg_costs,
179 double dNumGroups);
180static RelOptInfo *create_window_paths(PlannerInfo *root,
181 RelOptInfo *input_rel,
182 PathTarget *input_target,
183 PathTarget *output_target,
184 bool output_target_parallel_safe,
185 WindowFuncLists *wflists,
186 List *activeWindows);
187static void create_one_window_path(PlannerInfo *root,
188 RelOptInfo *window_rel,
189 Path *path,
190 PathTarget *input_target,
191 PathTarget *output_target,
192 WindowFuncLists *wflists,
193 List *activeWindows);
194static RelOptInfo *create_distinct_paths(PlannerInfo *root,
195 RelOptInfo *input_rel);
196static RelOptInfo *create_ordered_paths(PlannerInfo *root,
197 RelOptInfo *input_rel,
198 PathTarget *target,
199 bool target_parallel_safe,
200 double limit_tuples);
201static PathTarget *make_group_input_target(PlannerInfo *root,
202 PathTarget *final_target);
203static PathTarget *make_partial_grouping_target(PlannerInfo *root,
204 PathTarget *grouping_target,
205 Node *havingQual);
206static List *postprocess_setop_tlist(List *new_tlist, List *orig_tlist);
207static List *select_active_windows(PlannerInfo *root, WindowFuncLists *wflists);
208static PathTarget *make_window_input_target(PlannerInfo *root,
209 PathTarget *final_target,
210 List *activeWindows);
211static List *make_pathkeys_for_window(PlannerInfo *root, WindowClause *wc,
212 List *tlist);
213static PathTarget *make_sort_input_target(PlannerInfo *root,
214 PathTarget *final_target,
215 bool *have_postponed_srfs);
216static void adjust_paths_for_srfs(PlannerInfo *root, RelOptInfo *rel,
217 List *targets, List *targets_contain_srfs);
218static void add_paths_to_grouping_rel(PlannerInfo *root, RelOptInfo *input_rel,
219 RelOptInfo *grouped_rel,
220 RelOptInfo *partially_grouped_rel,
221 const AggClauseCosts *agg_costs,
222 grouping_sets_data *gd,
223 double dNumGroups,
224 GroupPathExtraData *extra);
225static RelOptInfo *create_partial_grouping_paths(PlannerInfo *root,
226 RelOptInfo *grouped_rel,
227 RelOptInfo *input_rel,
228 grouping_sets_data *gd,
229 GroupPathExtraData *extra,
230 bool force_rel_creation);
231static void gather_grouping_paths(PlannerInfo *root, RelOptInfo *rel);
232static bool can_partial_agg(PlannerInfo *root,
233 const AggClauseCosts *agg_costs);
234static void apply_scanjoin_target_to_paths(PlannerInfo *root,
235 RelOptInfo *rel,
236 List *scanjoin_targets,
237 List *scanjoin_targets_contain_srfs,
238 bool scanjoin_target_parallel_safe,
239 bool tlist_same_exprs);
240static void create_partitionwise_grouping_paths(PlannerInfo *root,
241 RelOptInfo *input_rel,
242 RelOptInfo *grouped_rel,
243 RelOptInfo *partially_grouped_rel,
244 const AggClauseCosts *agg_costs,
245 grouping_sets_data *gd,
246 PartitionwiseAggregateType patype,
247 GroupPathExtraData *extra);
248static bool group_by_has_partkey(RelOptInfo *input_rel,
249 List *targetList,
250 List *groupClause);
251static int common_prefix_cmp(const void *a, const void *b);
252
253
254/*****************************************************************************
255 *
256 * Query optimizer entry point
257 *
258 * To support loadable plugins that monitor or modify planner behavior,
259 * we provide a hook variable that lets a plugin get control before and
260 * after the standard planning process. The plugin would normally call
261 * standard_planner().
262 *
263 * Note to plugin authors: standard_planner() scribbles on its Query input,
264 * so you'd better copy that data structure if you want to plan more than once.
265 *
266 *****************************************************************************/
267PlannedStmt *
268planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
269{
270 PlannedStmt *result;
271
272 if (planner_hook)
273 result = (*planner_hook) (parse, cursorOptions, boundParams);
274 else
275 result = standard_planner(parse, cursorOptions, boundParams);
276 return result;
277}
278
279PlannedStmt *
280standard_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
281{
282 PlannedStmt *result;
283 PlannerGlobal *glob;
284 double tuple_fraction;
285 PlannerInfo *root;
286 RelOptInfo *final_rel;
287 Path *best_path;
288 Plan *top_plan;
289 ListCell *lp,
290 *lr;
291
292 /*
293 * Set up global state for this planner invocation. This data is needed
294 * across all levels of sub-Query that might exist in the given command,
295 * so we keep it in a separate struct that's linked to by each per-Query
296 * PlannerInfo.
297 */
298 glob = makeNode(PlannerGlobal);
299
300 glob->boundParams = boundParams;
301 glob->subplans = NIL;
302 glob->subroots = NIL;
303 glob->rewindPlanIDs = NULL;
304 glob->finalrtable = NIL;
305 glob->finalrowmarks = NIL;
306 glob->resultRelations = NIL;
307 glob->rootResultRelations = NIL;
308 glob->relationOids = NIL;
309 glob->invalItems = NIL;
310 glob->paramExecTypes = NIL;
311 glob->lastPHId = 0;
312 glob->lastRowMarkId = 0;
313 glob->lastPlanNodeId = 0;
314 glob->transientPlan = false;
315 glob->dependsOnRole = false;
316
317 /*
318 * Assess whether it's feasible to use parallel mode for this query. We
319 * can't do this in a standalone backend, or if the command will try to
320 * modify any data, or if this is a cursor operation, or if GUCs are set
321 * to values that don't permit parallelism, or if parallel-unsafe
322 * functions are present in the query tree.
323 *
324 * (Note that we do allow CREATE TABLE AS, SELECT INTO, and CREATE
325 * MATERIALIZED VIEW to use parallel plans, but this is safe only because
326 * the command is writing into a completely new table which workers won't
327 * be able to see. If the workers could see the table, the fact that
328 * group locking would cause them to ignore the leader's heavyweight
329 * relation extension lock and GIN page locks would make this unsafe.
330 * We'll have to fix that somehow if we want to allow parallel inserts in
331 * general; updates and deletes have additional problems especially around
332 * combo CIDs.)
333 *
334 * For now, we don't try to use parallel mode if we're running inside a
335 * parallel worker. We might eventually be able to relax this
336 * restriction, but for now it seems best not to have parallel workers
337 * trying to create their own parallel workers.
338 */
339 if ((cursorOptions & CURSOR_OPT_PARALLEL_OK) != 0 &&
340 IsUnderPostmaster &&
341 parse->commandType == CMD_SELECT &&
342 !parse->hasModifyingCTE &&
343 max_parallel_workers_per_gather > 0 &&
344 !IsParallelWorker())
345 {
346 /* all the cheap tests pass, so scan the query tree */
347 glob->maxParallelHazard = max_parallel_hazard(parse);
348 glob->parallelModeOK = (glob->maxParallelHazard != PROPARALLEL_UNSAFE);
349 }
350 else
351 {
352 /* skip the query tree scan, just assume it's unsafe */
353 glob->maxParallelHazard = PROPARALLEL_UNSAFE;
354 glob->parallelModeOK = false;
355 }
356
357 /*
358 * glob->parallelModeNeeded is normally set to false here and changed to
359 * true during plan creation if a Gather or Gather Merge plan is actually
360 * created (cf. create_gather_plan, create_gather_merge_plan).
361 *
362 * However, if force_parallel_mode = on or force_parallel_mode = regress,
363 * then we impose parallel mode whenever it's safe to do so, even if the
364 * final plan doesn't use parallelism. It's not safe to do so if the
365 * query contains anything parallel-unsafe; parallelModeOK will be false
366 * in that case. Note that parallelModeOK can't change after this point.
367 * Otherwise, everything in the query is either parallel-safe or
368 * parallel-restricted, and in either case it should be OK to impose
369 * parallel-mode restrictions. If that ends up breaking something, then
370 * either some function the user included in the query is incorrectly
371 * labelled as parallel-safe or parallel-restricted when in reality it's
372 * parallel-unsafe, or else the query planner itself has a bug.
373 */
374 glob->parallelModeNeeded = glob->parallelModeOK &&
375 (force_parallel_mode != FORCE_PARALLEL_OFF);
376
377 /* Determine what fraction of the plan is likely to be scanned */
378 if (cursorOptions & CURSOR_OPT_FAST_PLAN)
379 {
380 /*
381 * We have no real idea how many tuples the user will ultimately FETCH
382 * from a cursor, but it is often the case that he doesn't want 'em
383 * all, or would prefer a fast-start plan anyway so that he can
384 * process some of the tuples sooner. Use a GUC parameter to decide
385 * what fraction to optimize for.
386 */
387 tuple_fraction = cursor_tuple_fraction;
388
389 /*
390 * We document cursor_tuple_fraction as simply being a fraction, which
391 * means the edge cases 0 and 1 have to be treated specially here. We
392 * convert 1 to 0 ("all the tuples") and 0 to a very small fraction.
393 */
394 if (tuple_fraction >= 1.0)
395 tuple_fraction = 0.0;
396 else if (tuple_fraction <= 0.0)
397 tuple_fraction = 1e-10;
398 }
399 else
400 {
401 /* Default assumption is we need all the tuples */
402 tuple_fraction = 0.0;
403 }
404
405 /* primary planning entry point (may recurse for subqueries) */
406 root = subquery_planner(glob, parse, NULL,
407 false, tuple_fraction);
408
409 /* Select best Path and turn it into a Plan */
410 final_rel = fetch_upper_rel(root, UPPERREL_FINAL, NULL);
411 best_path = get_cheapest_fractional_path(final_rel, tuple_fraction);
412
413 top_plan = create_plan(root, best_path);
414
415 /*
416 * If creating a plan for a scrollable cursor, make sure it can run
417 * backwards on demand. Add a Material node at the top at need.
418 */
419 if (cursorOptions & CURSOR_OPT_SCROLL)
420 {
421 if (!ExecSupportsBackwardScan(top_plan))
422 top_plan = materialize_finished_plan(top_plan);
423 }
424
425 /*
426 * Optionally add a Gather node for testing purposes, provided this is
427 * actually a safe thing to do.
428 */
429 if (force_parallel_mode != FORCE_PARALLEL_OFF && top_plan->parallel_safe)
430 {
431 Gather *gather = makeNode(Gather);
432
433 /*
434 * If there are any initPlans attached to the formerly-top plan node,
435 * move them up to the Gather node; same as we do for Material node in
436 * materialize_finished_plan.
437 */
438 gather->plan.initPlan = top_plan->initPlan;
439 top_plan->initPlan = NIL;
440
441 gather->plan.targetlist = top_plan->targetlist;
442 gather->plan.qual = NIL;
443 gather->plan.lefttree = top_plan;
444 gather->plan.righttree = NULL;
445 gather->num_workers = 1;
446 gather->single_copy = true;
447 gather->invisible = (force_parallel_mode == FORCE_PARALLEL_REGRESS);
448
449 /*
450 * Since this Gather has no parallel-aware descendants to signal to,
451 * we don't need a rescan Param.
452 */
453 gather->rescan_param = -1;
454
455 /*
456 * Ideally we'd use cost_gather here, but setting up dummy path data
457 * to satisfy it doesn't seem much cleaner than knowing what it does.
458 */
459 gather->plan.startup_cost = top_plan->startup_cost +
460 parallel_setup_cost;
461 gather->plan.total_cost = top_plan->total_cost +
462 parallel_setup_cost + parallel_tuple_cost * top_plan->plan_rows;
463 gather->plan.plan_rows = top_plan->plan_rows;
464 gather->plan.plan_width = top_plan->plan_width;
465 gather->plan.parallel_aware = false;
466 gather->plan.parallel_safe = false;
467
468 /* use parallel mode for parallel plans. */
469 root->glob->parallelModeNeeded = true;
470
471 top_plan = &gather->plan;
472 }
473
474 /*
475 * If any Params were generated, run through the plan tree and compute
476 * each plan node's extParam/allParam sets. Ideally we'd merge this into
477 * set_plan_references' tree traversal, but for now it has to be separate
478 * because we need to visit subplans before not after main plan.
479 */
480 if (glob->paramExecTypes != NIL)
481 {
482 Assert(list_length(glob->subplans) == list_length(glob->subroots));
483 forboth(lp, glob->subplans, lr, glob->subroots)
484 {
485 Plan *subplan = (Plan *) lfirst(lp);
486 PlannerInfo *subroot = lfirst_node(PlannerInfo, lr);
487
488 SS_finalize_plan(subroot, subplan);
489 }
490 SS_finalize_plan(root, top_plan);
491 }
492
493 /* final cleanup of the plan */
494 Assert(glob->finalrtable == NIL);
495 Assert(glob->finalrowmarks == NIL);
496 Assert(glob->resultRelations == NIL);
497 Assert(glob->rootResultRelations == NIL);
498 top_plan = set_plan_references(root, top_plan);
499 /* ... and the subplans (both regular subplans and initplans) */
500 Assert(list_length(glob->subplans) == list_length(glob->subroots));
501 forboth(lp, glob->subplans, lr, glob->subroots)
502 {
503 Plan *subplan = (Plan *) lfirst(lp);
504 PlannerInfo *subroot = lfirst_node(PlannerInfo, lr);
505
506 lfirst(lp) = set_plan_references(subroot, subplan);
507 }
508
509 /* build the PlannedStmt result */
510 result = makeNode(PlannedStmt);
511
512 result->commandType = parse->commandType;
513 result->queryId = parse->queryId;
514 result->hasReturning = (parse->returningList != NIL);
515 result->hasModifyingCTE = parse->hasModifyingCTE;
516 result->canSetTag = parse->canSetTag;
517 result->transientPlan = glob->transientPlan;
518 result->dependsOnRole = glob->dependsOnRole;
519 result->parallelModeNeeded = glob->parallelModeNeeded;
520 result->planTree = top_plan;
521 result->rtable = glob->finalrtable;
522 result->resultRelations = glob->resultRelations;
523 result->rootResultRelations = glob->rootResultRelations;
524 result->subplans = glob->subplans;
525 result->rewindPlanIDs = glob->rewindPlanIDs;
526 result->rowMarks = glob->finalrowmarks;
527 result->relationOids = glob->relationOids;
528 result->invalItems = glob->invalItems;
529 result->paramExecTypes = glob->paramExecTypes;
530 /* utilityStmt should be null, but we might as well copy it */
531 result->utilityStmt = parse->utilityStmt;
532 result->stmt_location = parse->stmt_location;
533 result->stmt_len = parse->stmt_len;
534
535 result->jitFlags = PGJIT_NONE;
536 if (jit_enabled && jit_above_cost >= 0 &&
537 top_plan->total_cost > jit_above_cost)
538 {
539 result->jitFlags |= PGJIT_PERFORM;
540
541 /*
542 * Decide how much effort should be put into generating better code.
543 */
544 if (jit_optimize_above_cost >= 0 &&
545 top_plan->total_cost > jit_optimize_above_cost)
546 result->jitFlags |= PGJIT_OPT3;
547 if (jit_inline_above_cost >= 0 &&
548 top_plan->total_cost > jit_inline_above_cost)
549 result->jitFlags |= PGJIT_INLINE;
550
551 /*
552 * Decide which operations should be JITed.
553 */
554 if (jit_expressions)
555 result->jitFlags |= PGJIT_EXPR;
556 if (jit_tuple_deforming)
557 result->jitFlags |= PGJIT_DEFORM;
558 }
559
560 if (glob->partition_directory != NULL)
561 DestroyPartitionDirectory(glob->partition_directory);
562
563 return result;
564}
565
566
567/*--------------------
568 * subquery_planner
569 * Invokes the planner on a subquery. We recurse to here for each
570 * sub-SELECT found in the query tree.
571 *
572 * glob is the global state for the current planner run.
573 * parse is the querytree produced by the parser & rewriter.
574 * parent_root is the immediate parent Query's info (NULL at the top level).
575 * hasRecursion is true if this is a recursive WITH query.
576 * tuple_fraction is the fraction of tuples we expect will be retrieved.
577 * tuple_fraction is interpreted as explained for grouping_planner, below.
578 *
579 * Basically, this routine does the stuff that should only be done once
580 * per Query object. It then calls grouping_planner. At one time,
581 * grouping_planner could be invoked recursively on the same Query object;
582 * that's not currently true, but we keep the separation between the two
583 * routines anyway, in case we need it again someday.
584 *
585 * subquery_planner will be called recursively to handle sub-Query nodes
586 * found within the query's expressions and rangetable.
587 *
588 * Returns the PlannerInfo struct ("root") that contains all data generated
589 * while planning the subquery. In particular, the Path(s) attached to
590 * the (UPPERREL_FINAL, NULL) upperrel represent our conclusions about the
591 * cheapest way(s) to implement the query. The top level will select the
592 * best Path and pass it through createplan.c to produce a finished Plan.
593 *--------------------
594 */
595PlannerInfo *
596subquery_planner(PlannerGlobal *glob, Query *parse,
597 PlannerInfo *parent_root,
598 bool hasRecursion, double tuple_fraction)
599{
600 PlannerInfo *root;
601 List *newWithCheckOptions;
602 List *newHaving;
603 bool hasOuterJoins;
604 bool hasResultRTEs;
605 RelOptInfo *final_rel;
606 ListCell *l;
607
608 /* Create a PlannerInfo data structure for this subquery */
609 root = makeNode(PlannerInfo);
610 root->parse = parse;
611 root->glob = glob;
612 root->query_level = parent_root ? parent_root->query_level + 1 : 1;
613 root->parent_root = parent_root;
614 root->plan_params = NIL;
615 root->outer_params = NULL;
616 root->planner_cxt = CurrentMemoryContext;
617 root->init_plans = NIL;
618 root->cte_plan_ids = NIL;
619 root->multiexpr_params = NIL;
620 root->eq_classes = NIL;
621 root->append_rel_list = NIL;
622 root->rowMarks = NIL;
623 memset(root->upper_rels, 0, sizeof(root->upper_rels));
624 memset(root->upper_targets, 0, sizeof(root->upper_targets));
625 root->processed_tlist = NIL;
626 root->grouping_map = NULL;
627 root->minmax_aggs = NIL;
628 root->qual_security_level = 0;
629 root->inhTargetKind = INHKIND_NONE;
630 root->hasRecursion = hasRecursion;
631 if (hasRecursion)
632 root->wt_param_id = assign_special_exec_param(root);
633 else
634 root->wt_param_id = -1;
635 root->non_recursive_path = NULL;
636 root->partColsUpdated = false;
637
638 /*
639 * If there is a WITH list, process each WITH query and either convert it
640 * to RTE_SUBQUERY RTE(s) or build an initplan SubPlan structure for it.
641 */
642 if (parse->cteList)
643 SS_process_ctes(root);
644
645 /*
646 * If the FROM clause is empty, replace it with a dummy RTE_RESULT RTE, so
647 * that we don't need so many special cases to deal with that situation.
648 */
649 replace_empty_jointree(parse);
650
651 /*
652 * Look for ANY and EXISTS SubLinks in WHERE and JOIN/ON clauses, and try
653 * to transform them into joins. Note that this step does not descend
654 * into subqueries; if we pull up any subqueries below, their SubLinks are
655 * processed just before pulling them up.
656 */
657 if (parse->hasSubLinks)
658 pull_up_sublinks(root);
659
660 /*
661 * Scan the rangetable for set-returning functions, and inline them if
662 * possible (producing subqueries that might get pulled up next).
663 * Recursion issues here are handled in the same way as for SubLinks.
664 */
665 inline_set_returning_functions(root);
666
667 /*
668 * Check to see if any subqueries in the jointree can be merged into this
669 * query.
670 */
671 pull_up_subqueries(root);
672
673 /*
674 * If this is a simple UNION ALL query, flatten it into an appendrel. We
675 * do this now because it requires applying pull_up_subqueries to the leaf
676 * queries of the UNION ALL, which weren't touched above because they
677 * weren't referenced by the jointree (they will be after we do this).
678 */
679 if (parse->setOperations)
680 flatten_simple_union_all(root);
681
682 /*
683 * Survey the rangetable to see what kinds of entries are present. We can
684 * skip some later processing if relevant SQL features are not used; for
685 * example if there are no JOIN RTEs we can avoid the expense of doing
686 * flatten_join_alias_vars(). This must be done after we have finished
687 * adding rangetable entries, of course. (Note: actually, processing of
688 * inherited or partitioned rels can cause RTEs for their child tables to
689 * get added later; but those must all be RTE_RELATION entries, so they
690 * don't invalidate the conclusions drawn here.)
691 */
692 root->hasJoinRTEs = false;
693 root->hasLateralRTEs = false;
694 hasOuterJoins = false;
695 hasResultRTEs = false;
696 foreach(l, parse->rtable)
697 {
698 RangeTblEntry *rte = lfirst_node(RangeTblEntry, l);
699
700 switch (rte->rtekind)
701 {
702 case RTE_RELATION:
703 if (rte->inh)
704 {
705 /*
706 * Check to see if the relation actually has any children;
707 * if not, clear the inh flag so we can treat it as a
708 * plain base relation.
709 *
710 * Note: this could give a false-positive result, if the
711 * rel once had children but no longer does. We used to
712 * be able to clear rte->inh later on when we discovered
713 * that, but no more; we have to handle such cases as
714 * full-fledged inheritance.
715 */
716 rte->inh = has_subclass(rte->relid);
717 }
718 break;
719 case RTE_JOIN:
720 root->hasJoinRTEs = true;
721 if (IS_OUTER_JOIN(rte->jointype))
722 hasOuterJoins = true;
723 break;
724 case RTE_RESULT:
725 hasResultRTEs = true;
726 break;
727 default:
728 /* No work here for other RTE types */
729 break;
730 }
731
732 if (rte->lateral)
733 root->hasLateralRTEs = true;
734
735 /*
736 * We can also determine the maximum security level required for any
737 * securityQuals now. Addition of inheritance-child RTEs won't affect
738 * this, because child tables don't have their own securityQuals; see
739 * expand_single_inheritance_child().
740 */
741 if (rte->securityQuals)
742 root->qual_security_level = Max(root->qual_security_level,
743 list_length(rte->securityQuals));
744 }
745
746 /*
747 * Preprocess RowMark information. We need to do this after subquery
748 * pullup, so that all base relations are present.
749 */
750 preprocess_rowmarks(root);
751
752 /*
753 * Set hasHavingQual to remember if HAVING clause is present. Needed
754 * because preprocess_expression will reduce a constant-true condition to
755 * an empty qual list ... but "HAVING TRUE" is not a semantic no-op.
756 */
757 root->hasHavingQual = (parse->havingQual != NULL);
758
759 /* Clear this flag; might get set in distribute_qual_to_rels */
760 root->hasPseudoConstantQuals = false;
761
762 /*
763 * Do expression preprocessing on targetlist and quals, as well as other
764 * random expressions in the querytree. Note that we do not need to
765 * handle sort/group expressions explicitly, because they are actually
766 * part of the targetlist.
767 */
768 parse->targetList = (List *)
769 preprocess_expression(root, (Node *) parse->targetList,
770 EXPRKIND_TARGET);
771
772 /* Constant-folding might have removed all set-returning functions */
773 if (parse->hasTargetSRFs)
774 parse->hasTargetSRFs = expression_returns_set((Node *) parse->targetList);
775
776 newWithCheckOptions = NIL;
777 foreach(l, parse->withCheckOptions)
778 {
779 WithCheckOption *wco = lfirst_node(WithCheckOption, l);
780
781 wco->qual = preprocess_expression(root, wco->qual,
782 EXPRKIND_QUAL);
783 if (wco->qual != NULL)
784 newWithCheckOptions = lappend(newWithCheckOptions, wco);
785 }
786 parse->withCheckOptions = newWithCheckOptions;
787
788 parse->returningList = (List *)
789 preprocess_expression(root, (Node *) parse->returningList,
790 EXPRKIND_TARGET);
791
792 preprocess_qual_conditions(root, (Node *) parse->jointree);
793
794 parse->havingQual = preprocess_expression(root, parse->havingQual,
795 EXPRKIND_QUAL);
796
797 foreach(l, parse->windowClause)
798 {
799 WindowClause *wc = lfirst_node(WindowClause, l);
800
801 /* partitionClause/orderClause are sort/group expressions */
802 wc->startOffset = preprocess_expression(root, wc->startOffset,
803 EXPRKIND_LIMIT);
804 wc->endOffset = preprocess_expression(root, wc->endOffset,
805 EXPRKIND_LIMIT);
806 }
807
808 parse->limitOffset = preprocess_expression(root, parse->limitOffset,
809 EXPRKIND_LIMIT);
810 parse->limitCount = preprocess_expression(root, parse->limitCount,
811 EXPRKIND_LIMIT);
812
813 if (parse->onConflict)
814 {
815 parse->onConflict->arbiterElems = (List *)
816 preprocess_expression(root,
817 (Node *) parse->onConflict->arbiterElems,
818 EXPRKIND_ARBITER_ELEM);
819 parse->onConflict->arbiterWhere =
820 preprocess_expression(root,
821 parse->onConflict->arbiterWhere,
822 EXPRKIND_QUAL);
823 parse->onConflict->onConflictSet = (List *)
824 preprocess_expression(root,
825 (Node *) parse->onConflict->onConflictSet,
826 EXPRKIND_TARGET);
827 parse->onConflict->onConflictWhere =
828 preprocess_expression(root,
829 parse->onConflict->onConflictWhere,
830 EXPRKIND_QUAL);
831 /* exclRelTlist contains only Vars, so no preprocessing needed */
832 }
833
834 root->append_rel_list = (List *)
835 preprocess_expression(root, (Node *) root->append_rel_list,
836 EXPRKIND_APPINFO);
837
838 /* Also need to preprocess expressions within RTEs */
839 foreach(l, parse->rtable)
840 {
841 RangeTblEntry *rte = lfirst_node(RangeTblEntry, l);
842 int kind;
843 ListCell *lcsq;
844
845 if (rte->rtekind == RTE_RELATION)
846 {
847 if (rte->tablesample)
848 rte->tablesample = (TableSampleClause *)
849 preprocess_expression(root,
850 (Node *) rte->tablesample,
851 EXPRKIND_TABLESAMPLE);
852 }
853 else if (rte->rtekind == RTE_SUBQUERY)
854 {
855 /*
856 * We don't want to do all preprocessing yet on the subquery's
857 * expressions, since that will happen when we plan it. But if it
858 * contains any join aliases of our level, those have to get
859 * expanded now, because planning of the subquery won't do it.
860 * That's only possible if the subquery is LATERAL.
861 */
862 if (rte->lateral && root->hasJoinRTEs)
863 rte->subquery = (Query *)
864 flatten_join_alias_vars(root->parse,
865 (Node *) rte->subquery);
866 }
867 else if (rte->rtekind == RTE_FUNCTION)
868 {
869 /* Preprocess the function expression(s) fully */
870 kind = rte->lateral ? EXPRKIND_RTFUNC_LATERAL : EXPRKIND_RTFUNC;
871 rte->functions = (List *)
872 preprocess_expression(root, (Node *) rte->functions, kind);
873 }
874 else if (rte->rtekind == RTE_TABLEFUNC)
875 {
876 /* Preprocess the function expression(s) fully */
877 kind = rte->lateral ? EXPRKIND_TABLEFUNC_LATERAL : EXPRKIND_TABLEFUNC;
878 rte->tablefunc = (TableFunc *)
879 preprocess_expression(root, (Node *) rte->tablefunc, kind);
880 }
881 else if (rte->rtekind == RTE_VALUES)
882 {
883 /* Preprocess the values lists fully */
884 kind = rte->lateral ? EXPRKIND_VALUES_LATERAL : EXPRKIND_VALUES;
885 rte->values_lists = (List *)
886 preprocess_expression(root, (Node *) rte->values_lists, kind);
887 }
888
889 /*
890 * Process each element of the securityQuals list as if it were a
891 * separate qual expression (as indeed it is). We need to do it this
892 * way to get proper canonicalization of AND/OR structure. Note that
893 * this converts each element into an implicit-AND sublist.
894 */
895 foreach(lcsq, rte->securityQuals)
896 {
897 lfirst(lcsq) = preprocess_expression(root,
898 (Node *) lfirst(lcsq),
899 EXPRKIND_QUAL);
900 }
901 }
902
903 /*
904 * Now that we are done preprocessing expressions, and in particular done
905 * flattening join alias variables, get rid of the joinaliasvars lists.
906 * They no longer match what expressions in the rest of the tree look
907 * like, because we have not preprocessed expressions in those lists (and
908 * do not want to; for example, expanding a SubLink there would result in
909 * a useless unreferenced subplan). Leaving them in place simply creates
910 * a hazard for later scans of the tree. We could try to prevent that by
911 * using QTW_IGNORE_JOINALIASES in every tree scan done after this point,
912 * but that doesn't sound very reliable.
913 */
914 if (root->hasJoinRTEs)
915 {
916 foreach(l, parse->rtable)
917 {
918 RangeTblEntry *rte = lfirst_node(RangeTblEntry, l);
919
920 rte->joinaliasvars = NIL;
921 }
922 }
923
924 /*
925 * In some cases we may want to transfer a HAVING clause into WHERE. We
926 * cannot do so if the HAVING clause contains aggregates (obviously) or
927 * volatile functions (since a HAVING clause is supposed to be executed
928 * only once per group). We also can't do this if there are any nonempty
929 * grouping sets; moving such a clause into WHERE would potentially change
930 * the results, if any referenced column isn't present in all the grouping
931 * sets. (If there are only empty grouping sets, then the HAVING clause
932 * must be degenerate as discussed below.)
933 *
934 * Also, it may be that the clause is so expensive to execute that we're
935 * better off doing it only once per group, despite the loss of
936 * selectivity. This is hard to estimate short of doing the entire
937 * planning process twice, so we use a heuristic: clauses containing
938 * subplans are left in HAVING. Otherwise, we move or copy the HAVING
939 * clause into WHERE, in hopes of eliminating tuples before aggregation
940 * instead of after.
941 *
942 * If the query has explicit grouping then we can simply move such a
943 * clause into WHERE; any group that fails the clause will not be in the
944 * output because none of its tuples will reach the grouping or
945 * aggregation stage. Otherwise we must have a degenerate (variable-free)
946 * HAVING clause, which we put in WHERE so that query_planner() can use it
947 * in a gating Result node, but also keep in HAVING to ensure that we
948 * don't emit a bogus aggregated row. (This could be done better, but it
949 * seems not worth optimizing.)
950 *
951 * Note that both havingQual and parse->jointree->quals are in
952 * implicitly-ANDed-list form at this point, even though they are declared
953 * as Node *.
954 */
955 newHaving = NIL;
956 foreach(l, (List *) parse->havingQual)
957 {
958 Node *havingclause = (Node *) lfirst(l);
959
960 if ((parse->groupClause && parse->groupingSets) ||
961 contain_agg_clause(havingclause) ||
962 contain_volatile_functions(havingclause) ||
963 contain_subplans(havingclause))
964 {
965 /* keep it in HAVING */
966 newHaving = lappend(newHaving, havingclause);
967 }
968 else if (parse->groupClause && !parse->groupingSets)
969 {
970 /* move it to WHERE */
971 parse->jointree->quals = (Node *)
972 lappend((List *) parse->jointree->quals, havingclause);
973 }
974 else
975 {
976 /* put a copy in WHERE, keep it in HAVING */
977 parse->jointree->quals = (Node *)
978 lappend((List *) parse->jointree->quals,
979 copyObject(havingclause));
980 newHaving = lappend(newHaving, havingclause);
981 }
982 }
983 parse->havingQual = (Node *) newHaving;
984
985 /* Remove any redundant GROUP BY columns */
986 remove_useless_groupby_columns(root);
987
988 /*
989 * If we have any outer joins, try to reduce them to plain inner joins.
990 * This step is most easily done after we've done expression
991 * preprocessing.
992 */
993 if (hasOuterJoins)
994 reduce_outer_joins(root);
995
996 /*
997 * If we have any RTE_RESULT relations, see if they can be deleted from
998 * the jointree. This step is most effectively done after we've done
999 * expression preprocessing and outer join reduction.
1000 */
1001 if (hasResultRTEs)
1002 remove_useless_result_rtes(root);
1003
1004 /*
1005 * Do the main planning. If we have an inherited target relation, that
1006 * needs special processing, else go straight to grouping_planner.
1007 */
1008 if (parse->resultRelation &&
1009 rt_fetch(parse->resultRelation, parse->rtable)->inh)
1010 inheritance_planner(root);
1011 else
1012 grouping_planner(root, false, tuple_fraction);
1013
1014 /*
1015 * Capture the set of outer-level param IDs we have access to, for use in
1016 * extParam/allParam calculations later.
1017 */
1018 SS_identify_outer_params(root);
1019
1020 /*
1021 * If any initPlans were created in this query level, adjust the surviving
1022 * Paths' costs and parallel-safety flags to account for them. The
1023 * initPlans won't actually get attached to the plan tree till
1024 * create_plan() runs, but we must include their effects now.
1025 */
1026 final_rel = fetch_upper_rel(root, UPPERREL_FINAL, NULL);
1027 SS_charge_for_initplans(root, final_rel);
1028
1029 /*
1030 * Make sure we've identified the cheapest Path for the final rel. (By
1031 * doing this here not in grouping_planner, we include initPlan costs in
1032 * the decision, though it's unlikely that will change anything.)
1033 */
1034 set_cheapest(final_rel);
1035
1036 return root;
1037}
1038
1039/*
1040 * preprocess_expression
1041 * Do subquery_planner's preprocessing work for an expression,
1042 * which can be a targetlist, a WHERE clause (including JOIN/ON
1043 * conditions), a HAVING clause, or a few other things.
1044 */
1045static Node *
1046preprocess_expression(PlannerInfo *root, Node *expr, int kind)
1047{
1048 /*
1049 * Fall out quickly if expression is empty. This occurs often enough to
1050 * be worth checking. Note that null->null is the correct conversion for
1051 * implicit-AND result format, too.
1052 */
1053 if (expr == NULL)
1054 return NULL;
1055
1056 /*
1057 * If the query has any join RTEs, replace join alias variables with
1058 * base-relation variables. We must do this first, since any expressions
1059 * we may extract from the joinaliasvars lists have not been preprocessed.
1060 * For example, if we did this after sublink processing, sublinks expanded
1061 * out from join aliases would not get processed. But we can skip this in
1062 * non-lateral RTE functions, VALUES lists, and TABLESAMPLE clauses, since
1063 * they can't contain any Vars of the current query level.
1064 */
1065 if (root->hasJoinRTEs &&
1066 !(kind == EXPRKIND_RTFUNC ||
1067 kind == EXPRKIND_VALUES ||
1068 kind == EXPRKIND_TABLESAMPLE ||
1069 kind == EXPRKIND_TABLEFUNC))
1070 expr = flatten_join_alias_vars(root->parse, expr);
1071
1072 /*
1073 * Simplify constant expressions.
1074 *
1075 * Note: an essential effect of this is to convert named-argument function
1076 * calls to positional notation and insert the current actual values of
1077 * any default arguments for functions. To ensure that happens, we *must*
1078 * process all expressions here. Previous PG versions sometimes skipped
1079 * const-simplification if it didn't seem worth the trouble, but we can't
1080 * do that anymore.
1081 *
1082 * Note: this also flattens nested AND and OR expressions into N-argument
1083 * form. All processing of a qual expression after this point must be
1084 * careful to maintain AND/OR flatness --- that is, do not generate a tree
1085 * with AND directly under AND, nor OR directly under OR.
1086 */
1087 expr = eval_const_expressions(root, expr);
1088
1089 /*
1090 * If it's a qual or havingQual, canonicalize it.
1091 */
1092 if (kind == EXPRKIND_QUAL)
1093 {
1094 expr = (Node *) canonicalize_qual((Expr *) expr, false);
1095
1096#ifdef OPTIMIZER_DEBUG
1097 printf("After canonicalize_qual()\n");
1098 pprint(expr);
1099#endif
1100 }
1101
1102 /* Expand SubLinks to SubPlans */
1103 if (root->parse->hasSubLinks)
1104 expr = SS_process_sublinks(root, expr, (kind == EXPRKIND_QUAL));
1105
1106 /*
1107 * XXX do not insert anything here unless you have grokked the comments in
1108 * SS_replace_correlation_vars ...
1109 */
1110
1111 /* Replace uplevel vars with Param nodes (this IS possible in VALUES) */
1112 if (root->query_level > 1)
1113 expr = SS_replace_correlation_vars(root, expr);
1114
1115 /*
1116 * If it's a qual or havingQual, convert it to implicit-AND format. (We
1117 * don't want to do this before eval_const_expressions, since the latter
1118 * would be unable to simplify a top-level AND correctly. Also,
1119 * SS_process_sublinks expects explicit-AND format.)
1120 */
1121 if (kind == EXPRKIND_QUAL)
1122 expr = (Node *) make_ands_implicit((Expr *) expr);
1123
1124 return expr;
1125}
1126
1127/*
1128 * preprocess_qual_conditions
1129 * Recursively scan the query's jointree and do subquery_planner's
1130 * preprocessing work on each qual condition found therein.
1131 */
1132static void
1133preprocess_qual_conditions(PlannerInfo *root, Node *jtnode)
1134{
1135 if (jtnode == NULL)
1136 return;
1137 if (IsA(jtnode, RangeTblRef))
1138 {
1139 /* nothing to do here */
1140 }
1141 else if (IsA(jtnode, FromExpr))
1142 {
1143 FromExpr *f = (FromExpr *) jtnode;
1144 ListCell *l;
1145
1146 foreach(l, f->fromlist)
1147 preprocess_qual_conditions(root, lfirst(l));
1148
1149 f->quals = preprocess_expression(root, f->quals, EXPRKIND_QUAL);
1150 }
1151 else if (IsA(jtnode, JoinExpr))
1152 {
1153 JoinExpr *j = (JoinExpr *) jtnode;
1154
1155 preprocess_qual_conditions(root, j->larg);
1156 preprocess_qual_conditions(root, j->rarg);
1157
1158 j->quals = preprocess_expression(root, j->quals, EXPRKIND_QUAL);
1159 }
1160 else
1161 elog(ERROR, "unrecognized node type: %d",
1162 (int) nodeTag(jtnode));
1163}
1164
1165/*
1166 * preprocess_phv_expression
1167 * Do preprocessing on a PlaceHolderVar expression that's been pulled up.
1168 *
1169 * If a LATERAL subquery references an output of another subquery, and that
1170 * output must be wrapped in a PlaceHolderVar because of an intermediate outer
1171 * join, then we'll push the PlaceHolderVar expression down into the subquery
1172 * and later pull it back up during find_lateral_references, which runs after
1173 * subquery_planner has preprocessed all the expressions that were in the
1174 * current query level to start with. So we need to preprocess it then.
1175 */
1176Expr *
1177preprocess_phv_expression(PlannerInfo *root, Expr *expr)
1178{
1179 return (Expr *) preprocess_expression(root, (Node *) expr, EXPRKIND_PHV);
1180}
1181
1182/*
1183 * inheritance_planner
1184 * Generate Paths in the case where the result relation is an
1185 * inheritance set.
1186 *
1187 * We have to handle this case differently from cases where a source relation
1188 * is an inheritance set. Source inheritance is expanded at the bottom of the
1189 * plan tree (see allpaths.c), but target inheritance has to be expanded at
1190 * the top. The reason is that for UPDATE, each target relation needs a
1191 * different targetlist matching its own column set. Fortunately,
1192 * the UPDATE/DELETE target can never be the nullable side of an outer join,
1193 * so it's OK to generate the plan this way.
1194 *
1195 * Returns nothing; the useful output is in the Paths we attach to
1196 * the (UPPERREL_FINAL, NULL) upperrel stored in *root.
1197 *
1198 * Note that we have not done set_cheapest() on the final rel; it's convenient
1199 * to leave this to the caller.
1200 */
1201static void
1202inheritance_planner(PlannerInfo *root)
1203{
1204 Query *parse = root->parse;
1205 int top_parentRTindex = parse->resultRelation;
1206 List *select_rtable;
1207 List *select_appinfos;
1208 List *child_appinfos;
1209 List *old_child_rtis;
1210 List *new_child_rtis;
1211 Bitmapset *subqueryRTindexes;
1212 Index next_subquery_rti;
1213 int nominalRelation = -1;
1214 Index rootRelation = 0;
1215 List *final_rtable = NIL;
1216 List *final_rowmarks = NIL;
1217 int save_rel_array_size = 0;
1218 RelOptInfo **save_rel_array = NULL;
1219 AppendRelInfo **save_append_rel_array = NULL;
1220 List *subpaths = NIL;
1221 List *subroots = NIL;
1222 List *resultRelations = NIL;
1223 List *withCheckOptionLists = NIL;
1224 List *returningLists = NIL;
1225 List *rowMarks;
1226 RelOptInfo *final_rel;
1227 ListCell *lc;
1228 ListCell *lc2;
1229 Index rti;
1230 RangeTblEntry *parent_rte;
1231 Bitmapset *parent_relids;
1232 Query **parent_parses;
1233
1234 /* Should only get here for UPDATE or DELETE */
1235 Assert(parse->commandType == CMD_UPDATE ||
1236 parse->commandType == CMD_DELETE);
1237
1238 /*
1239 * We generate a modified instance of the original Query for each target
1240 * relation, plan that, and put all the plans into a list that will be
1241 * controlled by a single ModifyTable node. All the instances share the
1242 * same rangetable, but each instance must have its own set of subquery
1243 * RTEs within the finished rangetable because (1) they are likely to get
1244 * scribbled on during planning, and (2) it's not inconceivable that
1245 * subqueries could get planned differently in different cases. We need
1246 * not create duplicate copies of other RTE kinds, in particular not the
1247 * target relations, because they don't have either of those issues. Not
1248 * having to duplicate the target relations is important because doing so
1249 * (1) would result in a rangetable of length O(N^2) for N targets, with
1250 * at least O(N^3) work expended here; and (2) would greatly complicate
1251 * management of the rowMarks list.
1252 *
1253 * To begin with, generate a bitmapset of the relids of the subquery RTEs.
1254 */
1255 subqueryRTindexes = NULL;
1256 rti = 1;
1257 foreach(lc, parse->rtable)
1258 {
1259 RangeTblEntry *rte = lfirst_node(RangeTblEntry, lc);
1260
1261 if (rte->rtekind == RTE_SUBQUERY)
1262 subqueryRTindexes = bms_add_member(subqueryRTindexes, rti);
1263 rti++;
1264 }
1265
1266 /*
1267 * If the parent RTE is a partitioned table, we should use that as the
1268 * nominal target relation, because the RTEs added for partitioned tables
1269 * (including the root parent) as child members of the inheritance set do
1270 * not appear anywhere else in the plan, so the confusion explained below
1271 * for non-partitioning inheritance cases is not possible.
1272 */
1273 parent_rte = rt_fetch(top_parentRTindex, parse->rtable);
1274 Assert(parent_rte->inh);
1275 if (parent_rte->relkind == RELKIND_PARTITIONED_TABLE)
1276 {
1277 nominalRelation = top_parentRTindex;
1278 rootRelation = top_parentRTindex;
1279 }
1280
1281 /*
1282 * Before generating the real per-child-relation plans, do a cycle of
1283 * planning as though the query were a SELECT. The objective here is to
1284 * find out which child relations need to be processed, using the same
1285 * expansion and pruning logic as for a SELECT. We'll then pull out the
1286 * RangeTblEntry-s generated for the child rels, and make use of the
1287 * AppendRelInfo entries for them to guide the real planning. (This is
1288 * rather inefficient; we could perhaps stop short of making a full Path
1289 * tree. But this whole function is inefficient and slated for
1290 * destruction, so let's not contort query_planner for that.)
1291 */
1292 {
1293 PlannerInfo *subroot;
1294
1295 /*
1296 * Flat-copy the PlannerInfo to prevent modification of the original.
1297 */
1298 subroot = makeNode(PlannerInfo);
1299 memcpy(subroot, root, sizeof(PlannerInfo));
1300
1301 /*
1302 * Make a deep copy of the parsetree for this planning cycle to mess
1303 * around with, and change it to look like a SELECT. (Hack alert: the
1304 * target RTE still has updatedCols set if this is an UPDATE, so that
1305 * expand_partitioned_rtentry will correctly update
1306 * subroot->partColsUpdated.)
1307 */
1308 subroot->parse = copyObject(root->parse);
1309
1310 subroot->parse->commandType = CMD_SELECT;
1311 subroot->parse->resultRelation = 0;
1312
1313 /*
1314 * Ensure the subroot has its own copy of the original
1315 * append_rel_list, since it'll be scribbled on. (Note that at this
1316 * point, the list only contains AppendRelInfos for flattened UNION
1317 * ALL subqueries.)
1318 */
1319 subroot->append_rel_list = copyObject(root->append_rel_list);
1320
1321 /*
1322 * Better make a private copy of the rowMarks, too.
1323 */
1324 subroot->rowMarks = copyObject(root->rowMarks);
1325
1326 /* There shouldn't be any OJ info to translate, as yet */
1327 Assert(subroot->join_info_list == NIL);
1328 /* and we haven't created PlaceHolderInfos, either */
1329 Assert(subroot->placeholder_list == NIL);
1330
1331 /* Generate Path(s) for accessing this result relation */
1332 grouping_planner(subroot, true, 0.0 /* retrieve all tuples */ );
1333
1334 /* Extract the info we need. */
1335 select_rtable = subroot->parse->rtable;
1336 select_appinfos = subroot->append_rel_list;
1337
1338 /*
1339 * We need to propagate partColsUpdated back, too. (The later
1340 * planning cycles will not set this because they won't run
1341 * expand_partitioned_rtentry for the UPDATE target.)
1342 */
1343 root->partColsUpdated = subroot->partColsUpdated;
1344 }
1345
1346 /*----------
1347 * Since only one rangetable can exist in the final plan, we need to make
1348 * sure that it contains all the RTEs needed for any child plan. This is
1349 * complicated by the need to use separate subquery RTEs for each child.
1350 * We arrange the final rtable as follows:
1351 * 1. All original rtable entries (with their original RT indexes).
1352 * 2. All the relation RTEs generated for children of the target table.
1353 * 3. Subquery RTEs for children after the first. We need N * (K - 1)
1354 * RT slots for this, if there are N subqueries and K child tables.
1355 * 4. Additional RTEs generated during the child planning runs, such as
1356 * children of inheritable RTEs other than the target table.
1357 * We assume that each child planning run will create an identical set
1358 * of type-4 RTEs.
1359 *
1360 * So the next thing to do is append the type-2 RTEs (the target table's
1361 * children) to the original rtable. We look through select_appinfos
1362 * to find them.
1363 *
1364 * To identify which AppendRelInfos are relevant as we thumb through
1365 * select_appinfos, we need to look for both direct and indirect children
1366 * of top_parentRTindex, so we use a bitmap of known parent relids.
1367 * expand_inherited_rtentry() always processes a parent before any of that
1368 * parent's children, so we should see an intermediate parent before its
1369 * children.
1370 *----------
1371 */
1372 child_appinfos = NIL;
1373 old_child_rtis = NIL;
1374 new_child_rtis = NIL;
1375 parent_relids = bms_make_singleton(top_parentRTindex);
1376 foreach(lc, select_appinfos)
1377 {
1378 AppendRelInfo *appinfo = lfirst_node(AppendRelInfo, lc);
1379 RangeTblEntry *child_rte;
1380
1381 /* append_rel_list contains all append rels; ignore others */
1382 if (!bms_is_member(appinfo->parent_relid, parent_relids))
1383 continue;
1384
1385 /* remember relevant AppendRelInfos for use below */
1386 child_appinfos = lappend(child_appinfos, appinfo);
1387
1388 /* extract RTE for this child rel */
1389 child_rte = rt_fetch(appinfo->child_relid, select_rtable);
1390
1391 /* and append it to the original rtable */
1392 parse->rtable = lappend(parse->rtable, child_rte);
1393
1394 /* remember child's index in the SELECT rtable */
1395 old_child_rtis = lappend_int(old_child_rtis, appinfo->child_relid);
1396
1397 /* and its new index in the final rtable */
1398 new_child_rtis = lappend_int(new_child_rtis, list_length(parse->rtable));
1399
1400 /* if child is itself partitioned, update parent_relids */
1401 if (child_rte->inh)
1402 {
1403 Assert(child_rte->relkind == RELKIND_PARTITIONED_TABLE);
1404 parent_relids = bms_add_member(parent_relids, appinfo->child_relid);
1405 }
1406 }
1407
1408 /*
1409 * It's possible that the RTIs we just assigned for the child rels in the
1410 * final rtable are different from what they were in the SELECT query.
1411 * Adjust the AppendRelInfos so that they will correctly map RT indexes to
1412 * the final indexes. We can do this left-to-right since no child rel's
1413 * final RT index could be greater than what it had in the SELECT query.
1414 */
1415 forboth(lc, old_child_rtis, lc2, new_child_rtis)
1416 {
1417 int old_child_rti = lfirst_int(lc);
1418 int new_child_rti = lfirst_int(lc2);
1419
1420 if (old_child_rti == new_child_rti)
1421 continue; /* nothing to do */
1422
1423 Assert(old_child_rti > new_child_rti);
1424
1425 ChangeVarNodes((Node *) child_appinfos,
1426 old_child_rti, new_child_rti, 0);
1427 }
1428
1429 /*
1430 * Now set up rangetable entries for subqueries for additional children
1431 * (the first child will just use the original ones). These all have to
1432 * look more or less real, or EXPLAIN will get unhappy; so we just make
1433 * them all clones of the original subqueries.
1434 */
1435 next_subquery_rti = list_length(parse->rtable) + 1;
1436 if (subqueryRTindexes != NULL)
1437 {
1438 int n_children = list_length(child_appinfos);
1439
1440 while (n_children-- > 1)
1441 {
1442 int oldrti = -1;
1443
1444 while ((oldrti = bms_next_member(subqueryRTindexes, oldrti)) >= 0)
1445 {
1446 RangeTblEntry *subqrte;
1447
1448 subqrte = rt_fetch(oldrti, parse->rtable);
1449 parse->rtable = lappend(parse->rtable, copyObject(subqrte));
1450 }
1451 }
1452 }
1453
1454 /*
1455 * The query for each child is obtained by translating the query for its
1456 * immediate parent, since the AppendRelInfo data we have shows deltas
1457 * between parents and children. We use the parent_parses array to
1458 * remember the appropriate query trees. This is indexed by parent relid.
1459 * Since the maximum number of parents is limited by the number of RTEs in
1460 * the SELECT query, we use that number to allocate the array. An extra
1461 * entry is needed since relids start from 1.
1462 */
1463 parent_parses = (Query **) palloc0((list_length(select_rtable) + 1) *
1464 sizeof(Query *));
1465 parent_parses[top_parentRTindex] = parse;
1466
1467 /*
1468 * And now we can get on with generating a plan for each child table.
1469 */
1470 foreach(lc, child_appinfos)
1471 {
1472 AppendRelInfo *appinfo = lfirst_node(AppendRelInfo, lc);
1473 Index this_subquery_rti = next_subquery_rti;
1474 Query *parent_parse;
1475 PlannerInfo *subroot;
1476 RangeTblEntry *child_rte;
1477 RelOptInfo *sub_final_rel;
1478 Path *subpath;
1479
1480 /*
1481 * expand_inherited_rtentry() always processes a parent before any of
1482 * that parent's children, so the parent query for this relation
1483 * should already be available.
1484 */
1485 parent_parse = parent_parses[appinfo->parent_relid];
1486 Assert(parent_parse != NULL);
1487
1488 /*
1489 * We need a working copy of the PlannerInfo so that we can control
1490 * propagation of information back to the main copy.
1491 */
1492 subroot = makeNode(PlannerInfo);
1493 memcpy(subroot, root, sizeof(PlannerInfo));
1494
1495 /*
1496 * Generate modified query with this rel as target. We first apply
1497 * adjust_appendrel_attrs, which copies the Query and changes
1498 * references to the parent RTE to refer to the current child RTE,
1499 * then fool around with subquery RTEs.
1500 */
1501 subroot->parse = (Query *)
1502 adjust_appendrel_attrs(subroot,
1503 (Node *) parent_parse,
1504 1, &appinfo);
1505
1506 /*
1507 * If there are securityQuals attached to the parent, move them to the
1508 * child rel (they've already been transformed properly for that).
1509 */
1510 parent_rte = rt_fetch(appinfo->parent_relid, subroot->parse->rtable);
1511 child_rte = rt_fetch(appinfo->child_relid, subroot->parse->rtable);
1512 child_rte->securityQuals = parent_rte->securityQuals;
1513 parent_rte->securityQuals = NIL;
1514
1515 /*
1516 * HACK: setting this to a value other than INHKIND_NONE signals to
1517 * relation_excluded_by_constraints() to treat the result relation as
1518 * being an appendrel member.
1519 */
1520 subroot->inhTargetKind =
1521 (rootRelation != 0) ? INHKIND_PARTITIONED : INHKIND_INHERITED;
1522
1523 /*
1524 * If this child is further partitioned, remember it as a parent.
1525 * Since a partitioned table does not have any data, we don't need to
1526 * create a plan for it, and we can stop processing it here. We do,
1527 * however, need to remember its modified PlannerInfo for use when
1528 * processing its children, since we'll update their varnos based on
1529 * the delta from immediate parent to child, not from top to child.
1530 *
1531 * Note: a very non-obvious point is that we have not yet added
1532 * duplicate subquery RTEs to the subroot's rtable. We mustn't,
1533 * because then its children would have two sets of duplicates,
1534 * confusing matters.
1535 */
1536 if (child_rte->inh)
1537 {
1538 Assert(child_rte->relkind == RELKIND_PARTITIONED_TABLE);
1539 parent_parses[appinfo->child_relid] = subroot->parse;
1540 continue;
1541 }
1542
1543 /*
1544 * Set the nominal target relation of the ModifyTable node if not
1545 * already done. If the target is a partitioned table, we already set
1546 * nominalRelation to refer to the partition root, above. For
1547 * non-partitioned inheritance cases, we'll use the first child
1548 * relation (even if it's excluded) as the nominal target relation.
1549 * Because of the way expand_inherited_rtentry works, that should be
1550 * the RTE representing the parent table in its role as a simple
1551 * member of the inheritance set.
1552 *
1553 * It would be logically cleaner to *always* use the inheritance
1554 * parent RTE as the nominal relation; but that RTE is not otherwise
1555 * referenced in the plan in the non-partitioned inheritance case.
1556 * Instead the duplicate child RTE created by expand_inherited_rtentry
1557 * is used elsewhere in the plan, so using the original parent RTE
1558 * would give rise to confusing use of multiple aliases in EXPLAIN
1559 * output for what the user will think is the "same" table. OTOH,
1560 * it's not a problem in the partitioned inheritance case, because
1561 * there is no duplicate RTE for the parent.
1562 */
1563 if (nominalRelation < 0)
1564 nominalRelation = appinfo->child_relid;
1565
1566 /*
1567 * As above, each child plan run needs its own append_rel_list and
1568 * rowmarks, which should start out as pristine copies of the
1569 * originals. There can't be any references to UPDATE/DELETE target
1570 * rels in them; but there could be subquery references, which we'll
1571 * fix up in a moment.
1572 */
1573 subroot->append_rel_list = copyObject(root->append_rel_list);
1574 subroot->rowMarks = copyObject(root->rowMarks);
1575
1576 /*
1577 * If this isn't the first child Query, adjust Vars and jointree
1578 * entries to reference the appropriate set of subquery RTEs.
1579 */
1580 if (final_rtable != NIL && subqueryRTindexes != NULL)
1581 {
1582 int oldrti = -1;
1583
1584 while ((oldrti = bms_next_member(subqueryRTindexes, oldrti)) >= 0)
1585 {
1586 Index newrti = next_subquery_rti++;
1587
1588 ChangeVarNodes((Node *) subroot->parse, oldrti, newrti, 0);
1589 ChangeVarNodes((Node *) subroot->append_rel_list,
1590 oldrti, newrti, 0);
1591 ChangeVarNodes((Node *) subroot->rowMarks, oldrti, newrti, 0);
1592 }
1593 }
1594
1595 /* There shouldn't be any OJ info to translate, as yet */
1596 Assert(subroot->join_info_list == NIL);
1597 /* and we haven't created PlaceHolderInfos, either */
1598 Assert(subroot->placeholder_list == NIL);
1599
1600 /* Generate Path(s) for accessing this result relation */
1601 grouping_planner(subroot, true, 0.0 /* retrieve all tuples */ );
1602
1603 /*
1604 * Select cheapest path in case there's more than one. We always run
1605 * modification queries to conclusion, so we care only for the
1606 * cheapest-total path.
1607 */
1608 sub_final_rel = fetch_upper_rel(subroot, UPPERREL_FINAL, NULL);
1609 set_cheapest(sub_final_rel);
1610 subpath = sub_final_rel->cheapest_total_path;
1611
1612 /*
1613 * If this child rel was excluded by constraint exclusion, exclude it
1614 * from the result plan.
1615 */
1616 if (IS_DUMMY_REL(sub_final_rel))
1617 continue;
1618
1619 /*
1620 * If this is the first non-excluded child, its post-planning rtable
1621 * becomes the initial contents of final_rtable; otherwise, copy its
1622 * modified subquery RTEs into final_rtable, to ensure we have sane
1623 * copies of those. Also save the first non-excluded child's version
1624 * of the rowmarks list; we assume all children will end up with
1625 * equivalent versions of that.
1626 */
1627 if (final_rtable == NIL)
1628 {
1629 final_rtable = subroot->parse->rtable;
1630 final_rowmarks = subroot->rowMarks;
1631 }
1632 else
1633 {
1634 Assert(list_length(final_rtable) ==
1635 list_length(subroot->parse->rtable));
1636 if (subqueryRTindexes != NULL)
1637 {
1638 int oldrti = -1;
1639
1640 while ((oldrti = bms_next_member(subqueryRTindexes, oldrti)) >= 0)
1641 {
1642 Index newrti = this_subquery_rti++;
1643 RangeTblEntry *subqrte;
1644 ListCell *newrticell;
1645
1646 subqrte = rt_fetch(newrti, subroot->parse->rtable);
1647 newrticell = list_nth_cell(final_rtable, newrti - 1);
1648 lfirst(newrticell) = subqrte;
1649 }
1650 }
1651 }
1652
1653 /*
1654 * We need to collect all the RelOptInfos from all child plans into
1655 * the main PlannerInfo, since setrefs.c will need them. We use the
1656 * last child's simple_rel_array, so we have to propagate forward the
1657 * RelOptInfos that were already built in previous children.
1658 */
1659 Assert(subroot->simple_rel_array_size >= save_rel_array_size);
1660 for (rti = 1; rti < save_rel_array_size; rti++)
1661 {
1662 RelOptInfo *brel = save_rel_array[rti];
1663
1664 if (brel)
1665 subroot->simple_rel_array[rti] = brel;
1666 }
1667 save_rel_array_size = subroot->simple_rel_array_size;
1668 save_rel_array = subroot->simple_rel_array;
1669 save_append_rel_array = subroot->append_rel_array;
1670
1671 /*
1672 * Make sure any initplans from this rel get into the outer list. Note
1673 * we're effectively assuming all children generate the same
1674 * init_plans.
1675 */
1676 root->init_plans = subroot->init_plans;
1677
1678 /* Build list of sub-paths */
1679 subpaths = lappend(subpaths, subpath);
1680
1681 /* Build list of modified subroots, too */
1682 subroots = lappend(subroots, subroot);
1683
1684 /* Build list of target-relation RT indexes */
1685 resultRelations = lappend_int(resultRelations, appinfo->child_relid);
1686
1687 /* Build lists of per-relation WCO and RETURNING targetlists */
1688 if (parse->withCheckOptions)
1689 withCheckOptionLists = lappend(withCheckOptionLists,
1690 subroot->parse->withCheckOptions);
1691 if (parse->returningList)
1692 returningLists = lappend(returningLists,
1693 subroot->parse->returningList);
1694
1695 Assert(!parse->onConflict);
1696 }
1697
1698 /* Result path must go into outer query's FINAL upperrel */
1699 final_rel = fetch_upper_rel(root, UPPERREL_FINAL, NULL);
1700
1701 /*
1702 * We don't currently worry about setting final_rel's consider_parallel
1703 * flag in this case, nor about allowing FDWs or create_upper_paths_hook
1704 * to get control here.
1705 */
1706
1707 if (subpaths == NIL)
1708 {
1709 /*
1710 * We managed to exclude every child rel, so generate a dummy path
1711 * representing the empty set. Although it's clear that no data will
1712 * be updated or deleted, we will still need to have a ModifyTable
1713 * node so that any statement triggers are executed. (This could be
1714 * cleaner if we fixed nodeModifyTable.c to support zero child nodes,
1715 * but that probably wouldn't be a net win.)
1716 */
1717 Path *dummy_path;
1718
1719 /* tlist processing never got done, either */
1720 root->processed_tlist = preprocess_targetlist(root);
1721 final_rel->reltarget = create_pathtarget(root, root->processed_tlist);
1722
1723 /* Make a dummy path, cf set_dummy_rel_pathlist() */
1724 dummy_path = (Path *) create_append_path(NULL, final_rel, NIL, NIL,
1725 NIL, NULL, 0, false,
1726 NIL, -1);
1727
1728 /* These lists must be nonempty to make a valid ModifyTable node */
1729 subpaths = list_make1(dummy_path);
1730 subroots = list_make1(root);
1731 resultRelations = list_make1_int(parse->resultRelation);
1732 if (parse->withCheckOptions)
1733 withCheckOptionLists = list_make1(parse->withCheckOptions);
1734 if (parse->returningList)
1735 returningLists = list_make1(parse->returningList);
1736 /* Disable tuple routing, too, just to be safe */
1737 root->partColsUpdated = false;
1738 }
1739 else
1740 {
1741 /*
1742 * Put back the final adjusted rtable into the master copy of the
1743 * Query. (We mustn't do this if we found no non-excluded children,
1744 * since we never saved an adjusted rtable at all.)
1745 */
1746 parse->rtable = final_rtable;
1747 root->simple_rel_array_size = save_rel_array_size;
1748 root->simple_rel_array = save_rel_array;
1749 root->append_rel_array = save_append_rel_array;
1750
1751 /* Must reconstruct master's simple_rte_array, too */
1752 root->simple_rte_array = (RangeTblEntry **)
1753 palloc0((list_length(final_rtable) + 1) * sizeof(RangeTblEntry *));
1754 rti = 1;
1755 foreach(lc, final_rtable)
1756 {
1757 RangeTblEntry *rte = lfirst_node(RangeTblEntry, lc);
1758
1759 root->simple_rte_array[rti++] = rte;
1760 }
1761
1762 /* Put back adjusted rowmarks, too */
1763 root->rowMarks = final_rowmarks;
1764 }
1765
1766 /*
1767 * If there was a FOR [KEY] UPDATE/SHARE clause, the LockRows node will
1768 * have dealt with fetching non-locked marked rows, else we need to have
1769 * ModifyTable do that.
1770 */
1771 if (parse->rowMarks)
1772 rowMarks = NIL;
1773 else
1774 rowMarks = root->rowMarks;
1775
1776 /* Create Path representing a ModifyTable to do the UPDATE/DELETE work */
1777 add_path(final_rel, (Path *)
1778 create_modifytable_path(root, final_rel,
1779 parse->commandType,
1780 parse->canSetTag,
1781 nominalRelation,
1782 rootRelation,
1783 root->partColsUpdated,
1784 resultRelations,
1785 subpaths,
1786 subroots,
1787 withCheckOptionLists,
1788 returningLists,
1789 rowMarks,
1790 NULL,
1791 assign_special_exec_param(root)));
1792}
1793
1794/*--------------------
1795 * grouping_planner
1796 * Perform planning steps related to grouping, aggregation, etc.
1797 *
1798 * This function adds all required top-level processing to the scan/join
1799 * Path(s) produced by query_planner.
1800 *
1801 * If inheritance_update is true, we're being called from inheritance_planner
1802 * and should not include a ModifyTable step in the resulting Path(s).
1803 * (inheritance_planner will create a single ModifyTable node covering all the
1804 * target tables.)
1805 *
1806 * tuple_fraction is the fraction of tuples we expect will be retrieved.
1807 * tuple_fraction is interpreted as follows:
1808 * 0: expect all tuples to be retrieved (normal case)
1809 * 0 < tuple_fraction < 1: expect the given fraction of tuples available
1810 * from the plan to be retrieved
1811 * tuple_fraction >= 1: tuple_fraction is the absolute number of tuples
1812 * expected to be retrieved (ie, a LIMIT specification)
1813 *
1814 * Returns nothing; the useful output is in the Paths we attach to the
1815 * (UPPERREL_FINAL, NULL) upperrel in *root. In addition,
1816 * root->processed_tlist contains the final processed targetlist.
1817 *
1818 * Note that we have not done set_cheapest() on the final rel; it's convenient
1819 * to leave this to the caller.
1820 *--------------------
1821 */
1822static void
1823grouping_planner(PlannerInfo *root, bool inheritance_update,
1824 double tuple_fraction)
1825{
1826 Query *parse = root->parse;
1827 int64 offset_est = 0;
1828 int64 count_est = 0;
1829 double limit_tuples = -1.0;
1830 bool have_postponed_srfs = false;
1831 PathTarget *final_target;
1832 List *final_targets;
1833 List *final_targets_contain_srfs;
1834 bool final_target_parallel_safe;
1835 RelOptInfo *current_rel;
1836 RelOptInfo *final_rel;
1837 FinalPathExtraData extra;
1838 ListCell *lc;
1839
1840 /* Tweak caller-supplied tuple_fraction if have LIMIT/OFFSET */
1841 if (parse->limitCount || parse->limitOffset)
1842 {
1843 tuple_fraction = preprocess_limit(root, tuple_fraction,
1844 &offset_est, &count_est);
1845
1846 /*
1847 * If we have a known LIMIT, and don't have an unknown OFFSET, we can
1848 * estimate the effects of using a bounded sort.
1849 */
1850 if (count_est > 0 && offset_est >= 0)
1851 limit_tuples = (double) count_est + (double) offset_est;
1852 }
1853
1854 /* Make tuple_fraction accessible to lower-level routines */
1855 root->tuple_fraction = tuple_fraction;
1856
1857 if (parse->setOperations)
1858 {
1859 /*
1860 * If there's a top-level ORDER BY, assume we have to fetch all the
1861 * tuples. This might be too simplistic given all the hackery below
1862 * to possibly avoid the sort; but the odds of accurate estimates here
1863 * are pretty low anyway. XXX try to get rid of this in favor of
1864 * letting plan_set_operations generate both fast-start and
1865 * cheapest-total paths.
1866 */
1867 if (parse->sortClause)
1868 root->tuple_fraction = 0.0;
1869
1870 /*
1871 * Construct Paths for set operations. The results will not need any
1872 * work except perhaps a top-level sort and/or LIMIT. Note that any
1873 * special work for recursive unions is the responsibility of
1874 * plan_set_operations.
1875 */
1876 current_rel = plan_set_operations(root);
1877
1878 /*
1879 * We should not need to call preprocess_targetlist, since we must be
1880 * in a SELECT query node. Instead, use the processed_tlist returned
1881 * by plan_set_operations (since this tells whether it returned any
1882 * resjunk columns!), and transfer any sort key information from the
1883 * original tlist.
1884 */
1885 Assert(parse->commandType == CMD_SELECT);
1886
1887 /* for safety, copy processed_tlist instead of modifying in-place */
1888 root->processed_tlist =
1889 postprocess_setop_tlist(copyObject(root->processed_tlist),
1890 parse->targetList);
1891
1892 /* Also extract the PathTarget form of the setop result tlist */
1893 final_target = current_rel->cheapest_total_path->pathtarget;
1894
1895 /* And check whether it's parallel safe */
1896 final_target_parallel_safe =
1897 is_parallel_safe(root, (Node *) final_target->exprs);
1898
1899 /* The setop result tlist couldn't contain any SRFs */
1900 Assert(!parse->hasTargetSRFs);
1901 final_targets = final_targets_contain_srfs = NIL;
1902
1903 /*
1904 * Can't handle FOR [KEY] UPDATE/SHARE here (parser should have
1905 * checked already, but let's make sure).
1906 */
1907 if (parse->rowMarks)
1908 ereport(ERROR,
1909 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
1910 /*------
1911 translator: %s is a SQL row locking clause such as FOR UPDATE */
1912 errmsg("%s is not allowed with UNION/INTERSECT/EXCEPT",
1913 LCS_asString(linitial_node(RowMarkClause,
1914 parse->rowMarks)->strength))));
1915
1916 /*
1917 * Calculate pathkeys that represent result ordering requirements
1918 */
1919 Assert(parse->distinctClause == NIL);
1920 root->sort_pathkeys = make_pathkeys_for_sortclauses(root,
1921 parse->sortClause,
1922 root->processed_tlist);
1923 }
1924 else
1925 {
1926 /* No set operations, do regular planning */
1927 PathTarget *sort_input_target;
1928 List *sort_input_targets;
1929 List *sort_input_targets_contain_srfs;
1930 bool sort_input_target_parallel_safe;
1931 PathTarget *grouping_target;
1932 List *grouping_targets;
1933 List *grouping_targets_contain_srfs;
1934 bool grouping_target_parallel_safe;
1935 PathTarget *scanjoin_target;
1936 List *scanjoin_targets;
1937 List *scanjoin_targets_contain_srfs;
1938 bool scanjoin_target_parallel_safe;
1939 bool scanjoin_target_same_exprs;
1940 bool have_grouping;
1941 AggClauseCosts agg_costs;
1942 WindowFuncLists *wflists = NULL;
1943 List *activeWindows = NIL;
1944 grouping_sets_data *gset_data = NULL;
1945 standard_qp_extra qp_extra;
1946
1947 /* A recursive query should always have setOperations */
1948 Assert(!root->hasRecursion);
1949
1950 /* Preprocess grouping sets and GROUP BY clause, if any */
1951 if (parse->groupingSets)
1952 {
1953 gset_data = preprocess_grouping_sets(root);
1954 }
1955 else
1956 {
1957 /* Preprocess regular GROUP BY clause, if any */
1958 if (parse->groupClause)
1959 parse->groupClause = preprocess_groupclause(root, NIL);
1960 }
1961
1962 /*
1963 * Preprocess targetlist. Note that much of the remaining planning
1964 * work will be done with the PathTarget representation of tlists, but
1965 * we must also maintain the full representation of the final tlist so
1966 * that we can transfer its decoration (resnames etc) to the topmost
1967 * tlist of the finished Plan. This is kept in processed_tlist.
1968 */
1969 root->processed_tlist = preprocess_targetlist(root);
1970
1971 /*
1972 * Collect statistics about aggregates for estimating costs, and mark
1973 * all the aggregates with resolved aggtranstypes. We must do this
1974 * before slicing and dicing the tlist into various pathtargets, else
1975 * some copies of the Aggref nodes might escape being marked with the
1976 * correct transtypes.
1977 *
1978 * Note: currently, we do not detect duplicate aggregates here. This
1979 * may result in somewhat-overestimated cost, which is fine for our
1980 * purposes since all Paths will get charged the same. But at some
1981 * point we might wish to do that detection in the planner, rather
1982 * than during executor startup.
1983 */
1984 MemSet(&agg_costs, 0, sizeof(AggClauseCosts));
1985 if (parse->hasAggs)
1986 {
1987 get_agg_clause_costs(root, (Node *) root->processed_tlist,
1988 AGGSPLIT_SIMPLE, &agg_costs);
1989 get_agg_clause_costs(root, parse->havingQual, AGGSPLIT_SIMPLE,
1990 &agg_costs);
1991 }
1992
1993 /*
1994 * Locate any window functions in the tlist. (We don't need to look
1995 * anywhere else, since expressions used in ORDER BY will be in there
1996 * too.) Note that they could all have been eliminated by constant
1997 * folding, in which case we don't need to do any more work.
1998 */
1999 if (parse->hasWindowFuncs)
2000 {
2001 wflists = find_window_functions((Node *) root->processed_tlist,
2002 list_length(parse->windowClause));
2003 if (wflists->numWindowFuncs > 0)
2004 activeWindows = select_active_windows(root, wflists);
2005 else
2006 parse->hasWindowFuncs = false;
2007 }
2008
2009 /*
2010 * Preprocess MIN/MAX aggregates, if any. Note: be careful about
2011 * adding logic between here and the query_planner() call. Anything
2012 * that is needed in MIN/MAX-optimizable cases will have to be
2013 * duplicated in planagg.c.
2014 */
2015 if (parse->hasAggs)
2016 preprocess_minmax_aggregates(root);
2017
2018 /*
2019 * Figure out whether there's a hard limit on the number of rows that
2020 * query_planner's result subplan needs to return. Even if we know a
2021 * hard limit overall, it doesn't apply if the query has any
2022 * grouping/aggregation operations, or SRFs in the tlist.
2023 */
2024 if (parse->groupClause ||
2025 parse->groupingSets ||
2026 parse->distinctClause ||
2027 parse->hasAggs ||
2028 parse->hasWindowFuncs ||
2029 parse->hasTargetSRFs ||
2030 root->hasHavingQual)
2031 root->limit_tuples = -1.0;
2032 else
2033 root->limit_tuples = limit_tuples;
2034
2035 /* Set up data needed by standard_qp_callback */
2036 qp_extra.activeWindows = activeWindows;
2037 qp_extra.groupClause = (gset_data
2038 ? (gset_data->rollups ? linitial_node(RollupData, gset_data->rollups)->groupClause : NIL)
2039 : parse->groupClause);
2040
2041 /*
2042 * Generate the best unsorted and presorted paths for the scan/join
2043 * portion of this Query, ie the processing represented by the
2044 * FROM/WHERE clauses. (Note there may not be any presorted paths.)
2045 * We also generate (in standard_qp_callback) pathkey representations
2046 * of the query's sort clause, distinct clause, etc.
2047 */
2048 current_rel = query_planner(root, standard_qp_callback, &qp_extra);
2049
2050 /*
2051 * Convert the query's result tlist into PathTarget format.
2052 *
2053 * Note: this cannot be done before query_planner() has performed
2054 * appendrel expansion, because that might add resjunk entries to
2055 * root->processed_tlist. Waiting till afterwards is also helpful
2056 * because the target width estimates can use per-Var width numbers
2057 * that were obtained within query_planner().
2058 */
2059 final_target = create_pathtarget(root, root->processed_tlist);
2060 final_target_parallel_safe =
2061 is_parallel_safe(root, (Node *) final_target->exprs);
2062
2063 /*
2064 * If ORDER BY was given, consider whether we should use a post-sort
2065 * projection, and compute the adjusted target for preceding steps if
2066 * so.
2067 */
2068 if (parse->sortClause)
2069 {
2070 sort_input_target = make_sort_input_target(root,
2071 final_target,
2072 &have_postponed_srfs);
2073 sort_input_target_parallel_safe =
2074 is_parallel_safe(root, (Node *) sort_input_target->exprs);
2075 }
2076 else
2077 {
2078 sort_input_target = final_target;
2079 sort_input_target_parallel_safe = final_target_parallel_safe;
2080 }
2081
2082 /*
2083 * If we have window functions to deal with, the output from any
2084 * grouping step needs to be what the window functions want;
2085 * otherwise, it should be sort_input_target.
2086 */
2087 if (activeWindows)
2088 {
2089 grouping_target = make_window_input_target(root,
2090 final_target,
2091 activeWindows);
2092 grouping_target_parallel_safe =
2093 is_parallel_safe(root, (Node *) grouping_target->exprs);
2094 }
2095 else
2096 {
2097 grouping_target = sort_input_target;
2098 grouping_target_parallel_safe = sort_input_target_parallel_safe;
2099 }
2100
2101 /*
2102 * If we have grouping or aggregation to do, the topmost scan/join
2103 * plan node must emit what the grouping step wants; otherwise, it
2104 * should emit grouping_target.
2105 */
2106 have_grouping = (parse->groupClause || parse->groupingSets ||
2107 parse->hasAggs || root->hasHavingQual);
2108 if (have_grouping)
2109 {
2110 scanjoin_target = make_group_input_target(root, final_target);
2111 scanjoin_target_parallel_safe =
2112 is_parallel_safe(root, (Node *) scanjoin_target->exprs);
2113 }
2114 else
2115 {
2116 scanjoin_target = grouping_target;
2117 scanjoin_target_parallel_safe = grouping_target_parallel_safe;
2118 }
2119
2120 /*
2121 * If there are any SRFs in the targetlist, we must separate each of
2122 * these PathTargets into SRF-computing and SRF-free targets. Replace
2123 * each of the named targets with a SRF-free version, and remember the
2124 * list of additional projection steps we need to add afterwards.
2125 */
2126 if (parse->hasTargetSRFs)
2127 {
2128 /* final_target doesn't recompute any SRFs in sort_input_target */
2129 split_pathtarget_at_srfs(root, final_target, sort_input_target,
2130 &final_targets,
2131 &final_targets_contain_srfs);
2132 final_target = linitial_node(PathTarget, final_targets);
2133 Assert(!linitial_int(final_targets_contain_srfs));
2134 /* likewise for sort_input_target vs. grouping_target */
2135 split_pathtarget_at_srfs(root, sort_input_target, grouping_target,
2136 &sort_input_targets,
2137 &sort_input_targets_contain_srfs);
2138 sort_input_target = linitial_node(PathTarget, sort_input_targets);
2139 Assert(!linitial_int(sort_input_targets_contain_srfs));
2140 /* likewise for grouping_target vs. scanjoin_target */
2141 split_pathtarget_at_srfs(root, grouping_target, scanjoin_target,
2142 &grouping_targets,
2143 &grouping_targets_contain_srfs);
2144 grouping_target = linitial_node(PathTarget, grouping_targets);
2145 Assert(!linitial_int(grouping_targets_contain_srfs));
2146 /* scanjoin_target will not have any SRFs precomputed for it */
2147 split_pathtarget_at_srfs(root, scanjoin_target, NULL,
2148 &scanjoin_targets,
2149 &scanjoin_targets_contain_srfs);
2150 scanjoin_target = linitial_node(PathTarget, scanjoin_targets);
2151 Assert(!linitial_int(scanjoin_targets_contain_srfs));
2152 }
2153 else
2154 {
2155 /* initialize lists; for most of these, dummy values are OK */
2156 final_targets = final_targets_contain_srfs = NIL;
2157 sort_input_targets = sort_input_targets_contain_srfs = NIL;
2158 grouping_targets = grouping_targets_contain_srfs = NIL;
2159 scanjoin_targets = list_make1(scanjoin_target);
2160 scanjoin_targets_contain_srfs = NIL;
2161 }
2162
2163 /* Apply scan/join target. */
2164 scanjoin_target_same_exprs = list_length(scanjoin_targets) == 1
2165 && equal(scanjoin_target->exprs, current_rel->reltarget->exprs);
2166 apply_scanjoin_target_to_paths(root, current_rel, scanjoin_targets,
2167 scanjoin_targets_contain_srfs,
2168 scanjoin_target_parallel_safe,
2169 scanjoin_target_same_exprs);
2170
2171 /*
2172 * Save the various upper-rel PathTargets we just computed into
2173 * root->upper_targets[]. The core code doesn't use this, but it
2174 * provides a convenient place for extensions to get at the info. For
2175 * consistency, we save all the intermediate targets, even though some
2176 * of the corresponding upperrels might not be needed for this query.
2177 */
2178 root->upper_targets[UPPERREL_FINAL] = final_target;
2179 root->upper_targets[UPPERREL_ORDERED] = final_target;
2180 root->upper_targets[UPPERREL_DISTINCT] = sort_input_target;
2181 root->upper_targets[UPPERREL_WINDOW] = sort_input_target;
2182 root->upper_targets[UPPERREL_GROUP_AGG] = grouping_target;
2183
2184 /*
2185 * If we have grouping and/or aggregation, consider ways to implement
2186 * that. We build a new upperrel representing the output of this
2187 * phase.
2188 */
2189 if (have_grouping)
2190 {
2191 current_rel = create_grouping_paths(root,
2192 current_rel,
2193 grouping_target,
2194 grouping_target_parallel_safe,
2195 &agg_costs,
2196 gset_data);
2197 /* Fix things up if grouping_target contains SRFs */
2198 if (parse->hasTargetSRFs)
2199 adjust_paths_for_srfs(root, current_rel,
2200 grouping_targets,
2201 grouping_targets_contain_srfs);
2202 }
2203
2204 /*
2205 * If we have window functions, consider ways to implement those. We
2206 * build a new upperrel representing the output of this phase.
2207 */
2208 if (activeWindows)
2209 {
2210 current_rel = create_window_paths(root,
2211 current_rel,
2212 grouping_target,
2213 sort_input_target,
2214 sort_input_target_parallel_safe,
2215 wflists,
2216 activeWindows);
2217 /* Fix things up if sort_input_target contains SRFs */
2218 if (parse->hasTargetSRFs)
2219 adjust_paths_for_srfs(root, current_rel,
2220 sort_input_targets,
2221 sort_input_targets_contain_srfs);
2222 }
2223
2224 /*
2225 * If there is a DISTINCT clause, consider ways to implement that. We
2226 * build a new upperrel representing the output of this phase.
2227 */
2228 if (parse->distinctClause)
2229 {
2230 current_rel = create_distinct_paths(root,
2231 current_rel);
2232 }
2233 } /* end of if (setOperations) */
2234
2235 /*
2236 * If ORDER BY was given, consider ways to implement that, and generate a
2237 * new upperrel containing only paths that emit the correct ordering and
2238 * project the correct final_target. We can apply the original
2239 * limit_tuples limit in sort costing here, but only if there are no
2240 * postponed SRFs.
2241 */
2242 if (parse->sortClause)
2243 {
2244 current_rel = create_ordered_paths(root,
2245 current_rel,
2246 final_target,
2247 final_target_parallel_safe,
2248 have_postponed_srfs ? -1.0 :
2249 limit_tuples);
2250 /* Fix things up if final_target contains SRFs */
2251 if (parse->hasTargetSRFs)
2252 adjust_paths_for_srfs(root, current_rel,
2253 final_targets,
2254 final_targets_contain_srfs);
2255 }
2256
2257 /*
2258 * Now we are prepared to build the final-output upperrel.
2259 */
2260 final_rel = fetch_upper_rel(root, UPPERREL_FINAL, NULL);
2261
2262 /*
2263 * If the input rel is marked consider_parallel and there's nothing that's
2264 * not parallel-safe in the LIMIT clause, then the final_rel can be marked
2265 * consider_parallel as well. Note that if the query has rowMarks or is
2266 * not a SELECT, consider_parallel will be false for every relation in the
2267 * query.
2268 */
2269 if (current_rel->consider_parallel &&
2270 is_parallel_safe(root, parse->limitOffset) &&
2271 is_parallel_safe(root, parse->limitCount))
2272 final_rel->consider_parallel = true;
2273
2274 /*
2275 * If the current_rel belongs to a single FDW, so does the final_rel.
2276 */
2277 final_rel->serverid = current_rel->serverid;
2278 final_rel->userid = current_rel->userid;
2279 final_rel->useridiscurrent = current_rel->useridiscurrent;
2280 final_rel->fdwroutine = current_rel->fdwroutine;
2281
2282 /*
2283 * Generate paths for the final_rel. Insert all surviving paths, with
2284 * LockRows, Limit, and/or ModifyTable steps added if needed.
2285 */
2286 foreach(lc, current_rel->pathlist)
2287 {
2288 Path *path = (Path *) lfirst(lc);
2289
2290 /*
2291 * If there is a FOR [KEY] UPDATE/SHARE clause, add the LockRows node.
2292 * (Note: we intentionally test parse->rowMarks not root->rowMarks
2293 * here. If there are only non-locking rowmarks, they should be
2294 * handled by the ModifyTable node instead. However, root->rowMarks
2295 * is what goes into the LockRows node.)
2296 */
2297 if (parse->rowMarks)
2298 {
2299 path = (Path *) create_lockrows_path(root, final_rel, path,
2300 root->rowMarks,
2301 assign_special_exec_param(root));
2302 }
2303
2304 /*
2305 * If there is a LIMIT/OFFSET clause, add the LIMIT node.
2306 */
2307 if (limit_needed(parse))
2308 {
2309 path = (Path *) create_limit_path(root, final_rel, path,
2310 parse->limitOffset,
2311 parse->limitCount,
2312 offset_est, count_est);
2313 }
2314
2315 /*
2316 * If this is an INSERT/UPDATE/DELETE, and we're not being called from
2317 * inheritance_planner, add the ModifyTable node.
2318 */
2319 if (parse->commandType != CMD_SELECT && !inheritance_update)
2320 {
2321 Index rootRelation;
2322 List *withCheckOptionLists;
2323 List *returningLists;
2324 List *rowMarks;
2325
2326 /*
2327 * If target is a partition root table, we need to mark the
2328 * ModifyTable node appropriately for that.
2329 */
2330 if (rt_fetch(parse->resultRelation, parse->rtable)->relkind ==
2331 RELKIND_PARTITIONED_TABLE)
2332 rootRelation = parse->resultRelation;
2333 else
2334 rootRelation = 0;
2335
2336 /*
2337 * Set up the WITH CHECK OPTION and RETURNING lists-of-lists, if
2338 * needed.
2339 */
2340 if (parse->withCheckOptions)
2341 withCheckOptionLists = list_make1(parse->withCheckOptions);
2342 else
2343 withCheckOptionLists = NIL;
2344
2345 if (parse->returningList)
2346 returningLists = list_make1(parse->returningList);
2347 else
2348 returningLists = NIL;
2349
2350 /*
2351 * If there was a FOR [KEY] UPDATE/SHARE clause, the LockRows node
2352 * will have dealt with fetching non-locked marked rows, else we
2353 * need to have ModifyTable do that.
2354 */
2355 if (parse->rowMarks)
2356 rowMarks = NIL;
2357 else
2358 rowMarks = root->rowMarks;
2359
2360 path = (Path *)
2361 create_modifytable_path(root, final_rel,
2362 parse->commandType,
2363 parse->canSetTag,
2364 parse->resultRelation,
2365 rootRelation,
2366 false,
2367 list_make1_int(parse->resultRelation),
2368 list_make1(path),
2369 list_make1(root),
2370 withCheckOptionLists,
2371 returningLists,
2372 rowMarks,
2373 parse->onConflict,
2374 assign_special_exec_param(root));
2375 }
2376
2377 /* And shove it into final_rel */
2378 add_path(final_rel, path);
2379 }
2380
2381 /*
2382 * Generate partial paths for final_rel, too, if outer query levels might
2383 * be able to make use of them.
2384 */
2385 if (final_rel->consider_parallel && root->query_level > 1 &&
2386 !limit_needed(parse))
2387 {
2388 Assert(!parse->rowMarks && parse->commandType == CMD_SELECT);
2389 foreach(lc, current_rel->partial_pathlist)
2390 {
2391 Path *partial_path = (Path *) lfirst(lc);
2392
2393 add_partial_path(final_rel, partial_path);
2394 }
2395 }
2396
2397 extra.limit_needed = limit_needed(parse);
2398 extra.limit_tuples = limit_tuples;
2399 extra.count_est = count_est;
2400 extra.offset_est = offset_est;
2401
2402 /*
2403 * If there is an FDW that's responsible for all baserels of the query,
2404 * let it consider adding ForeignPaths.
2405 */
2406 if (final_rel->fdwroutine &&
2407 final_rel->fdwroutine->GetForeignUpperPaths)
2408 final_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_FINAL,
2409 current_rel, final_rel,
2410 &extra);
2411
2412 /* Let extensions possibly add some more paths */
2413 if (create_upper_paths_hook)
2414 (*create_upper_paths_hook) (root, UPPERREL_FINAL,
2415 current_rel, final_rel, &extra);
2416
2417 /* Note: currently, we leave it to callers to do set_cheapest() */
2418}
2419
2420/*
2421 * Do preprocessing for groupingSets clause and related data. This handles the
2422 * preliminary steps of expanding the grouping sets, organizing them into lists
2423 * of rollups, and preparing annotations which will later be filled in with
2424 * size estimates.
2425 */
2426static grouping_sets_data *
2427preprocess_grouping_sets(PlannerInfo *root)
2428{
2429 Query *parse = root->parse;
2430 List *sets;
2431 int maxref = 0;
2432 ListCell *lc;
2433 ListCell *lc_set;
2434 grouping_sets_data *gd = palloc0(sizeof(grouping_sets_data));
2435
2436 parse->groupingSets = expand_grouping_sets(parse->groupingSets, -1);
2437
2438 gd->any_hashable = false;
2439 gd->unhashable_refs = NULL;
2440 gd->unsortable_refs = NULL;
2441 gd->unsortable_sets = NIL;
2442
2443 if (parse->groupClause)
2444 {
2445 ListCell *lc;
2446
2447 foreach(lc, parse->groupClause)
2448 {
2449 SortGroupClause *gc = lfirst_node(SortGroupClause, lc);
2450 Index ref = gc->tleSortGroupRef;
2451
2452 if (ref > maxref)
2453 maxref = ref;
2454
2455 if (!gc->hashable)
2456 gd->unhashable_refs = bms_add_member(gd->unhashable_refs, ref);
2457
2458 if (!OidIsValid(gc->sortop))
2459 gd->unsortable_refs = bms_add_member(gd->unsortable_refs, ref);
2460 }
2461 }
2462
2463 /* Allocate workspace array for remapping */
2464 gd->tleref_to_colnum_map = (int *) palloc((maxref + 1) * sizeof(int));
2465
2466 /*
2467 * If we have any unsortable sets, we must extract them before trying to
2468 * prepare rollups. Unsortable sets don't go through
2469 * reorder_grouping_sets, so we must apply the GroupingSetData annotation
2470 * here.
2471 */
2472 if (!bms_is_empty(gd->unsortable_refs))
2473 {
2474 List *sortable_sets = NIL;
2475
2476 foreach(lc, parse->groupingSets)
2477 {
2478 List *gset = (List *) lfirst(lc);
2479
2480 if (bms_overlap_list(gd->unsortable_refs, gset))
2481 {
2482 GroupingSetData *gs = makeNode(GroupingSetData);
2483
2484 gs->set = gset;
2485 gd->unsortable_sets = lappend(gd->unsortable_sets, gs);
2486
2487 /*
2488 * We must enforce here that an unsortable set is hashable;
2489 * later code assumes this. Parse analysis only checks that
2490 * every individual column is either hashable or sortable.
2491 *
2492 * Note that passing this test doesn't guarantee we can
2493 * generate a plan; there might be other showstoppers.
2494 */
2495 if (bms_overlap_list(gd->unhashable_refs, gset))
2496 ereport(ERROR,
2497 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
2498 errmsg("could not implement GROUP BY"),
2499 errdetail("Some of the datatypes only support hashing, while others only support sorting.")));
2500 }
2501 else
2502 sortable_sets = lappend(sortable_sets, gset);
2503 }
2504
2505 if (sortable_sets)
2506 sets = extract_rollup_sets(sortable_sets);
2507 else
2508 sets = NIL;
2509 }
2510 else
2511 sets = extract_rollup_sets(parse->groupingSets);
2512
2513 foreach(lc_set, sets)
2514 {
2515 List *current_sets = (List *) lfirst(lc_set);
2516 RollupData *rollup = makeNode(RollupData);
2517 GroupingSetData *gs;
2518
2519 /*
2520 * Reorder the current list of grouping sets into correct prefix
2521 * order. If only one aggregation pass is needed, try to make the
2522 * list match the ORDER BY clause; if more than one pass is needed, we
2523 * don't bother with that.
2524 *
2525 * Note that this reorders the sets from smallest-member-first to
2526 * largest-member-first, and applies the GroupingSetData annotations,
2527 * though the data will be filled in later.
2528 */
2529 current_sets = reorder_grouping_sets(current_sets,
2530 (list_length(sets) == 1
2531 ? parse->sortClause
2532 : NIL));
2533
2534 /*
2535 * Get the initial (and therefore largest) grouping set.
2536 */
2537 gs = linitial_node(GroupingSetData, current_sets);
2538
2539 /*
2540 * Order the groupClause appropriately. If the first grouping set is
2541 * empty, then the groupClause must also be empty; otherwise we have
2542 * to force the groupClause to match that grouping set's order.
2543 *
2544 * (The first grouping set can be empty even though parse->groupClause
2545 * is not empty only if all non-empty grouping sets are unsortable.
2546 * The groupClauses for hashed grouping sets are built later on.)
2547 */
2548 if (gs->set)
2549 rollup->groupClause = preprocess_groupclause(root, gs->set);
2550 else
2551 rollup->groupClause = NIL;
2552
2553 /*
2554 * Is it hashable? We pretend empty sets are hashable even though we
2555 * actually force them not to be hashed later. But don't bother if
2556 * there's nothing but empty sets (since in that case we can't hash
2557 * anything).
2558 */
2559 if (gs->set &&
2560 !bms_overlap_list(gd->unhashable_refs, gs->set))
2561 {
2562 rollup->hashable = true;
2563 gd->any_hashable = true;
2564 }
2565
2566 /*
2567 * Now that we've pinned down an order for the groupClause for this
2568 * list of grouping sets, we need to remap the entries in the grouping
2569 * sets from sortgrouprefs to plain indices (0-based) into the
2570 * groupClause for this collection of grouping sets. We keep the
2571 * original form for later use, though.
2572 */
2573 rollup->gsets = remap_to_groupclause_idx(rollup->groupClause,
2574 current_sets,
2575 gd->tleref_to_colnum_map);
2576 rollup->gsets_data = current_sets;
2577
2578 gd->rollups = lappend(gd->rollups, rollup);
2579 }
2580
2581 if (gd->unsortable_sets)
2582 {
2583 /*
2584 * We have not yet pinned down a groupclause for this, but we will
2585 * need index-based lists for estimation purposes. Construct
2586 * hash_sets_idx based on the entire original groupclause for now.
2587 */
2588 gd->hash_sets_idx = remap_to_groupclause_idx(parse->groupClause,
2589 gd->unsortable_sets,
2590 gd->tleref_to_colnum_map);
2591 gd->any_hashable = true;
2592 }
2593
2594 return gd;
2595}
2596
2597/*
2598 * Given a groupclause and a list of GroupingSetData, return equivalent sets
2599 * (without annotation) mapped to indexes into the given groupclause.
2600 */
2601static List *
2602remap_to_groupclause_idx(List *groupClause,
2603 List *gsets,
2604 int *tleref_to_colnum_map)
2605{
2606 int ref = 0;
2607 List *result = NIL;
2608 ListCell *lc;
2609
2610 foreach(lc, groupClause)
2611 {
2612 SortGroupClause *gc = lfirst_node(SortGroupClause, lc);
2613
2614 tleref_to_colnum_map[gc->tleSortGroupRef] = ref++;
2615 }
2616
2617 foreach(lc, gsets)
2618 {
2619 List *set = NIL;
2620 ListCell *lc2;
2621 GroupingSetData *gs = lfirst_node(GroupingSetData, lc);
2622
2623 foreach(lc2, gs->set)
2624 {
2625 set = lappend_int(set, tleref_to_colnum_map[lfirst_int(lc2)]);
2626 }
2627
2628 result = lappend(result, set);
2629 }
2630
2631 return result;
2632}
2633
2634
2635/*
2636 * preprocess_rowmarks - set up PlanRowMarks if needed
2637 */
2638static void
2639preprocess_rowmarks(PlannerInfo *root)
2640{
2641 Query *parse = root->parse;
2642 Bitmapset *rels;
2643 List *prowmarks;
2644 ListCell *l;
2645 int i;
2646
2647 if (parse->rowMarks)
2648 {
2649 /*
2650 * We've got trouble if FOR [KEY] UPDATE/SHARE appears inside
2651 * grouping, since grouping renders a reference to individual tuple
2652 * CTIDs invalid. This is also checked at parse time, but that's
2653 * insufficient because of rule substitution, query pullup, etc.
2654 */
2655 CheckSelectLocking(parse, linitial_node(RowMarkClause,
2656 parse->rowMarks)->strength);
2657 }
2658 else
2659 {
2660 /*
2661 * We only need rowmarks for UPDATE, DELETE, or FOR [KEY]
2662 * UPDATE/SHARE.
2663 */
2664 if (parse->commandType != CMD_UPDATE &&
2665 parse->commandType != CMD_DELETE)
2666 return;
2667 }
2668
2669 /*
2670 * We need to have rowmarks for all base relations except the target. We
2671 * make a bitmapset of all base rels and then remove the items we don't
2672 * need or have FOR [KEY] UPDATE/SHARE marks for.
2673 */
2674 rels = get_relids_in_jointree((Node *) parse->jointree, false);
2675 if (parse->resultRelation)
2676 rels = bms_del_member(rels, parse->resultRelation);
2677
2678 /*
2679 * Convert RowMarkClauses to PlanRowMark representation.
2680 */
2681 prowmarks = NIL;
2682 foreach(l, parse->rowMarks)
2683 {
2684 RowMarkClause *rc = lfirst_node(RowMarkClause, l);
2685 RangeTblEntry *rte = rt_fetch(rc->rti, parse->rtable);
2686 PlanRowMark *newrc;
2687
2688 /*
2689 * Currently, it is syntactically impossible to have FOR UPDATE et al
2690 * applied to an update/delete target rel. If that ever becomes
2691 * possible, we should drop the target from the PlanRowMark list.
2692 */
2693 Assert(rc->rti != parse->resultRelation);
2694
2695 /*
2696 * Ignore RowMarkClauses for subqueries; they aren't real tables and
2697 * can't support true locking. Subqueries that got flattened into the
2698 * main query should be ignored completely. Any that didn't will get
2699 * ROW_MARK_COPY items in the next loop.
2700 */
2701 if (rte->rtekind != RTE_RELATION)
2702 continue;
2703
2704 rels = bms_del_member(rels, rc->rti);
2705
2706 newrc = makeNode(PlanRowMark);
2707 newrc->rti = newrc->prti = rc->rti;
2708 newrc->rowmarkId = ++(root->glob->lastRowMarkId);
2709 newrc->markType = select_rowmark_type(rte, rc->strength);
2710 newrc->allMarkTypes = (1 << newrc->markType);
2711 newrc->strength = rc->strength;
2712 newrc->waitPolicy = rc->waitPolicy;
2713 newrc->isParent = false;
2714
2715 prowmarks = lappend(prowmarks, newrc);
2716 }
2717
2718 /*
2719 * Now, add rowmarks for any non-target, non-locked base relations.
2720 */
2721 i = 0;
2722 foreach(l, parse->rtable)
2723 {
2724 RangeTblEntry *rte = lfirst_node(RangeTblEntry, l);
2725 PlanRowMark *newrc;
2726
2727 i++;
2728 if (!bms_is_member(i, rels))
2729 continue;
2730
2731 newrc = makeNode(PlanRowMark);
2732 newrc->rti = newrc->prti = i;
2733 newrc->rowmarkId = ++(root->glob->lastRowMarkId);
2734 newrc->markType = select_rowmark_type(rte, LCS_NONE);
2735 newrc->allMarkTypes = (1 << newrc->markType);
2736 newrc->strength = LCS_NONE;
2737 newrc->waitPolicy = LockWaitBlock; /* doesn't matter */
2738 newrc->isParent = false;
2739
2740 prowmarks = lappend(prowmarks, newrc);
2741 }
2742
2743 root->rowMarks = prowmarks;
2744}
2745
2746/*
2747 * Select RowMarkType to use for a given table
2748 */
2749RowMarkType
2750select_rowmark_type(RangeTblEntry *rte, LockClauseStrength strength)
2751{
2752 if (rte->rtekind != RTE_RELATION)
2753 {
2754 /* If it's not a table at all, use ROW_MARK_COPY */
2755 return ROW_MARK_COPY;
2756 }
2757 else if (rte->relkind == RELKIND_FOREIGN_TABLE)
2758 {
2759 /* Let the FDW select the rowmark type, if it wants to */
2760 FdwRoutine *fdwroutine = GetFdwRoutineByRelId(rte->relid);
2761
2762 if (fdwroutine->GetForeignRowMarkType != NULL)
2763 return fdwroutine->GetForeignRowMarkType(rte, strength);
2764 /* Otherwise, use ROW_MARK_COPY by default */
2765 return ROW_MARK_COPY;
2766 }
2767 else
2768 {
2769 /* Regular table, apply the appropriate lock type */
2770 switch (strength)
2771 {
2772 case LCS_NONE:
2773
2774 /*
2775 * We don't need a tuple lock, only the ability to re-fetch
2776 * the row.
2777 */
2778 return ROW_MARK_REFERENCE;
2779 break;
2780 case LCS_FORKEYSHARE:
2781 return ROW_MARK_KEYSHARE;
2782 break;
2783 case LCS_FORSHARE:
2784 return ROW_MARK_SHARE;
2785 break;
2786 case LCS_FORNOKEYUPDATE:
2787 return ROW_MARK_NOKEYEXCLUSIVE;
2788 break;
2789 case LCS_FORUPDATE:
2790 return ROW_MARK_EXCLUSIVE;
2791 break;
2792 }
2793 elog(ERROR, "unrecognized LockClauseStrength %d", (int) strength);
2794 return ROW_MARK_EXCLUSIVE; /* keep compiler quiet */
2795 }
2796}
2797
2798/*
2799 * preprocess_limit - do pre-estimation for LIMIT and/or OFFSET clauses
2800 *
2801 * We try to estimate the values of the LIMIT/OFFSET clauses, and pass the
2802 * results back in *count_est and *offset_est. These variables are set to
2803 * 0 if the corresponding clause is not present, and -1 if it's present
2804 * but we couldn't estimate the value for it. (The "0" convention is OK
2805 * for OFFSET but a little bit bogus for LIMIT: effectively we estimate
2806 * LIMIT 0 as though it were LIMIT 1. But this is in line with the planner's
2807 * usual practice of never estimating less than one row.) These values will
2808 * be passed to create_limit_path, which see if you change this code.
2809 *
2810 * The return value is the suitably adjusted tuple_fraction to use for
2811 * planning the query. This adjustment is not overridable, since it reflects
2812 * plan actions that grouping_planner() will certainly take, not assumptions
2813 * about context.
2814 */
2815static double
2816preprocess_limit(PlannerInfo *root, double tuple_fraction,
2817 int64 *offset_est, int64 *count_est)
2818{
2819 Query *parse = root->parse;
2820 Node *est;
2821 double limit_fraction;
2822
2823 /* Should not be called unless LIMIT or OFFSET */
2824 Assert(parse->limitCount || parse->limitOffset);
2825
2826 /*
2827 * Try to obtain the clause values. We use estimate_expression_value
2828 * primarily because it can sometimes do something useful with Params.
2829 */
2830 if (parse->limitCount)
2831 {
2832 est = estimate_expression_value(root, parse->limitCount);
2833 if (est && IsA(est, Const))
2834 {
2835 if (((Const *) est)->constisnull)
2836 {
2837 /* NULL indicates LIMIT ALL, ie, no limit */
2838 *count_est = 0; /* treat as not present */
2839 }
2840 else
2841 {
2842 *count_est = DatumGetInt64(((Const *) est)->constvalue);
2843 if (*count_est <= 0)
2844 *count_est = 1; /* force to at least 1 */
2845 }
2846 }
2847 else
2848 *count_est = -1; /* can't estimate */
2849 }
2850 else
2851 *count_est = 0; /* not present */
2852
2853 if (parse->limitOffset)
2854 {
2855 est = estimate_expression_value(root, parse->limitOffset);
2856 if (est && IsA(est, Const))
2857 {
2858 if (((Const *) est)->constisnull)
2859 {
2860 /* Treat NULL as no offset; the executor will too */
2861 *offset_est = 0; /* treat as not present */
2862 }
2863 else
2864 {
2865 *offset_est = DatumGetInt64(((Const *) est)->constvalue);
2866 if (*offset_est < 0)
2867 *offset_est = 0; /* treat as not present */
2868 }
2869 }
2870 else
2871 *offset_est = -1; /* can't estimate */
2872 }
2873 else
2874 *offset_est = 0; /* not present */
2875
2876 if (*count_est != 0)
2877 {
2878 /*
2879 * A LIMIT clause limits the absolute number of tuples returned.
2880 * However, if it's not a constant LIMIT then we have to guess; for
2881 * lack of a better idea, assume 10% of the plan's result is wanted.
2882 */
2883 if (*count_est < 0 || *offset_est < 0)
2884 {
2885 /* LIMIT or OFFSET is an expression ... punt ... */
2886 limit_fraction = 0.10;
2887 }
2888 else
2889 {
2890 /* LIMIT (plus OFFSET, if any) is max number of tuples needed */
2891 limit_fraction = (double) *count_est + (double) *offset_est;
2892 }
2893
2894 /*
2895 * If we have absolute limits from both caller and LIMIT, use the
2896 * smaller value; likewise if they are both fractional. If one is
2897 * fractional and the other absolute, we can't easily determine which
2898 * is smaller, but we use the heuristic that the absolute will usually
2899 * be smaller.
2900 */
2901 if (tuple_fraction >= 1.0)
2902 {
2903 if (limit_fraction >= 1.0)
2904 {
2905 /* both absolute */
2906 tuple_fraction = Min(tuple_fraction, limit_fraction);
2907 }
2908 else
2909 {
2910 /* caller absolute, limit fractional; use caller's value */
2911 }
2912 }
2913 else if (tuple_fraction > 0.0)
2914 {
2915 if (limit_fraction >= 1.0)
2916 {
2917 /* caller fractional, limit absolute; use limit */
2918 tuple_fraction = limit_fraction;
2919 }
2920 else
2921 {
2922 /* both fractional */
2923 tuple_fraction = Min(tuple_fraction, limit_fraction);
2924 }
2925 }
2926 else
2927 {
2928 /* no info from caller, just use limit */
2929 tuple_fraction = limit_fraction;
2930 }
2931 }
2932 else if (*offset_est != 0 && tuple_fraction > 0.0)
2933 {
2934 /*
2935 * We have an OFFSET but no LIMIT. This acts entirely differently
2936 * from the LIMIT case: here, we need to increase rather than decrease
2937 * the caller's tuple_fraction, because the OFFSET acts to cause more
2938 * tuples to be fetched instead of fewer. This only matters if we got
2939 * a tuple_fraction > 0, however.
2940 *
2941 * As above, use 10% if OFFSET is present but unestimatable.
2942 */
2943 if (*offset_est < 0)
2944 limit_fraction = 0.10;
2945 else
2946 limit_fraction = (double) *offset_est;
2947
2948 /*
2949 * If we have absolute counts from both caller and OFFSET, add them
2950 * together; likewise if they are both fractional. If one is
2951 * fractional and the other absolute, we want to take the larger, and
2952 * we heuristically assume that's the fractional one.
2953 */
2954 if (tuple_fraction >= 1.0)
2955 {
2956 if (limit_fraction >= 1.0)
2957 {
2958 /* both absolute, so add them together */
2959 tuple_fraction += limit_fraction;
2960 }
2961 else
2962 {
2963 /* caller absolute, limit fractional; use limit */
2964 tuple_fraction = limit_fraction;
2965 }
2966 }
2967 else
2968 {
2969 if (limit_fraction >= 1.0)
2970 {
2971 /* caller fractional, limit absolute; use caller's value */
2972 }
2973 else
2974 {
2975 /* both fractional, so add them together */
2976 tuple_fraction += limit_fraction;
2977 if (tuple_fraction >= 1.0)
2978 tuple_fraction = 0.0; /* assume fetch all */
2979 }
2980 }
2981 }
2982
2983 return tuple_fraction;
2984}
2985
2986/*
2987 * limit_needed - do we actually need a Limit plan node?
2988 *
2989 * If we have constant-zero OFFSET and constant-null LIMIT, we can skip adding
2990 * a Limit node. This is worth checking for because "OFFSET 0" is a common
2991 * locution for an optimization fence. (Because other places in the planner
2992 * merely check whether parse->limitOffset isn't NULL, it will still work as
2993 * an optimization fence --- we're just suppressing unnecessary run-time
2994 * overhead.)
2995 *
2996 * This might look like it could be merged into preprocess_limit, but there's
2997 * a key distinction: here we need hard constants in OFFSET/LIMIT, whereas
2998 * in preprocess_limit it's good enough to consider estimated values.
2999 */
3000bool
3001limit_needed(Query *parse)
3002{
3003 Node *node;
3004
3005 node = parse->limitCount;
3006 if (node)
3007 {
3008 if (IsA(node, Const))
3009 {
3010 /* NULL indicates LIMIT ALL, ie, no limit */
3011 if (!((Const *) node)->constisnull)
3012 return true; /* LIMIT with a constant value */
3013 }
3014 else
3015 return true; /* non-constant LIMIT */
3016 }
3017
3018 node = parse->limitOffset;
3019 if (node)
3020 {
3021 if (IsA(node, Const))
3022 {
3023 /* Treat NULL as no offset; the executor would too */
3024 if (!((Const *) node)->constisnull)
3025 {
3026 int64 offset = DatumGetInt64(((Const *) node)->constvalue);
3027
3028 if (offset != 0)
3029 return true; /* OFFSET with a nonzero value */
3030 }
3031 }
3032 else
3033 return true; /* non-constant OFFSET */
3034 }
3035
3036 return false; /* don't need a Limit plan node */
3037}
3038
3039
3040/*
3041 * remove_useless_groupby_columns
3042 * Remove any columns in the GROUP BY clause that are redundant due to
3043 * being functionally dependent on other GROUP BY columns.
3044 *
3045 * Since some other DBMSes do not allow references to ungrouped columns, it's
3046 * not unusual to find all columns listed in GROUP BY even though listing the
3047 * primary-key columns would be sufficient. Deleting such excess columns
3048 * avoids redundant sorting work, so it's worth doing. When we do this, we
3049 * must mark the plan as dependent on the pkey constraint (compare the
3050 * parser's check_ungrouped_columns() and check_functional_grouping()).
3051 *
3052 * In principle, we could treat any NOT-NULL columns appearing in a UNIQUE
3053 * index as the determining columns. But as with check_functional_grouping(),
3054 * there's currently no way to represent dependency on a NOT NULL constraint,
3055 * so we consider only the pkey for now.
3056 */
3057static void
3058remove_useless_groupby_columns(PlannerInfo *root)
3059{
3060 Query *parse = root->parse;
3061 Bitmapset **groupbyattnos;
3062 Bitmapset **surplusvars;
3063 ListCell *lc;
3064 int relid;
3065
3066 /* No chance to do anything if there are less than two GROUP BY items */
3067 if (list_length(parse->groupClause) < 2)
3068 return;
3069
3070 /* Don't fiddle with the GROUP BY clause if the query has grouping sets */
3071 if (parse->groupingSets)
3072 return;
3073
3074 /*
3075 * Scan the GROUP BY clause to find GROUP BY items that are simple Vars.
3076 * Fill groupbyattnos[k] with a bitmapset of the column attnos of RTE k
3077 * that are GROUP BY items.
3078 */
3079 groupbyattnos = (Bitmapset **) palloc0(sizeof(Bitmapset *) *
3080 (list_length(parse->rtable) + 1));
3081 foreach(lc, parse->groupClause)
3082 {
3083 SortGroupClause *sgc = lfirst_node(SortGroupClause, lc);
3084 TargetEntry *tle = get_sortgroupclause_tle(sgc, parse->targetList);
3085 Var *var = (Var *) tle->expr;
3086
3087 /*
3088 * Ignore non-Vars and Vars from other query levels.
3089 *
3090 * XXX in principle, stable expressions containing Vars could also be
3091 * removed, if all the Vars are functionally dependent on other GROUP
3092 * BY items. But it's not clear that such cases occur often enough to
3093 * be worth troubling over.
3094 */
3095 if (!IsA(var, Var) ||
3096 var->varlevelsup > 0)
3097 continue;
3098
3099 /* OK, remember we have this Var */
3100 relid = var->varno;
3101 Assert(relid <= list_length(parse->rtable));
3102 groupbyattnos[relid] = bms_add_member(groupbyattnos[relid],
3103 var->varattno - FirstLowInvalidHeapAttributeNumber);
3104 }
3105
3106 /*
3107 * Consider each relation and see if it is possible to remove some of its
3108 * Vars from GROUP BY. For simplicity and speed, we do the actual removal
3109 * in a separate pass. Here, we just fill surplusvars[k] with a bitmapset
3110 * of the column attnos of RTE k that are removable GROUP BY items.
3111 */
3112 surplusvars = NULL; /* don't allocate array unless required */
3113 relid = 0;
3114 foreach(lc, parse->rtable)
3115 {
3116 RangeTblEntry *rte = lfirst_node(RangeTblEntry, lc);
3117 Bitmapset *relattnos;
3118 Bitmapset *pkattnos;
3119 Oid constraintOid;
3120
3121 relid++;
3122
3123 /* Only plain relations could have primary-key constraints */
3124 if (rte->rtekind != RTE_RELATION)
3125 continue;
3126
3127 /*
3128 * We must skip inheritance parent tables as some of the child rels
3129 * may cause duplicate rows. This cannot happen with partitioned
3130 * tables, however.
3131 */
3132 if (rte->inh && rte->relkind != RELKIND_PARTITIONED_TABLE)
3133 continue;
3134
3135 /* Nothing to do unless this rel has multiple Vars in GROUP BY */
3136 relattnos = groupbyattnos[relid];
3137 if (bms_membership(relattnos) != BMS_MULTIPLE)
3138 continue;
3139
3140 /*
3141 * Can't remove any columns for this rel if there is no suitable
3142 * (i.e., nondeferrable) primary key constraint.
3143 */
3144 pkattnos = get_primary_key_attnos(rte->relid, false, &constraintOid);
3145 if (pkattnos == NULL)
3146 continue;
3147
3148 /*
3149 * If the primary key is a proper subset of relattnos then we have
3150 * some items in the GROUP BY that can be removed.
3151 */
3152 if (bms_subset_compare(pkattnos, relattnos) == BMS_SUBSET1)
3153 {
3154 /*
3155 * To easily remember whether we've found anything to do, we don't
3156 * allocate the surplusvars[] array until we find something.
3157 */
3158 if (surplusvars == NULL)
3159 surplusvars = (Bitmapset **) palloc0(sizeof(Bitmapset *) *
3160 (list_length(parse->rtable) + 1));
3161
3162 /* Remember the attnos of the removable columns */
3163 surplusvars[relid] = bms_difference(relattnos, pkattnos);
3164
3165 /* Also, mark the resulting plan as dependent on this constraint */
3166 parse->constraintDeps = lappend_oid(parse->constraintDeps,
3167 constraintOid);
3168 }
3169 }
3170
3171 /*
3172 * If we found any surplus Vars, build a new GROUP BY clause without them.
3173 * (Note: this may leave some TLEs with unreferenced ressortgroupref
3174 * markings, but that's harmless.)
3175 */
3176 if (surplusvars != NULL)
3177 {
3178 List *new_groupby = NIL;
3179
3180 foreach(lc, parse->groupClause)
3181 {
3182 SortGroupClause *sgc = lfirst_node(SortGroupClause, lc);
3183 TargetEntry *tle = get_sortgroupclause_tle(sgc, parse->targetList);
3184 Var *var = (Var *) tle->expr;
3185
3186 /*
3187 * New list must include non-Vars, outer Vars, and anything not
3188 * marked as surplus.
3189 */
3190 if (!IsA(var, Var) ||
3191 var->varlevelsup > 0 ||
3192 !bms_is_member(var->varattno - FirstLowInvalidHeapAttributeNumber,
3193 surplusvars[var->varno]))
3194 new_groupby = lappend(new_groupby, sgc);
3195 }
3196
3197 parse->groupClause = new_groupby;
3198 }
3199}
3200
3201/*
3202 * preprocess_groupclause - do preparatory work on GROUP BY clause
3203 *
3204 * The idea here is to adjust the ordering of the GROUP BY elements
3205 * (which in itself is semantically insignificant) to match ORDER BY,
3206 * thereby allowing a single sort operation to both implement the ORDER BY
3207 * requirement and set up for a Unique step that implements GROUP BY.
3208 *
3209 * In principle it might be interesting to consider other orderings of the
3210 * GROUP BY elements, which could match the sort ordering of other
3211 * possible plans (eg an indexscan) and thereby reduce cost. We don't
3212 * bother with that, though. Hashed grouping will frequently win anyway.
3213 *
3214 * Note: we need no comparable processing of the distinctClause because
3215 * the parser already enforced that that matches ORDER BY.
3216 *
3217 * For grouping sets, the order of items is instead forced to agree with that
3218 * of the grouping set (and items not in the grouping set are skipped). The
3219 * work of sorting the order of grouping set elements to match the ORDER BY if
3220 * possible is done elsewhere.
3221 */
3222static List *
3223preprocess_groupclause(PlannerInfo *root, List *force)
3224{
3225 Query *parse = root->parse;
3226 List *new_groupclause = NIL;
3227 bool partial_match;
3228 ListCell *sl;
3229 ListCell *gl;
3230
3231 /* For grouping sets, we need to force the ordering */
3232 if (force)
3233 {
3234 foreach(sl, force)
3235 {
3236 Index ref = lfirst_int(sl);
3237 SortGroupClause *cl = get_sortgroupref_clause(ref, parse->groupClause);
3238
3239 new_groupclause = lappend(new_groupclause, cl);
3240 }
3241
3242 return new_groupclause;
3243 }
3244
3245 /* If no ORDER BY, nothing useful to do here */
3246 if (parse->sortClause == NIL)
3247 return parse->groupClause;
3248
3249 /*
3250 * Scan the ORDER BY clause and construct a list of matching GROUP BY
3251 * items, but only as far as we can make a matching prefix.
3252 *
3253 * This code assumes that the sortClause contains no duplicate items.
3254 */
3255 foreach(sl, parse->sortClause)
3256 {
3257 SortGroupClause *sc = lfirst_node(SortGroupClause, sl);
3258
3259 foreach(gl, parse->groupClause)
3260 {
3261 SortGroupClause *gc = lfirst_node(SortGroupClause, gl);
3262
3263 if (equal(gc, sc))
3264 {
3265 new_groupclause = lappend(new_groupclause, gc);
3266 break;
3267 }
3268 }
3269 if (gl == NULL)
3270 break; /* no match, so stop scanning */
3271 }
3272
3273 /* Did we match all of the ORDER BY list, or just some of it? */
3274 partial_match = (sl != NULL);
3275
3276 /* If no match at all, no point in reordering GROUP BY */
3277 if (new_groupclause == NIL)
3278 return parse->groupClause;
3279
3280 /*
3281 * Add any remaining GROUP BY items to the new list, but only if we were
3282 * able to make a complete match. In other words, we only rearrange the
3283 * GROUP BY list if the result is that one list is a prefix of the other
3284 * --- otherwise there's no possibility of a common sort. Also, give up
3285 * if there are any non-sortable GROUP BY items, since then there's no
3286 * hope anyway.
3287 */
3288 foreach(gl, parse->groupClause)
3289 {
3290 SortGroupClause *gc = lfirst_node(SortGroupClause, gl);
3291
3292 if (list_member_ptr(new_groupclause, gc))
3293 continue; /* it matched an ORDER BY item */
3294 if (partial_match)
3295 return parse->groupClause; /* give up, no common sort possible */
3296 if (!OidIsValid(gc->sortop))
3297 return parse->groupClause; /* give up, GROUP BY can't be sorted */
3298 new_groupclause = lappend(new_groupclause, gc);
3299 }
3300
3301 /* Success --- install the rearranged GROUP BY list */
3302 Assert(list_length(parse->groupClause) == list_length(new_groupclause));
3303 return new_groupclause;
3304}
3305
3306/*
3307 * Extract lists of grouping sets that can be implemented using a single
3308 * rollup-type aggregate pass each. Returns a list of lists of grouping sets.
3309 *
3310 * Input must be sorted with smallest sets first. Result has each sublist
3311 * sorted with smallest sets first.
3312 *
3313 * We want to produce the absolute minimum possible number of lists here to
3314 * avoid excess sorts. Fortunately, there is an algorithm for this; the problem
3315 * of finding the minimal partition of a partially-ordered set into chains
3316 * (which is what we need, taking the list of grouping sets as a poset ordered
3317 * by set inclusion) can be mapped to the problem of finding the maximum
3318 * cardinality matching on a bipartite graph, which is solvable in polynomial
3319 * time with a worst case of no worse than O(n^2.5) and usually much
3320 * better. Since our N is at most 4096, we don't need to consider fallbacks to
3321 * heuristic or approximate methods. (Planning time for a 12-d cube is under
3322 * half a second on my modest system even with optimization off and assertions
3323 * on.)
3324 */
3325static List *
3326extract_rollup_sets(List *groupingSets)
3327{
3328 int num_sets_raw = list_length(groupingSets);
3329 int num_empty = 0;
3330 int num_sets = 0; /* distinct sets */
3331 int num_chains = 0;
3332 List *result = NIL;
3333 List **results;
3334 List **orig_sets;
3335 Bitmapset **set_masks;
3336 int *chains;
3337 short **adjacency;
3338 short *adjacency_buf;
3339 BipartiteMatchState *state;
3340 int i;
3341 int j;
3342 int j_size;
3343 ListCell *lc1 = list_head(groupingSets);
3344 ListCell *lc;
3345
3346 /*
3347 * Start by stripping out empty sets. The algorithm doesn't require this,
3348 * but the planner currently needs all empty sets to be returned in the
3349 * first list, so we strip them here and add them back after.
3350 */
3351 while (lc1 && lfirst(lc1) == NIL)
3352 {
3353 ++num_empty;
3354 lc1 = lnext(lc1);
3355 }
3356
3357 /* bail out now if it turns out that all we had were empty sets. */
3358 if (!lc1)
3359 return list_make1(groupingSets);
3360
3361 /*----------
3362 * We don't strictly need to remove duplicate sets here, but if we don't,
3363 * they tend to become scattered through the result, which is a bit
3364 * confusing (and irritating if we ever decide to optimize them out).
3365 * So we remove them here and add them back after.
3366 *
3367 * For each non-duplicate set, we fill in the following:
3368 *
3369 * orig_sets[i] = list of the original set lists
3370 * set_masks[i] = bitmapset for testing inclusion
3371 * adjacency[i] = array [n, v1, v2, ... vn] of adjacency indices
3372 *
3373 * chains[i] will be the result group this set is assigned to.
3374 *
3375 * We index all of these from 1 rather than 0 because it is convenient
3376 * to leave 0 free for the NIL node in the graph algorithm.
3377 *----------
3378 */
3379 orig_sets = palloc0((num_sets_raw + 1) * sizeof(List *));
3380 set_masks = palloc0((num_sets_raw + 1) * sizeof(Bitmapset *));
3381 adjacency = palloc0((num_sets_raw + 1) * sizeof(short *));
3382 adjacency_buf = palloc((num_sets_raw + 1) * sizeof(short));
3383
3384 j_size = 0;
3385 j = 0;
3386 i = 1;
3387
3388 for_each_cell(lc, lc1)
3389 {
3390 List *candidate = (List *) lfirst(lc);
3391 Bitmapset *candidate_set = NULL;
3392 ListCell *lc2;
3393 int dup_of = 0;
3394
3395 foreach(lc2, candidate)
3396 {
3397 candidate_set = bms_add_member(candidate_set, lfirst_int(lc2));
3398 }
3399
3400 /* we can only be a dup if we're the same length as a previous set */
3401 if (j_size == list_length(candidate))
3402 {
3403 int k;
3404
3405 for (k = j; k < i; ++k)
3406 {
3407 if (bms_equal(set_masks[k], candidate_set))
3408 {
3409 dup_of = k;
3410 break;
3411 }
3412 }
3413 }
3414 else if (j_size < list_length(candidate))
3415 {
3416 j_size = list_length(candidate);
3417 j = i;
3418 }
3419
3420 if (dup_of > 0)
3421 {
3422 orig_sets[dup_of] = lappend(orig_sets[dup_of], candidate);
3423 bms_free(candidate_set);
3424 }
3425 else
3426 {
3427 int k;
3428 int n_adj = 0;
3429
3430 orig_sets[i] = list_make1(candidate);
3431 set_masks[i] = candidate_set;
3432
3433 /* fill in adjacency list; no need to compare equal-size sets */
3434
3435 for (k = j - 1; k > 0; --k)
3436 {
3437 if (bms_is_subset(set_masks[k], candidate_set))
3438 adjacency_buf[++n_adj] = k;
3439 }
3440
3441 if (n_adj > 0)
3442 {
3443 adjacency_buf[0] = n_adj;
3444 adjacency[i] = palloc((n_adj + 1) * sizeof(short));
3445 memcpy(adjacency[i], adjacency_buf, (n_adj + 1) * sizeof(short));
3446 }
3447 else
3448 adjacency[i] = NULL;
3449
3450 ++i;
3451 }
3452 }
3453
3454 num_sets = i - 1;
3455
3456 /*
3457 * Apply the graph matching algorithm to do the work.
3458 */
3459 state = BipartiteMatch(num_sets, num_sets, adjacency);
3460
3461 /*
3462 * Now, the state->pair* fields have the info we need to assign sets to
3463 * chains. Two sets (u,v) belong to the same chain if pair_uv[u] = v or
3464 * pair_vu[v] = u (both will be true, but we check both so that we can do
3465 * it in one pass)
3466 */
3467 chains = palloc0((num_sets + 1) * sizeof(int));
3468
3469 for (i = 1; i <= num_sets; ++i)
3470 {
3471 int u = state->pair_vu[i];
3472 int v = state->pair_uv[i];
3473
3474 if (u > 0 && u < i)
3475 chains[i] = chains[u];
3476 else if (v > 0 && v < i)
3477 chains[i] = chains[v];
3478 else
3479 chains[i] = ++num_chains;
3480 }
3481
3482 /* build result lists. */
3483 results = palloc0((num_chains + 1) * sizeof(List *));
3484
3485 for (i = 1; i <= num_sets; ++i)
3486 {
3487 int c = chains[i];
3488
3489 Assert(c > 0);
3490
3491 results[c] = list_concat(results[c], orig_sets[i]);
3492 }
3493
3494 /* push any empty sets back on the first list. */
3495 while (num_empty-- > 0)
3496 results[1] = lcons(NIL, results[1]);
3497
3498 /* make result list */
3499 for (i = 1; i <= num_chains; ++i)
3500 result = lappend(result, results[i]);
3501
3502 /*
3503 * Free all the things.
3504 *
3505 * (This is over-fussy for small sets but for large sets we could have
3506 * tied up a nontrivial amount of memory.)
3507 */
3508 BipartiteMatchFree(state);
3509 pfree(results);
3510 pfree(chains);
3511 for (i = 1; i <= num_sets; ++i)
3512 if (adjacency[i])
3513 pfree(adjacency[i]);
3514 pfree(adjacency);
3515 pfree(adjacency_buf);
3516 pfree(orig_sets);
3517 for (i = 1; i <= num_sets; ++i)
3518 bms_free(set_masks[i]);
3519 pfree(set_masks);
3520
3521 return result;
3522}
3523
3524/*
3525 * Reorder the elements of a list of grouping sets such that they have correct
3526 * prefix relationships. Also inserts the GroupingSetData annotations.
3527 *
3528 * The input must be ordered with smallest sets first; the result is returned
3529 * with largest sets first. Note that the result shares no list substructure
3530 * with the input, so it's safe for the caller to modify it later.
3531 *
3532 * If we're passed in a sortclause, we follow its order of columns to the
3533 * extent possible, to minimize the chance that we add unnecessary sorts.
3534 * (We're trying here to ensure that GROUPING SETS ((a,b,c),(c)) ORDER BY c,b,a
3535 * gets implemented in one pass.)
3536 */
3537static List *
3538reorder_grouping_sets(List *groupingsets, List *sortclause)
3539{
3540 ListCell *lc;
3541 List *previous = NIL;
3542 List *result = NIL;
3543
3544 foreach(lc, groupingsets)
3545 {
3546 List *candidate = (List *) lfirst(lc);
3547 List *new_elems = list_difference_int(candidate, previous);
3548 GroupingSetData *gs = makeNode(GroupingSetData);
3549
3550 while (list_length(sortclause) > list_length(previous) &&
3551 list_length(new_elems) > 0)
3552 {
3553 SortGroupClause *sc = list_nth(sortclause, list_length(previous));
3554 int ref = sc->tleSortGroupRef;
3555
3556 if (list_member_int(new_elems, ref))
3557 {
3558 previous = lappend_int(previous, ref);
3559 new_elems = list_delete_int(new_elems, ref);
3560 }
3561 else
3562 {
3563 /* diverged from the sortclause; give up on it */
3564 sortclause = NIL;
3565 break;
3566 }
3567 }
3568
3569 /*
3570 * Safe to use list_concat (which shares cells of the second arg)
3571 * because we know that new_elems does not share cells with anything.
3572 */
3573 previous = list_concat(previous, new_elems);
3574
3575 gs->set = list_copy(previous);
3576 result = lcons(gs, result);
3577 }
3578
3579 list_free(previous);
3580
3581 return result;
3582}
3583
3584/*
3585 * Compute query_pathkeys and other pathkeys during plan generation
3586 */
3587static void
3588standard_qp_callback(PlannerInfo *root, void *extra)
3589{
3590 Query *parse = root->parse;
3591 standard_qp_extra *qp_extra = (standard_qp_extra *) extra;
3592 List *tlist = root->processed_tlist;
3593 List *activeWindows = qp_extra->activeWindows;
3594
3595 /*
3596 * Calculate pathkeys that represent grouping/ordering requirements. The
3597 * sortClause is certainly sort-able, but GROUP BY and DISTINCT might not
3598 * be, in which case we just leave their pathkeys empty.
3599 */
3600 if (qp_extra->groupClause &&
3601 grouping_is_sortable(qp_extra->groupClause))
3602 root->group_pathkeys =
3603 make_pathkeys_for_sortclauses(root,
3604 qp_extra->groupClause,
3605 tlist);
3606 else
3607 root->group_pathkeys = NIL;
3608
3609 /* We consider only the first (bottom) window in pathkeys logic */
3610 if (activeWindows != NIL)
3611 {
3612 WindowClause *wc = linitial_node(WindowClause, activeWindows);
3613
3614 root->window_pathkeys = make_pathkeys_for_window(root,
3615 wc,
3616 tlist);
3617 }
3618 else
3619 root->window_pathkeys = NIL;
3620
3621 if (parse->distinctClause &&
3622 grouping_is_sortable(parse->distinctClause))
3623 root->distinct_pathkeys =
3624 make_pathkeys_for_sortclauses(root,
3625 parse->distinctClause,
3626 tlist);
3627 else
3628 root->distinct_pathkeys = NIL;
3629
3630 root->sort_pathkeys =
3631 make_pathkeys_for_sortclauses(root,
3632 parse->sortClause,
3633 tlist);
3634
3635 /*
3636 * Figure out whether we want a sorted result from query_planner.
3637 *
3638 * If we have a sortable GROUP BY clause, then we want a result sorted
3639 * properly for grouping. Otherwise, if we have window functions to
3640 * evaluate, we try to sort for the first window. Otherwise, if there's a
3641 * sortable DISTINCT clause that's more rigorous than the ORDER BY clause,
3642 * we try to produce output that's sufficiently well sorted for the
3643 * DISTINCT. Otherwise, if there is an ORDER BY clause, we want to sort
3644 * by the ORDER BY clause.
3645 *
3646 * Note: if we have both ORDER BY and GROUP BY, and ORDER BY is a superset
3647 * of GROUP BY, it would be tempting to request sort by ORDER BY --- but
3648 * that might just leave us failing to exploit an available sort order at
3649 * all. Needs more thought. The choice for DISTINCT versus ORDER BY is
3650 * much easier, since we know that the parser ensured that one is a
3651 * superset of the other.
3652 */
3653 if (root->group_pathkeys)
3654 root->query_pathkeys = root->group_pathkeys;
3655 else if (root->window_pathkeys)
3656 root->query_pathkeys = root->window_pathkeys;
3657 else if (list_length(root->distinct_pathkeys) >
3658 list_length(root->sort_pathkeys))
3659 root->query_pathkeys = root->distinct_pathkeys;
3660 else if (root->sort_pathkeys)
3661 root->query_pathkeys = root->sort_pathkeys;
3662 else
3663 root->query_pathkeys = NIL;
3664}
3665
3666/*
3667 * Estimate number of groups produced by grouping clauses (1 if not grouping)
3668 *
3669 * path_rows: number of output rows from scan/join step
3670 * gd: grouping sets data including list of grouping sets and their clauses
3671 * target_list: target list containing group clause references
3672 *
3673 * If doing grouping sets, we also annotate the gsets data with the estimates
3674 * for each set and each individual rollup list, with a view to later
3675 * determining whether some combination of them could be hashed instead.
3676 */
3677static double
3678get_number_of_groups(PlannerInfo *root,
3679 double path_rows,
3680 grouping_sets_data *gd,
3681 List *target_list)
3682{
3683 Query *parse = root->parse;
3684 double dNumGroups;
3685
3686 if (parse->groupClause)
3687 {
3688 List *groupExprs;
3689
3690 if (parse->groupingSets)
3691 {
3692 /* Add up the estimates for each grouping set */
3693 ListCell *lc;
3694 ListCell *lc2;
3695
3696 Assert(gd); /* keep Coverity happy */
3697
3698 dNumGroups = 0;
3699
3700 foreach(lc, gd->rollups)
3701 {
3702 RollupData *rollup = lfirst_node(RollupData, lc);
3703 ListCell *lc;
3704
3705 groupExprs = get_sortgrouplist_exprs(rollup->groupClause,
3706 target_list);
3707
3708 rollup->numGroups = 0.0;
3709
3710 forboth(lc, rollup->gsets, lc2, rollup->gsets_data)
3711 {
3712 List *gset = (List *) lfirst(lc);
3713 GroupingSetData *gs = lfirst_node(GroupingSetData, lc2);
3714 double numGroups = estimate_num_groups(root,
3715 groupExprs,
3716 path_rows,
3717 &gset);
3718
3719 gs->numGroups = numGroups;
3720 rollup->numGroups += numGroups;
3721 }
3722
3723 dNumGroups += rollup->numGroups;
3724 }
3725
3726 if (gd->hash_sets_idx)
3727 {
3728 ListCell *lc;
3729
3730 gd->dNumHashGroups = 0;
3731
3732 groupExprs = get_sortgrouplist_exprs(parse->groupClause,
3733 target_list);
3734
3735 forboth(lc, gd->hash_sets_idx, lc2, gd->unsortable_sets)
3736 {
3737 List *gset = (List *) lfirst(lc);
3738 GroupingSetData *gs = lfirst_node(GroupingSetData, lc2);
3739 double numGroups = estimate_num_groups(root,
3740 groupExprs,
3741 path_rows,
3742 &gset);
3743
3744 gs->numGroups = numGroups;
3745 gd->dNumHashGroups += numGroups;
3746 }
3747
3748 dNumGroups += gd->dNumHashGroups;
3749 }
3750 }
3751 else
3752 {
3753 /* Plain GROUP BY */
3754 groupExprs = get_sortgrouplist_exprs(parse->groupClause,
3755 target_list);
3756
3757 dNumGroups = estimate_num_groups(root, groupExprs, path_rows,
3758 NULL);
3759 }
3760 }
3761 else if (parse->groupingSets)
3762 {
3763 /* Empty grouping sets ... one result row for each one */
3764 dNumGroups = list_length(parse->groupingSets);
3765 }
3766 else if (parse->hasAggs || root->hasHavingQual)
3767 {
3768 /* Plain aggregation, one result row */
3769 dNumGroups = 1;
3770 }
3771 else
3772 {
3773 /* Not grouping */
3774 dNumGroups = 1;
3775 }
3776
3777 return dNumGroups;
3778}
3779
3780/*
3781 * create_grouping_paths
3782 *
3783 * Build a new upperrel containing Paths for grouping and/or aggregation.
3784 * Along the way, we also build an upperrel for Paths which are partially
3785 * grouped and/or aggregated. A partially grouped and/or aggregated path
3786 * needs a FinalizeAggregate node to complete the aggregation. Currently,
3787 * the only partially grouped paths we build are also partial paths; that
3788 * is, they need a Gather and then a FinalizeAggregate.
3789 *
3790 * input_rel: contains the source-data Paths
3791 * target: the pathtarget for the result Paths to compute
3792 * agg_costs: cost info about all aggregates in query (in AGGSPLIT_SIMPLE mode)
3793 * gd: grouping sets data including list of grouping sets and their clauses
3794 *
3795 * Note: all Paths in input_rel are expected to return the target computed
3796 * by make_group_input_target.
3797 */
3798static RelOptInfo *
3799create_grouping_paths(PlannerInfo *root,
3800 RelOptInfo *input_rel,
3801 PathTarget *target,
3802 bool target_parallel_safe,
3803 const AggClauseCosts *agg_costs,
3804 grouping_sets_data *gd)
3805{
3806 Query *parse = root->parse;
3807 RelOptInfo *grouped_rel;
3808 RelOptInfo *partially_grouped_rel;
3809
3810 /*
3811 * Create grouping relation to hold fully aggregated grouping and/or
3812 * aggregation paths.
3813 */
3814 grouped_rel = make_grouping_rel(root, input_rel, target,
3815 target_parallel_safe, parse->havingQual);
3816
3817 /*
3818 * Create either paths for a degenerate grouping or paths for ordinary
3819 * grouping, as appropriate.
3820 */
3821 if (is_degenerate_grouping(root))
3822 create_degenerate_grouping_paths(root, input_rel, grouped_rel);
3823 else
3824 {
3825 int flags = 0;
3826 GroupPathExtraData extra;
3827
3828 /*
3829 * Determine whether it's possible to perform sort-based
3830 * implementations of grouping. (Note that if groupClause is empty,
3831 * grouping_is_sortable() is trivially true, and all the
3832 * pathkeys_contained_in() tests will succeed too, so that we'll
3833 * consider every surviving input path.)
3834 *
3835 * If we have grouping sets, we might be able to sort some but not all
3836 * of them; in this case, we need can_sort to be true as long as we
3837 * must consider any sorted-input plan.
3838 */
3839 if ((gd && gd->rollups != NIL)
3840 || grouping_is_sortable(parse->groupClause))
3841 flags |= GROUPING_CAN_USE_SORT;
3842
3843 /*
3844 * Determine whether we should consider hash-based implementations of
3845 * grouping.
3846 *
3847 * Hashed aggregation only applies if we're grouping. If we have
3848 * grouping sets, some groups might be hashable but others not; in
3849 * this case we set can_hash true as long as there is nothing globally
3850 * preventing us from hashing (and we should therefore consider plans
3851 * with hashes).
3852 *
3853 * Executor doesn't support hashed aggregation with DISTINCT or ORDER
3854 * BY aggregates. (Doing so would imply storing *all* the input
3855 * values in the hash table, and/or running many sorts in parallel,
3856 * either of which seems like a certain loser.) We similarly don't
3857 * support ordered-set aggregates in hashed aggregation, but that case
3858 * is also included in the numOrderedAggs count.
3859 *
3860 * Note: grouping_is_hashable() is much more expensive to check than
3861 * the other gating conditions, so we want to do it last.
3862 */
3863 if ((parse->groupClause != NIL &&
3864 agg_costs->numOrderedAggs == 0 &&
3865 (gd ? gd->any_hashable : grouping_is_hashable(parse->groupClause))))
3866 flags |= GROUPING_CAN_USE_HASH;
3867
3868 /*
3869 * Determine whether partial aggregation is possible.
3870 */
3871 if (can_partial_agg(root, agg_costs))
3872 flags |= GROUPING_CAN_PARTIAL_AGG;
3873
3874 extra.flags = flags;
3875 extra.target_parallel_safe = target_parallel_safe;
3876 extra.havingQual = parse->havingQual;
3877 extra.targetList = parse->targetList;
3878 extra.partial_costs_set = false;
3879
3880 /*
3881 * Determine whether partitionwise aggregation is in theory possible.
3882 * It can be disabled by the user, and for now, we don't try to
3883 * support grouping sets. create_ordinary_grouping_paths() will check
3884 * additional conditions, such as whether input_rel is partitioned.
3885 */
3886 if (enable_partitionwise_aggregate && !parse->groupingSets)
3887 extra.patype = PARTITIONWISE_AGGREGATE_FULL;
3888 else
3889 extra.patype = PARTITIONWISE_AGGREGATE_NONE;
3890
3891 create_ordinary_grouping_paths(root, input_rel, grouped_rel,
3892 agg_costs, gd, &extra,
3893 &partially_grouped_rel);
3894 }
3895
3896 set_cheapest(grouped_rel);
3897 return grouped_rel;
3898}
3899
3900/*
3901 * make_grouping_rel
3902 *
3903 * Create a new grouping rel and set basic properties.
3904 *
3905 * input_rel represents the underlying scan/join relation.
3906 * target is the output expected from the grouping relation.
3907 */
3908static RelOptInfo *
3909make_grouping_rel(PlannerInfo *root, RelOptInfo *input_rel,
3910 PathTarget *target, bool target_parallel_safe,
3911 Node *havingQual)
3912{
3913 RelOptInfo *grouped_rel;
3914
3915 if (IS_OTHER_REL(input_rel))
3916 {
3917 grouped_rel = fetch_upper_rel(root, UPPERREL_GROUP_AGG,
3918 input_rel->relids);
3919 grouped_rel->reloptkind = RELOPT_OTHER_UPPER_REL;
3920 }
3921 else
3922 {
3923 /*
3924 * By tradition, the relids set for the main grouping relation is
3925 * NULL. (This could be changed, but might require adjustments
3926 * elsewhere.)
3927 */
3928 grouped_rel = fetch_upper_rel(root, UPPERREL_GROUP_AGG, NULL);
3929 }
3930
3931 /* Set target. */
3932 grouped_rel->reltarget = target;
3933
3934 /*
3935 * If the input relation is not parallel-safe, then the grouped relation
3936 * can't be parallel-safe, either. Otherwise, it's parallel-safe if the
3937 * target list and HAVING quals are parallel-safe.
3938 */
3939 if (input_rel->consider_parallel && target_parallel_safe &&
3940 is_parallel_safe(root, (Node *) havingQual))
3941 grouped_rel->consider_parallel = true;
3942
3943 /*
3944 * If the input rel belongs to a single FDW, so does the grouped rel.
3945 */
3946 grouped_rel->serverid = input_rel->serverid;
3947 grouped_rel->userid = input_rel->userid;
3948 grouped_rel->useridiscurrent = input_rel->useridiscurrent;
3949 grouped_rel->fdwroutine = input_rel->fdwroutine;
3950
3951 return grouped_rel;
3952}
3953
3954/*
3955 * is_degenerate_grouping
3956 *
3957 * A degenerate grouping is one in which the query has a HAVING qual and/or
3958 * grouping sets, but no aggregates and no GROUP BY (which implies that the
3959 * grouping sets are all empty).
3960 */
3961static bool
3962is_degenerate_grouping(PlannerInfo *root)
3963{
3964 Query *parse = root->parse;
3965
3966 return (root->hasHavingQual || parse->groupingSets) &&
3967 !parse->hasAggs && parse->groupClause == NIL;
3968}
3969
3970/*
3971 * create_degenerate_grouping_paths
3972 *
3973 * When the grouping is degenerate (see is_degenerate_grouping), we are
3974 * supposed to emit either zero or one row for each grouping set depending on
3975 * whether HAVING succeeds. Furthermore, there cannot be any variables in
3976 * either HAVING or the targetlist, so we actually do not need the FROM table
3977 * at all! We can just throw away the plan-so-far and generate a Result node.
3978 * This is a sufficiently unusual corner case that it's not worth contorting
3979 * the structure of this module to avoid having to generate the earlier paths
3980 * in the first place.
3981 */
3982static void
3983create_degenerate_grouping_paths(PlannerInfo *root, RelOptInfo *input_rel,
3984 RelOptInfo *grouped_rel)
3985{
3986 Query *parse = root->parse;
3987 int nrows;
3988 Path *path;
3989
3990 nrows = list_length(parse->groupingSets);
3991 if (nrows > 1)
3992 {
3993 /*
3994 * Doesn't seem worthwhile writing code to cons up a generate_series
3995 * or a values scan to emit multiple rows. Instead just make N clones
3996 * and append them. (With a volatile HAVING clause, this means you
3997 * might get between 0 and N output rows. Offhand I think that's
3998 * desired.)
3999 */
4000 List *paths = NIL;
4001
4002 while (--nrows >= 0)
4003 {
4004 path = (Path *)
4005 create_group_result_path(root, grouped_rel,
4006 grouped_rel->reltarget,
4007 (List *) parse->havingQual);
4008 paths = lappend(paths, path);
4009 }
4010 path = (Path *)
4011 create_append_path(root,
4012 grouped_rel,
4013 paths,
4014 NIL,
4015 NIL,
4016 NULL,
4017 0,
4018 false,
4019 NIL,
4020 -1);
4021 }
4022 else
4023 {
4024 /* No grouping sets, or just one, so one output row */
4025 path = (Path *)
4026 create_group_result_path(root, grouped_rel,
4027 grouped_rel->reltarget,
4028 (List *) parse->havingQual);
4029 }
4030
4031 add_path(grouped_rel, path);
4032}
4033
4034/*
4035 * create_ordinary_grouping_paths
4036 *
4037 * Create grouping paths for the ordinary (that is, non-degenerate) case.
4038 *
4039 * We need to consider sorted and hashed aggregation in the same function,
4040 * because otherwise (1) it would be harder to throw an appropriate error
4041 * message if neither way works, and (2) we should not allow hashtable size
4042 * considerations to dissuade us from using hashing if sorting is not possible.
4043 *
4044 * *partially_grouped_rel_p will be set to the partially grouped rel which this
4045 * function creates, or to NULL if it doesn't create one.
4046 */
4047static void
4048create_ordinary_grouping_paths(PlannerInfo *root, RelOptInfo *input_rel,
4049 RelOptInfo *grouped_rel,
4050 const AggClauseCosts *agg_costs,
4051 grouping_sets_data *gd,
4052 GroupPathExtraData *extra,
4053 RelOptInfo **partially_grouped_rel_p)
4054{
4055 Path *cheapest_path = input_rel->cheapest_total_path;
4056 RelOptInfo *partially_grouped_rel = NULL;
4057 double dNumGroups;
4058 PartitionwiseAggregateType patype = PARTITIONWISE_AGGREGATE_NONE;
4059
4060 /*
4061 * If this is the topmost grouping relation or if the parent relation is
4062 * doing some form of partitionwise aggregation, then we may be able to do
4063 * it at this level also. However, if the input relation is not
4064 * partitioned, partitionwise aggregate is impossible.
4065 */
4066 if (extra->patype != PARTITIONWISE_AGGREGATE_NONE &&
4067 IS_PARTITIONED_REL(input_rel))
4068 {
4069 /*
4070 * If this is the topmost relation or if the parent relation is doing
4071 * full partitionwise aggregation, then we can do full partitionwise
4072 * aggregation provided that the GROUP BY clause contains all of the
4073 * partitioning columns at this level. Otherwise, we can do at most
4074 * partial partitionwise aggregation. But if partial aggregation is
4075 * not supported in general then we can't use it for partitionwise
4076 * aggregation either.
4077 */
4078 if (extra->patype == PARTITIONWISE_AGGREGATE_FULL &&
4079 group_by_has_partkey(input_rel, extra->targetList,
4080 root->parse->groupClause))
4081 patype = PARTITIONWISE_AGGREGATE_FULL;
4082 else if ((extra->flags & GROUPING_CAN_PARTIAL_AGG) != 0)
4083 patype = PARTITIONWISE_AGGREGATE_PARTIAL;
4084 else
4085 patype = PARTITIONWISE_AGGREGATE_NONE;
4086 }
4087
4088 /*
4089 * Before generating paths for grouped_rel, we first generate any possible
4090 * partially grouped paths; that way, later code can easily consider both
4091 * parallel and non-parallel approaches to grouping.
4092 */
4093 if ((extra->flags & GROUPING_CAN_PARTIAL_AGG) != 0)
4094 {
4095 bool force_rel_creation;
4096
4097 /*
4098 * If we're doing partitionwise aggregation at this level, force
4099 * creation of a partially_grouped_rel so we can add partitionwise
4100 * paths to it.
4101 */
4102 force_rel_creation = (patype == PARTITIONWISE_AGGREGATE_PARTIAL);
4103
4104 partially_grouped_rel =
4105 create_partial_grouping_paths(root,
4106 grouped_rel,
4107 input_rel,
4108 gd,
4109 extra,
4110 force_rel_creation);
4111 }
4112
4113 /* Set out parameter. */
4114 *partially_grouped_rel_p = partially_grouped_rel;
4115
4116 /* Apply partitionwise aggregation technique, if possible. */
4117 if (patype != PARTITIONWISE_AGGREGATE_NONE)
4118 create_partitionwise_grouping_paths(root, input_rel, grouped_rel,
4119 partially_grouped_rel, agg_costs,
4120 gd, patype, extra);
4121
4122 /* If we are doing partial aggregation only, return. */
4123 if (extra->patype == PARTITIONWISE_AGGREGATE_PARTIAL)
4124 {
4125 Assert(partially_grouped_rel);
4126
4127 if (partially_grouped_rel->pathlist)
4128 set_cheapest(partially_grouped_rel);
4129
4130 return;
4131 }
4132
4133 /* Gather any partially grouped partial paths. */
4134 if (partially_grouped_rel && partially_grouped_rel->partial_pathlist)
4135 {
4136 gather_grouping_paths(root, partially_grouped_rel);
4137 set_cheapest(partially_grouped_rel);
4138 }
4139
4140 /*
4141 * Estimate number of groups.
4142 */
4143 dNumGroups = get_number_of_groups(root,
4144 cheapest_path->rows,
4145 gd,
4146 extra->targetList);
4147
4148 /* Build final grouping paths */
4149 add_paths_to_grouping_rel(root, input_rel, grouped_rel,
4150 partially_grouped_rel, agg_costs, gd,
4151 dNumGroups, extra);
4152
4153 /* Give a helpful error if we failed to find any implementation */
4154 if (grouped_rel->pathlist == NIL)
4155 ereport(ERROR,
4156 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4157 errmsg("could not implement GROUP BY"),
4158 errdetail("Some of the datatypes only support hashing, while others only support sorting.")));
4159
4160 /*
4161 * If there is an FDW that's responsible for all baserels of the query,
4162 * let it consider adding ForeignPaths.
4163 */
4164 if (grouped_rel->fdwroutine &&
4165 grouped_rel->fdwroutine->GetForeignUpperPaths)
4166 grouped_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_GROUP_AGG,
4167 input_rel, grouped_rel,
4168 extra);
4169
4170 /* Let extensions possibly add some more paths */
4171 if (create_upper_paths_hook)
4172 (*create_upper_paths_hook) (root, UPPERREL_GROUP_AGG,
4173 input_rel, grouped_rel,
4174 extra);
4175}
4176
4177/*
4178 * For a given input path, consider the possible ways of doing grouping sets on
4179 * it, by combinations of hashing and sorting. This can be called multiple
4180 * times, so it's important that it not scribble on input. No result is
4181 * returned, but any generated paths are added to grouped_rel.
4182 */
4183static void
4184consider_groupingsets_paths(PlannerInfo *root,
4185 RelOptInfo *grouped_rel,
4186 Path *path,
4187 bool is_sorted,
4188 bool can_hash,
4189 grouping_sets_data *gd,
4190 const AggClauseCosts *agg_costs,
4191 double dNumGroups)
4192{
4193 Query *parse = root->parse;
4194
4195 /*
4196 * If we're not being offered sorted input, then only consider plans that
4197 * can be done entirely by hashing.
4198 *
4199 * We can hash everything if it looks like it'll fit in work_mem. But if
4200 * the input is actually sorted despite not being advertised as such, we
4201 * prefer to make use of that in order to use less memory.
4202 *
4203 * If none of the grouping sets are sortable, then ignore the work_mem
4204 * limit and generate a path anyway, since otherwise we'll just fail.
4205 */
4206 if (!is_sorted)
4207 {
4208 List *new_rollups = NIL;
4209 RollupData *unhashed_rollup = NULL;
4210 List *sets_data;
4211 List *empty_sets_data = NIL;
4212 List *empty_sets = NIL;
4213 ListCell *lc;
4214 ListCell *l_start = list_head(gd->rollups);
4215 AggStrategy strat = AGG_HASHED;
4216 double hashsize;
4217 double exclude_groups = 0.0;
4218
4219 Assert(can_hash);
4220
4221 /*
4222 * If the input is coincidentally sorted usefully (which can happen
4223 * even if is_sorted is false, since that only means that our caller
4224 * has set up the sorting for us), then save some hashtable space by
4225 * making use of that. But we need to watch out for degenerate cases:
4226 *
4227 * 1) If there are any empty grouping sets, then group_pathkeys might
4228 * be NIL if all non-empty grouping sets are unsortable. In this case,
4229 * there will be a rollup containing only empty groups, and the
4230 * pathkeys_contained_in test is vacuously true; this is ok.
4231 *
4232 * XXX: the above relies on the fact that group_pathkeys is generated
4233 * from the first rollup. If we add the ability to consider multiple
4234 * sort orders for grouping input, this assumption might fail.
4235 *
4236 * 2) If there are no empty sets and only unsortable sets, then the
4237 * rollups list will be empty (and thus l_start == NULL), and
4238 * group_pathkeys will be NIL; we must ensure that the vacuously-true
4239 * pathkeys_contain_in test doesn't cause us to crash.
4240 */
4241 if (l_start != NULL &&
4242 pathkeys_contained_in(root->group_pathkeys, path->pathkeys))
4243 {
4244 unhashed_rollup = lfirst_node(RollupData, l_start);
4245 exclude_groups = unhashed_rollup->numGroups;
4246 l_start = lnext(l_start);
4247 }
4248
4249 hashsize = estimate_hashagg_tablesize(path,
4250 agg_costs,
4251 dNumGroups - exclude_groups);
4252
4253 /*
4254 * gd->rollups is empty if we have only unsortable columns to work
4255 * with. Override work_mem in that case; otherwise, we'll rely on the
4256 * sorted-input case to generate usable mixed paths.
4257 */
4258 if (hashsize > work_mem * 1024L && gd->rollups)
4259 return; /* nope, won't fit */
4260
4261 /*
4262 * We need to burst the existing rollups list into individual grouping
4263 * sets and recompute a groupClause for each set.
4264 */
4265 sets_data = list_copy(gd->unsortable_sets);
4266
4267 for_each_cell(lc, l_start)
4268 {
4269 RollupData *rollup = lfirst_node(RollupData, lc);
4270
4271 /*
4272 * If we find an unhashable rollup that's not been skipped by the
4273 * "actually sorted" check above, we can't cope; we'd need sorted
4274 * input (with a different sort order) but we can't get that here.
4275 * So bail out; we'll get a valid path from the is_sorted case
4276 * instead.
4277 *
4278 * The mere presence of empty grouping sets doesn't make a rollup
4279 * unhashable (see preprocess_grouping_sets), we handle those
4280 * specially below.
4281 */
4282 if (!rollup->hashable)
4283 return;
4284 else
4285 sets_data = list_concat(sets_data, list_copy(rollup->gsets_data));
4286 }
4287 foreach(lc, sets_data)
4288 {
4289 GroupingSetData *gs = lfirst_node(GroupingSetData, lc);
4290 List *gset = gs->set;
4291 RollupData *rollup;
4292
4293 if (gset == NIL)
4294 {
4295 /* Empty grouping sets can't be hashed. */
4296 empty_sets_data = lappend(empty_sets_data, gs);
4297 empty_sets = lappend(empty_sets, NIL);
4298 }
4299 else
4300 {
4301 rollup = makeNode(RollupData);
4302
4303 rollup->groupClause = preprocess_groupclause(root, gset);
4304 rollup->gsets_data = list_make1(gs);
4305 rollup->gsets = remap_to_groupclause_idx(rollup->groupClause,
4306 rollup->gsets_data,
4307 gd->tleref_to_colnum_map);
4308 rollup->numGroups = gs->numGroups;
4309 rollup->hashable = true;
4310 rollup->is_hashed = true;
4311 new_rollups = lappend(new_rollups, rollup);
4312 }
4313 }
4314
4315 /*
4316 * If we didn't find anything nonempty to hash, then bail. We'll
4317 * generate a path from the is_sorted case.
4318 */
4319 if (new_rollups == NIL)
4320 return;
4321
4322 /*
4323 * If there were empty grouping sets they should have been in the
4324 * first rollup.
4325 */
4326 Assert(!unhashed_rollup || !empty_sets);
4327
4328 if (unhashed_rollup)
4329 {
4330 new_rollups = lappend(new_rollups, unhashed_rollup);
4331 strat = AGG_MIXED;
4332 }
4333 else if (empty_sets)
4334 {
4335 RollupData *rollup = makeNode(RollupData);
4336
4337 rollup->groupClause = NIL;
4338 rollup->gsets_data = empty_sets_data;
4339 rollup->gsets = empty_sets;
4340 rollup->numGroups = list_length(empty_sets);
4341 rollup->hashable = false;
4342 rollup->is_hashed = false;
4343 new_rollups = lappend(new_rollups, rollup);
4344 strat = AGG_MIXED;
4345 }
4346
4347 add_path(grouped_rel, (Path *)
4348 create_groupingsets_path(root,
4349 grouped_rel,
4350 path,
4351 (List *) parse->havingQual,
4352 strat,
4353 new_rollups,
4354 agg_costs,
4355 dNumGroups));
4356 return;
4357 }
4358
4359 /*
4360 * If we have sorted input but nothing we can do with it, bail.
4361 */
4362 if (list_length(gd->rollups) == 0)
4363 return;
4364
4365 /*
4366 * Given sorted input, we try and make two paths: one sorted and one mixed
4367 * sort/hash. (We need to try both because hashagg might be disabled, or
4368 * some columns might not be sortable.)
4369 *
4370 * can_hash is passed in as false if some obstacle elsewhere (such as
4371 * ordered aggs) means that we shouldn't consider hashing at all.
4372 */
4373 if (can_hash && gd->any_hashable)
4374 {
4375 List *rollups = NIL;
4376 List *hash_sets = list_copy(gd->unsortable_sets);
4377 double availspace = (work_mem * 1024.0);
4378 ListCell *lc;
4379
4380 /*
4381 * Account first for space needed for groups we can't sort at all.
4382 */
4383 availspace -= estimate_hashagg_tablesize(path,
4384 agg_costs,
4385 gd->dNumHashGroups);
4386
4387 if (availspace > 0 && list_length(gd->rollups) > 1)
4388 {
4389 double scale;
4390 int num_rollups = list_length(gd->rollups);
4391 int k_capacity;
4392 int *k_weights = palloc(num_rollups * sizeof(int));
4393 Bitmapset *hash_items = NULL;
4394 int i;
4395
4396 /*
4397 * We treat this as a knapsack problem: the knapsack capacity
4398 * represents work_mem, the item weights are the estimated memory
4399 * usage of the hashtables needed to implement a single rollup,
4400 * and we really ought to use the cost saving as the item value;
4401 * however, currently the costs assigned to sort nodes don't
4402 * reflect the comparison costs well, and so we treat all items as
4403 * of equal value (each rollup we hash instead saves us one sort).
4404 *
4405 * To use the discrete knapsack, we need to scale the values to a
4406 * reasonably small bounded range. We choose to allow a 5% error
4407 * margin; we have no more than 4096 rollups in the worst possible
4408 * case, which with a 5% error margin will require a bit over 42MB
4409 * of workspace. (Anyone wanting to plan queries that complex had
4410 * better have the memory for it. In more reasonable cases, with
4411 * no more than a couple of dozen rollups, the memory usage will
4412 * be negligible.)
4413 *
4414 * k_capacity is naturally bounded, but we clamp the values for
4415 * scale and weight (below) to avoid overflows or underflows (or
4416 * uselessly trying to use a scale factor less than 1 byte).
4417 */
4418 scale = Max(availspace / (20.0 * num_rollups), 1.0);
4419 k_capacity = (int) floor(availspace / scale);
4420
4421 /*
4422 * We leave the first rollup out of consideration since it's the
4423 * one that matches the input sort order. We assign indexes "i"
4424 * to only those entries considered for hashing; the second loop,
4425 * below, must use the same condition.
4426 */
4427 i = 0;
4428 for_each_cell(lc, lnext(list_head(gd->rollups)))
4429 {
4430 RollupData *rollup = lfirst_node(RollupData, lc);
4431
4432 if (rollup->hashable)
4433 {
4434 double sz = estimate_hashagg_tablesize(path,
4435 agg_costs,
4436 rollup->numGroups);
4437
4438 /*
4439 * If sz is enormous, but work_mem (and hence scale) is
4440 * small, avoid integer overflow here.
4441 */
4442 k_weights[i] = (int) Min(floor(sz / scale),
4443 k_capacity + 1.0);
4444 ++i;
4445 }
4446 }
4447
4448 /*
4449 * Apply knapsack algorithm; compute the set of items which
4450 * maximizes the value stored (in this case the number of sorts
4451 * saved) while keeping the total size (approximately) within
4452 * capacity.
4453 */
4454 if (i > 0)
4455 hash_items = DiscreteKnapsack(k_capacity, i, k_weights, NULL);
4456
4457 if (!bms_is_empty(hash_items))
4458 {
4459 rollups = list_make1(linitial(gd->rollups));
4460
4461 i = 0;
4462 for_each_cell(lc, lnext(list_head(gd->rollups)))
4463 {
4464 RollupData *rollup = lfirst_node(RollupData, lc);
4465
4466 if (rollup->hashable)
4467 {
4468 if (bms_is_member(i, hash_items))
4469 hash_sets = list_concat(hash_sets,
4470 list_copy(rollup->gsets_data));
4471 else
4472 rollups = lappend(rollups, rollup);
4473 ++i;
4474 }
4475 else
4476 rollups = lappend(rollups, rollup);
4477 }
4478 }
4479 }
4480
4481 if (!rollups && hash_sets)
4482 rollups = list_copy(gd->rollups);
4483
4484 foreach(lc, hash_sets)
4485 {
4486 GroupingSetData *gs = lfirst_node(GroupingSetData, lc);
4487 RollupData *rollup = makeNode(RollupData);
4488
4489 Assert(gs->set != NIL);
4490
4491 rollup->groupClause = preprocess_groupclause(root, gs->set);
4492 rollup->gsets_data = list_make1(gs);
4493 rollup->gsets = remap_to_groupclause_idx(rollup->groupClause,
4494 rollup->gsets_data,
4495 gd->tleref_to_colnum_map);
4496 rollup->numGroups = gs->numGroups;
4497 rollup->hashable = true;
4498 rollup->is_hashed = true;
4499 rollups = lcons(rollup, rollups);
4500 }
4501
4502 if (rollups)
4503 {
4504 add_path(grouped_rel, (Path *)
4505 create_groupingsets_path(root,
4506 grouped_rel,
4507 path,
4508 (List *) parse->havingQual,
4509 AGG_MIXED,
4510 rollups,
4511 agg_costs,
4512 dNumGroups));
4513 }
4514 }
4515
4516 /*
4517 * Now try the simple sorted case.
4518 */
4519 if (!gd->unsortable_sets)
4520 add_path(grouped_rel, (Path *)
4521 create_groupingsets_path(root,
4522 grouped_rel,
4523 path,
4524 (List *) parse->havingQual,
4525 AGG_SORTED,
4526 gd->rollups,
4527 agg_costs,
4528 dNumGroups));
4529}
4530
4531/*
4532 * create_window_paths
4533 *
4534 * Build a new upperrel containing Paths for window-function evaluation.
4535 *
4536 * input_rel: contains the source-data Paths
4537 * input_target: result of make_window_input_target
4538 * output_target: what the topmost WindowAggPath should return
4539 * wflists: result of find_window_functions
4540 * activeWindows: result of select_active_windows
4541 *
4542 * Note: all Paths in input_rel are expected to return input_target.
4543 */
4544static RelOptInfo *
4545create_window_paths(PlannerInfo *root,
4546 RelOptInfo *input_rel,
4547 PathTarget *input_target,
4548 PathTarget *output_target,
4549 bool output_target_parallel_safe,
4550 WindowFuncLists *wflists,
4551 List *activeWindows)
4552{
4553 RelOptInfo *window_rel;
4554 ListCell *lc;
4555
4556 /* For now, do all work in the (WINDOW, NULL) upperrel */
4557 window_rel = fetch_upper_rel(root, UPPERREL_WINDOW, NULL);
4558
4559 /*
4560 * If the input relation is not parallel-safe, then the window relation
4561 * can't be parallel-safe, either. Otherwise, we need to examine the
4562 * target list and active windows for non-parallel-safe constructs.
4563 */
4564 if (input_rel->consider_parallel && output_target_parallel_safe &&
4565 is_parallel_safe(root, (Node *) activeWindows))
4566 window_rel->consider_parallel = true;
4567
4568 /*
4569 * If the input rel belongs to a single FDW, so does the window rel.
4570 */
4571 window_rel->serverid = input_rel->serverid;
4572 window_rel->userid = input_rel->userid;
4573 window_rel->useridiscurrent = input_rel->useridiscurrent;
4574 window_rel->fdwroutine = input_rel->fdwroutine;
4575
4576 /*
4577 * Consider computing window functions starting from the existing
4578 * cheapest-total path (which will likely require a sort) as well as any
4579 * existing paths that satisfy root->window_pathkeys (which won't).
4580 */
4581 foreach(lc, input_rel->pathlist)
4582 {
4583 Path *path = (Path *) lfirst(lc);
4584
4585 if (path == input_rel->cheapest_total_path ||
4586 pathkeys_contained_in(root->window_pathkeys, path->pathkeys))
4587 create_one_window_path(root,
4588 window_rel,
4589 path,
4590 input_target,
4591 output_target,
4592 wflists,
4593 activeWindows);
4594 }
4595
4596 /*
4597 * If there is an FDW that's responsible for all baserels of the query,
4598 * let it consider adding ForeignPaths.
4599 */
4600 if (window_rel->fdwroutine &&
4601 window_rel->fdwroutine->GetForeignUpperPaths)
4602 window_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_WINDOW,
4603 input_rel, window_rel,
4604 NULL);
4605
4606 /* Let extensions possibly add some more paths */
4607 if (create_upper_paths_hook)
4608 (*create_upper_paths_hook) (root, UPPERREL_WINDOW,
4609 input_rel, window_rel, NULL);
4610
4611 /* Now choose the best path(s) */
4612 set_cheapest(window_rel);
4613
4614 return window_rel;
4615}
4616
4617/*
4618 * Stack window-function implementation steps atop the given Path, and
4619 * add the result to window_rel.
4620 *
4621 * window_rel: upperrel to contain result
4622 * path: input Path to use (must return input_target)
4623 * input_target: result of make_window_input_target
4624 * output_target: what the topmost WindowAggPath should return
4625 * wflists: result of find_window_functions
4626 * activeWindows: result of select_active_windows
4627 */
4628static void
4629create_one_window_path(PlannerInfo *root,
4630 RelOptInfo *window_rel,
4631 Path *path,
4632 PathTarget *input_target,
4633 PathTarget *output_target,
4634 WindowFuncLists *wflists,
4635 List *activeWindows)
4636{
4637 PathTarget *window_target;
4638 ListCell *l;
4639
4640 /*
4641 * Since each window clause could require a different sort order, we stack
4642 * up a WindowAgg node for each clause, with sort steps between them as
4643 * needed. (We assume that select_active_windows chose a good order for
4644 * executing the clauses in.)
4645 *
4646 * input_target should contain all Vars and Aggs needed for the result.
4647 * (In some cases we wouldn't need to propagate all of these all the way
4648 * to the top, since they might only be needed as inputs to WindowFuncs.
4649 * It's probably not worth trying to optimize that though.) It must also
4650 * contain all window partitioning and sorting expressions, to ensure
4651 * they're computed only once at the bottom of the stack (that's critical
4652 * for volatile functions). As we climb up the stack, we'll add outputs
4653 * for the WindowFuncs computed at each level.
4654 */
4655 window_target = input_target;
4656
4657 foreach(l, activeWindows)
4658 {
4659 WindowClause *wc = lfirst_node(WindowClause, l);
4660 List *window_pathkeys;
4661
4662 window_pathkeys = make_pathkeys_for_window(root,
4663 wc,
4664 root->processed_tlist);
4665
4666 /* Sort if necessary */
4667 if (!pathkeys_contained_in(window_pathkeys, path->pathkeys))
4668 {
4669 path = (Path *) create_sort_path(root, window_rel,
4670 path,
4671 window_pathkeys,
4672 -1.0);
4673 }
4674
4675 if (lnext(l))
4676 {
4677 /*
4678 * Add the current WindowFuncs to the output target for this
4679 * intermediate WindowAggPath. We must copy window_target to
4680 * avoid changing the previous path's target.
4681 *
4682 * Note: a WindowFunc adds nothing to the target's eval costs; but
4683 * we do need to account for the increase in tlist width.
4684 */
4685 ListCell *lc2;
4686
4687 window_target = copy_pathtarget(window_target);
4688 foreach(lc2, wflists->windowFuncs[wc->winref])
4689 {
4690 WindowFunc *wfunc = lfirst_node(WindowFunc, lc2);
4691
4692 add_column_to_pathtarget(window_target, (Expr *) wfunc, 0);
4693 window_target->width += get_typavgwidth(wfunc->wintype, -1);
4694 }
4695 }
4696 else
4697 {
4698 /* Install the goal target in the topmost WindowAgg */
4699 window_target = output_target;
4700 }
4701
4702 path = (Path *)
4703 create_windowagg_path(root, window_rel, path, window_target,
4704 wflists->windowFuncs[wc->winref],
4705 wc);
4706 }
4707
4708 add_path(window_rel, path);
4709}
4710
4711/*
4712 * create_distinct_paths
4713 *
4714 * Build a new upperrel containing Paths for SELECT DISTINCT evaluation.
4715 *
4716 * input_rel: contains the source-data Paths
4717 *
4718 * Note: input paths should already compute the desired pathtarget, since
4719 * Sort/Unique won't project anything.
4720 */
4721static RelOptInfo *
4722create_distinct_paths(PlannerInfo *root,
4723 RelOptInfo *input_rel)
4724{
4725 Query *parse = root->parse;
4726 Path *cheapest_input_path = input_rel->cheapest_total_path;
4727 RelOptInfo *distinct_rel;
4728 double numDistinctRows;
4729 bool allow_hash;
4730 Path *path;
4731 ListCell *lc;
4732
4733 /* For now, do all work in the (DISTINCT, NULL) upperrel */
4734 distinct_rel = fetch_upper_rel(root, UPPERREL_DISTINCT, NULL);
4735
4736 /*
4737 * We don't compute anything at this level, so distinct_rel will be
4738 * parallel-safe if the input rel is parallel-safe. In particular, if
4739 * there is a DISTINCT ON (...) clause, any path for the input_rel will
4740 * output those expressions, and will not be parallel-safe unless those
4741 * expressions are parallel-safe.
4742 */
4743 distinct_rel->consider_parallel = input_rel->consider_parallel;
4744
4745 /*
4746 * If the input rel belongs to a single FDW, so does the distinct_rel.
4747 */
4748 distinct_rel->serverid = input_rel->serverid;
4749 distinct_rel->userid = input_rel->userid;
4750 distinct_rel->useridiscurrent = input_rel->useridiscurrent;
4751 distinct_rel->fdwroutine = input_rel->fdwroutine;
4752
4753 /* Estimate number of distinct rows there will be */
4754 if (parse->groupClause || parse->groupingSets || parse->hasAggs ||
4755 root->hasHavingQual)
4756 {
4757 /*
4758 * If there was grouping or aggregation, use the number of input rows
4759 * as the estimated number of DISTINCT rows (ie, assume the input is
4760 * already mostly unique).
4761 */
4762 numDistinctRows = cheapest_input_path->rows;
4763 }
4764 else
4765 {
4766 /*
4767 * Otherwise, the UNIQUE filter has effects comparable to GROUP BY.
4768 */
4769 List *distinctExprs;
4770
4771 distinctExprs = get_sortgrouplist_exprs(parse->distinctClause,
4772 parse->targetList);
4773 numDistinctRows = estimate_num_groups(root, distinctExprs,
4774 cheapest_input_path->rows,
4775 NULL);
4776 }
4777
4778 /*
4779 * Consider sort-based implementations of DISTINCT, if possible.
4780 */
4781 if (grouping_is_sortable(parse->distinctClause))
4782 {
4783 /*
4784 * First, if we have any adequately-presorted paths, just stick a
4785 * Unique node on those. Then consider doing an explicit sort of the
4786 * cheapest input path and Unique'ing that.
4787 *
4788 * When we have DISTINCT ON, we must sort by the more rigorous of
4789 * DISTINCT and ORDER BY, else it won't have the desired behavior.
4790 * Also, if we do have to do an explicit sort, we might as well use
4791 * the more rigorous ordering to avoid a second sort later. (Note
4792 * that the parser will have ensured that one clause is a prefix of
4793 * the other.)
4794 */
4795 List *needed_pathkeys;
4796
4797 if (parse->hasDistinctOn &&
4798 list_length(root->distinct_pathkeys) <
4799 list_length(root->sort_pathkeys))
4800 needed_pathkeys = root->sort_pathkeys;
4801 else
4802 needed_pathkeys = root->distinct_pathkeys;
4803
4804 foreach(lc, input_rel->pathlist)
4805 {
4806 Path *path = (Path *) lfirst(lc);
4807
4808 if (pathkeys_contained_in(needed_pathkeys, path->pathkeys))
4809 {
4810 add_path(distinct_rel, (Path *)
4811 create_upper_unique_path(root, distinct_rel,
4812 path,
4813 list_length(root->distinct_pathkeys),
4814 numDistinctRows));
4815 }
4816 }
4817
4818 /* For explicit-sort case, always use the more rigorous clause */
4819 if (list_length(root->distinct_pathkeys) <
4820 list_length(root->sort_pathkeys))
4821 {
4822 needed_pathkeys = root->sort_pathkeys;
4823 /* Assert checks that parser didn't mess up... */
4824 Assert(pathkeys_contained_in(root->distinct_pathkeys,
4825 needed_pathkeys));
4826 }
4827 else
4828 needed_pathkeys = root->distinct_pathkeys;
4829
4830 path = cheapest_input_path;
4831 if (!pathkeys_contained_in(needed_pathkeys, path->pathkeys))
4832 path = (Path *) create_sort_path(root, distinct_rel,
4833 path,
4834 needed_pathkeys,
4835 -1.0);
4836
4837 add_path(distinct_rel, (Path *)
4838 create_upper_unique_path(root, distinct_rel,
4839 path,
4840 list_length(root->distinct_pathkeys),
4841 numDistinctRows));
4842 }
4843
4844 /*
4845 * Consider hash-based implementations of DISTINCT, if possible.
4846 *
4847 * If we were not able to make any other types of path, we *must* hash or
4848 * die trying. If we do have other choices, there are several things that
4849 * should prevent selection of hashing: if the query uses DISTINCT ON
4850 * (because it won't really have the expected behavior if we hash), or if
4851 * enable_hashagg is off, or if it looks like the hashtable will exceed
4852 * work_mem.
4853 *
4854 * Note: grouping_is_hashable() is much more expensive to check than the
4855 * other gating conditions, so we want to do it last.
4856 */
4857 if (distinct_rel->pathlist == NIL)
4858 allow_hash = true; /* we have no alternatives */
4859 else if (parse->hasDistinctOn || !enable_hashagg)
4860 allow_hash = false; /* policy-based decision not to hash */
4861 else
4862 {
4863 Size hashentrysize;
4864
4865 /* Estimate per-hash-entry space at tuple width... */
4866 hashentrysize = MAXALIGN(cheapest_input_path->pathtarget->width) +
4867 MAXALIGN(SizeofMinimalTupleHeader);
4868 /* plus the per-hash-entry overhead */
4869 hashentrysize += hash_agg_entry_size(0);
4870
4871 /* Allow hashing only if hashtable is predicted to fit in work_mem */
4872 allow_hash = (hashentrysize * numDistinctRows <= work_mem * 1024L);
4873 }
4874
4875 if (allow_hash && grouping_is_hashable(parse->distinctClause))
4876 {
4877 /* Generate hashed aggregate path --- no sort needed */
4878 add_path(distinct_rel, (Path *)
4879 create_agg_path(root,
4880 distinct_rel,
4881 cheapest_input_path,
4882 cheapest_input_path->pathtarget,
4883 AGG_HASHED,
4884 AGGSPLIT_SIMPLE,
4885 parse->distinctClause,
4886 NIL,
4887 NULL,
4888 numDistinctRows));
4889 }
4890
4891 /* Give a helpful error if we failed to find any implementation */
4892 if (distinct_rel->pathlist == NIL)
4893 ereport(ERROR,
4894 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
4895 errmsg("could not implement DISTINCT"),
4896 errdetail("Some of the datatypes only support hashing, while others only support sorting.")));
4897
4898 /*
4899 * If there is an FDW that's responsible for all baserels of the query,
4900 * let it consider adding ForeignPaths.
4901 */
4902 if (distinct_rel->fdwroutine &&
4903 distinct_rel->fdwroutine->GetForeignUpperPaths)
4904 distinct_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_DISTINCT,
4905 input_rel, distinct_rel,
4906 NULL);
4907
4908 /* Let extensions possibly add some more paths */
4909 if (create_upper_paths_hook)
4910 (*create_upper_paths_hook) (root, UPPERREL_DISTINCT,
4911 input_rel, distinct_rel, NULL);
4912
4913 /* Now choose the best path(s) */
4914 set_cheapest(distinct_rel);
4915
4916 return distinct_rel;
4917}
4918
4919/*
4920 * create_ordered_paths
4921 *
4922 * Build a new upperrel containing Paths for ORDER BY evaluation.
4923 *
4924 * All paths in the result must satisfy the ORDER BY ordering.
4925 * The only new path we need consider is an explicit sort on the
4926 * cheapest-total existing path.
4927 *
4928 * input_rel: contains the source-data Paths
4929 * target: the output tlist the result Paths must emit
4930 * limit_tuples: estimated bound on the number of output tuples,
4931 * or -1 if no LIMIT or couldn't estimate
4932 */
4933static RelOptInfo *
4934create_ordered_paths(PlannerInfo *root,
4935 RelOptInfo *input_rel,
4936 PathTarget *target,
4937 bool target_parallel_safe,
4938 double limit_tuples)
4939{
4940 Path *cheapest_input_path = input_rel->cheapest_total_path;
4941 RelOptInfo *ordered_rel;
4942 ListCell *lc;
4943
4944 /* For now, do all work in the (ORDERED, NULL) upperrel */
4945 ordered_rel = fetch_upper_rel(root, UPPERREL_ORDERED, NULL);
4946
4947 /*
4948 * If the input relation is not parallel-safe, then the ordered relation
4949 * can't be parallel-safe, either. Otherwise, it's parallel-safe if the
4950 * target list is parallel-safe.
4951 */
4952 if (input_rel->consider_parallel && target_parallel_safe)
4953 ordered_rel->consider_parallel = true;
4954
4955 /*
4956 * If the input rel belongs to a single FDW, so does the ordered_rel.
4957 */
4958 ordered_rel->serverid = input_rel->serverid;
4959 ordered_rel->userid = input_rel->userid;
4960 ordered_rel->useridiscurrent = input_rel->useridiscurrent;
4961 ordered_rel->fdwroutine = input_rel->fdwroutine;
4962
4963 foreach(lc, input_rel->pathlist)
4964 {
4965 Path *path = (Path *) lfirst(lc);
4966 bool is_sorted;
4967
4968 is_sorted = pathkeys_contained_in(root->sort_pathkeys,
4969 path->pathkeys);
4970 if (path == cheapest_input_path || is_sorted)
4971 {
4972 if (!is_sorted)
4973 {
4974 /* An explicit sort here can take advantage of LIMIT */
4975 path = (Path *) create_sort_path(root,
4976 ordered_rel,
4977 path,
4978 root->sort_pathkeys,
4979 limit_tuples);
4980 }
4981
4982 /* Add projection step if needed */
4983 if (path->pathtarget != target)
4984 path = apply_projection_to_path(root, ordered_rel,
4985 path, target);
4986
4987 add_path(ordered_rel, path);
4988 }
4989 }
4990
4991 /*
4992 * generate_gather_paths() will have already generated a simple Gather
4993 * path for the best parallel path, if any, and the loop above will have
4994 * considered sorting it. Similarly, generate_gather_paths() will also
4995 * have generated order-preserving Gather Merge plans which can be used
4996 * without sorting if they happen to match the sort_pathkeys, and the loop
4997 * above will have handled those as well. However, there's one more
4998 * possibility: it may make sense to sort the cheapest partial path
4999 * according to the required output order and then use Gather Merge.
5000 */
5001 if (ordered_rel->consider_parallel && root->sort_pathkeys != NIL &&
5002 input_rel->partial_pathlist != NIL)
5003 {
5004 Path *cheapest_partial_path;
5005
5006 cheapest_partial_path = linitial(input_rel->partial_pathlist);
5007
5008 /*
5009 * If cheapest partial path doesn't need a sort, this is redundant
5010 * with what's already been tried.
5011 */
5012 if (!pathkeys_contained_in(root->sort_pathkeys,
5013 cheapest_partial_path->pathkeys))
5014 {
5015 Path *path;
5016 double total_groups;
5017
5018 path = (Path *) create_sort_path(root,
5019 ordered_rel,
5020 cheapest_partial_path,
5021 root->sort_pathkeys,
5022 limit_tuples);
5023
5024 total_groups = cheapest_partial_path->rows *
5025 cheapest_partial_path->parallel_workers;
5026 path = (Path *)
5027 create_gather_merge_path(root, ordered_rel,
5028 path,
5029 path->pathtarget,
5030 root->sort_pathkeys, NULL,
5031 &total_groups);
5032
5033 /* Add projection step if needed */
5034 if (path->pathtarget != target)
5035 path = apply_projection_to_path(root, ordered_rel,
5036 path, target);
5037
5038 add_path(ordered_rel, path);
5039 }
5040 }
5041
5042 /*
5043 * If there is an FDW that's responsible for all baserels of the query,
5044 * let it consider adding ForeignPaths.
5045 */
5046 if (ordered_rel->fdwroutine &&
5047 ordered_rel->fdwroutine->GetForeignUpperPaths)
5048 ordered_rel->fdwroutine->GetForeignUpperPaths(root, UPPERREL_ORDERED,
5049 input_rel, ordered_rel,
5050 NULL);
5051
5052 /* Let extensions possibly add some more paths */
5053 if (create_upper_paths_hook)
5054 (*create_upper_paths_hook) (root, UPPERREL_ORDERED,
5055 input_rel, ordered_rel, NULL);
5056
5057 /*
5058 * No need to bother with set_cheapest here; grouping_planner does not
5059 * need us to do it.
5060 */
5061 Assert(ordered_rel->pathlist != NIL);
5062
5063 return ordered_rel;
5064}
5065
5066
5067/*
5068 * make_group_input_target
5069 * Generate appropriate PathTarget for initial input to grouping nodes.
5070 *
5071 * If there is grouping or aggregation, the scan/join subplan cannot emit
5072 * the query's final targetlist; for example, it certainly can't emit any
5073 * aggregate function calls. This routine generates the correct target
5074 * for the scan/join subplan.
5075 *
5076 * The query target list passed from the parser already contains entries
5077 * for all ORDER BY and GROUP BY expressions, but it will not have entries
5078 * for variables used only in HAVING clauses; so we need to add those
5079 * variables to the subplan target list. Also, we flatten all expressions
5080 * except GROUP BY items into their component variables; other expressions
5081 * will be computed by the upper plan nodes rather than by the subplan.
5082 * For example, given a query like
5083 * SELECT a+b,SUM(c+d) FROM table GROUP BY a+b;
5084 * we want to pass this targetlist to the subplan:
5085 * a+b,c,d
5086 * where the a+b target will be used by the Sort/Group steps, and the
5087 * other targets will be used for computing the final results.
5088 *
5089 * 'final_target' is the query's final target list (in PathTarget form)
5090 *
5091 * The result is the PathTarget to be computed by the Paths returned from
5092 * query_planner().
5093 */
5094static PathTarget *
5095make_group_input_target(PlannerInfo *root, PathTarget *final_target)
5096{
5097 Query *parse = root->parse;
5098 PathTarget *input_target;
5099 List *non_group_cols;
5100 List *non_group_vars;
5101 int i;
5102 ListCell *lc;
5103
5104 /*
5105 * We must build a target containing all grouping columns, plus any other
5106 * Vars mentioned in the query's targetlist and HAVING qual.
5107 */
5108 input_target = create_empty_pathtarget();
5109 non_group_cols = NIL;
5110
5111 i = 0;
5112 foreach(lc, final_target->exprs)
5113 {
5114 Expr *expr = (Expr *) lfirst(lc);
5115 Index sgref = get_pathtarget_sortgroupref(final_target, i);
5116
5117 if (sgref && parse->groupClause &&
5118 get_sortgroupref_clause_noerr(sgref, parse->groupClause) != NULL)
5119 {
5120 /*
5121 * It's a grouping column, so add it to the input target as-is.
5122 */
5123 add_column_to_pathtarget(input_target, expr, sgref);
5124 }
5125 else
5126 {
5127 /*
5128 * Non-grouping column, so just remember the expression for later
5129 * call to pull_var_clause.
5130 */
5131 non_group_cols = lappend(non_group_cols, expr);
5132 }
5133
5134 i++;
5135 }
5136
5137 /*
5138 * If there's a HAVING clause, we'll need the Vars it uses, too.
5139 */
5140 if (parse->havingQual)
5141 non_group_cols = lappend(non_group_cols, parse->havingQual);
5142
5143 /*
5144 * Pull out all the Vars mentioned in non-group cols (plus HAVING), and
5145 * add them to the input target if not already present. (A Var used
5146 * directly as a GROUP BY item will be present already.) Note this
5147 * includes Vars used in resjunk items, so we are covering the needs of
5148 * ORDER BY and window specifications. Vars used within Aggrefs and
5149 * WindowFuncs will be pulled out here, too.
5150 */
5151 non_group_vars = pull_var_clause((Node *) non_group_cols,
5152 PVC_RECURSE_AGGREGATES |
5153 PVC_RECURSE_WINDOWFUNCS |
5154 PVC_INCLUDE_PLACEHOLDERS);
5155 add_new_columns_to_pathtarget(input_target, non_group_vars);
5156
5157 /* clean up cruft */
5158 list_free(non_group_vars);
5159 list_free(non_group_cols);
5160
5161 /* XXX this causes some redundant cost calculation ... */
5162 return set_pathtarget_cost_width(root, input_target);
5163}
5164
5165/*
5166 * make_partial_grouping_target
5167 * Generate appropriate PathTarget for output of partial aggregate
5168 * (or partial grouping, if there are no aggregates) nodes.
5169 *
5170 * A partial aggregation node needs to emit all the same aggregates that
5171 * a regular aggregation node would, plus any aggregates used in HAVING;
5172 * except that the Aggref nodes should be marked as partial aggregates.
5173 *
5174 * In addition, we'd better emit any Vars and PlaceholderVars that are
5175 * used outside of Aggrefs in the aggregation tlist and HAVING. (Presumably,
5176 * these would be Vars that are grouped by or used in grouping expressions.)
5177 *
5178 * grouping_target is the tlist to be emitted by the topmost aggregation step.
5179 * havingQual represents the HAVING clause.
5180 */
5181static PathTarget *
5182make_partial_grouping_target(PlannerInfo *root,
5183 PathTarget *grouping_target,
5184 Node *havingQual)
5185{
5186 Query *parse = root->parse;
5187 PathTarget *partial_target;
5188 List *non_group_cols;
5189 List *non_group_exprs;
5190 int i;
5191 ListCell *lc;
5192
5193 partial_target = create_empty_pathtarget();
5194 non_group_cols = NIL;
5195
5196 i = 0;
5197 foreach(lc, grouping_target->exprs)
5198 {
5199 Expr *expr = (Expr *) lfirst(lc);
5200 Index sgref = get_pathtarget_sortgroupref(grouping_target, i);
5201
5202 if (sgref && parse->groupClause &&
5203 get_sortgroupref_clause_noerr(sgref, parse->groupClause) != NULL)
5204 {
5205 /*
5206 * It's a grouping column, so add it to the partial_target as-is.
5207 * (This allows the upper agg step to repeat the grouping calcs.)
5208 */
5209 add_column_to_pathtarget(partial_target, expr, sgref);
5210 }
5211 else
5212 {
5213 /*
5214 * Non-grouping column, so just remember the expression for later
5215 * call to pull_var_clause.
5216 */
5217 non_group_cols = lappend(non_group_cols, expr);
5218 }
5219
5220 i++;
5221 }
5222
5223 /*
5224 * If there's a HAVING clause, we'll need the Vars/Aggrefs it uses, too.
5225 */
5226 if (havingQual)
5227 non_group_cols = lappend(non_group_cols, havingQual);
5228
5229 /*
5230 * Pull out all the Vars, PlaceHolderVars, and Aggrefs mentioned in
5231 * non-group cols (plus HAVING), and add them to the partial_target if not
5232 * already present. (An expression used directly as a GROUP BY item will
5233 * be present already.) Note this includes Vars used in resjunk items, so
5234 * we are covering the needs of ORDER BY and window specifications.
5235 */
5236 non_group_exprs = pull_var_clause((Node *) non_group_cols,
5237 PVC_INCLUDE_AGGREGATES |
5238 PVC_RECURSE_WINDOWFUNCS |
5239 PVC_INCLUDE_PLACEHOLDERS);
5240
5241 add_new_columns_to_pathtarget(partial_target, non_group_exprs);
5242
5243 /*
5244 * Adjust Aggrefs to put them in partial mode. At this point all Aggrefs
5245 * are at the top level of the target list, so we can just scan the list
5246 * rather than recursing through the expression trees.
5247 */
5248 foreach(lc, partial_target->exprs)
5249 {
5250 Aggref *aggref = (Aggref *) lfirst(lc);
5251
5252 if (IsA(aggref, Aggref))
5253 {
5254 Aggref *newaggref;
5255
5256 /*
5257 * We shouldn't need to copy the substructure of the Aggref node,
5258 * but flat-copy the node itself to avoid damaging other trees.
5259 */
5260 newaggref = makeNode(Aggref);
5261 memcpy(newaggref, aggref, sizeof(Aggref));
5262
5263 /* For now, assume serialization is required */
5264 mark_partial_aggref(newaggref, AGGSPLIT_INITIAL_SERIAL);
5265
5266 lfirst(lc) = newaggref;
5267 }
5268 }
5269
5270 /* clean up cruft */
5271 list_free(non_group_exprs);
5272 list_free(non_group_cols);
5273
5274 /* XXX this causes some redundant cost calculation ... */
5275 return set_pathtarget_cost_width(root, partial_target);
5276}
5277
5278/*
5279 * mark_partial_aggref
5280 * Adjust an Aggref to make it represent a partial-aggregation step.
5281 *
5282 * The Aggref node is modified in-place; caller must do any copying required.
5283 */
5284void
5285mark_partial_aggref(Aggref *agg, AggSplit aggsplit)
5286{
5287 /* aggtranstype should be computed by this point */
5288 Assert(OidIsValid(agg->aggtranstype));
5289 /* ... but aggsplit should still be as the parser left it */
5290 Assert(agg->aggsplit == AGGSPLIT_SIMPLE);
5291
5292 /* Mark the Aggref with the intended partial-aggregation mode */
5293 agg->aggsplit = aggsplit;
5294
5295 /*
5296 * Adjust result type if needed. Normally, a partial aggregate returns
5297 * the aggregate's transition type; but if that's INTERNAL and we're
5298 * serializing, it returns BYTEA instead.
5299 */
5300 if (DO_AGGSPLIT_SKIPFINAL(aggsplit))
5301 {
5302 if (agg->aggtranstype == INTERNALOID && DO_AGGSPLIT_SERIALIZE(aggsplit))
5303 agg->aggtype = BYTEAOID;
5304 else
5305 agg->aggtype = agg->aggtranstype;
5306 }
5307}
5308
5309/*
5310 * postprocess_setop_tlist
5311 * Fix up targetlist returned by plan_set_operations().
5312 *
5313 * We need to transpose sort key info from the orig_tlist into new_tlist.
5314 * NOTE: this would not be good enough if we supported resjunk sort keys
5315 * for results of set operations --- then, we'd need to project a whole
5316 * new tlist to evaluate the resjunk columns. For now, just ereport if we
5317 * find any resjunk columns in orig_tlist.
5318 */
5319static List *
5320postprocess_setop_tlist(List *new_tlist, List *orig_tlist)
5321{
5322 ListCell *l;
5323 ListCell *orig_tlist_item = list_head(orig_tlist);
5324
5325 foreach(l, new_tlist)
5326 {
5327 TargetEntry *new_tle = lfirst_node(TargetEntry, l);
5328 TargetEntry *orig_tle;
5329
5330 /* ignore resjunk columns in setop result */
5331 if (new_tle->resjunk)
5332 continue;
5333
5334 Assert(orig_tlist_item != NULL);
5335 orig_tle = lfirst_node(TargetEntry, orig_tlist_item);
5336 orig_tlist_item = lnext(orig_tlist_item);
5337 if (orig_tle->resjunk) /* should not happen */
5338 elog(ERROR, "resjunk output columns are not implemented");
5339 Assert(new_tle->resno == orig_tle->resno);
5340 new_tle->ressortgroupref = orig_tle->ressortgroupref;
5341 }
5342 if (orig_tlist_item != NULL)
5343 elog(ERROR, "resjunk output columns are not implemented");
5344 return new_tlist;
5345}
5346
5347/*
5348 * select_active_windows
5349 * Create a list of the "active" window clauses (ie, those referenced
5350 * by non-deleted WindowFuncs) in the order they are to be executed.
5351 */
5352static List *
5353select_active_windows(PlannerInfo *root, WindowFuncLists *wflists)
5354{
5355 List *windowClause = root->parse->windowClause;
5356 List *result = NIL;
5357 ListCell *lc;
5358 int nActive = 0;
5359 WindowClauseSortData *actives = palloc(sizeof(WindowClauseSortData)
5360 * list_length(windowClause));
5361
5362 /* First, construct an array of the active windows */
5363 foreach(lc, windowClause)
5364 {
5365 WindowClause *wc = lfirst_node(WindowClause, lc);
5366
5367 /* It's only active if wflists shows some related WindowFuncs */
5368 Assert(wc->winref <= wflists->maxWinRef);
5369 if (wflists->windowFuncs[wc->winref] == NIL)
5370 continue;
5371
5372 actives[nActive].wc = wc; /* original clause */
5373
5374 /*
5375 * For sorting, we want the list of partition keys followed by the
5376 * list of sort keys. But pathkeys construction will remove duplicates
5377 * between the two, so we can as well (even though we can't detect all
5378 * of the duplicates, since some may come from ECs - that might mean
5379 * we miss optimization chances here). We must, however, ensure that
5380 * the order of entries is preserved with respect to the ones we do
5381 * keep.
5382 *
5383 * partitionClause and orderClause had their own duplicates removed in
5384 * parse analysis, so we're only concerned here with removing
5385 * orderClause entries that also appear in partitionClause.
5386 */
5387 actives[nActive].uniqueOrder =
5388 list_concat_unique(list_copy(wc->partitionClause),
5389 wc->orderClause);
5390 nActive++;
5391 }
5392
5393 /*
5394 * Sort active windows by their partitioning/ordering clauses, ignoring
5395 * any framing clauses, so that the windows that need the same sorting are
5396 * adjacent in the list. When we come to generate paths, this will avoid
5397 * inserting additional Sort nodes.
5398 *
5399 * This is how we implement a specific requirement from the SQL standard,
5400 * which says that when two or more windows are order-equivalent (i.e.
5401 * have matching partition and order clauses, even if their names or
5402 * framing clauses differ), then all peer rows must be presented in the
5403 * same order in all of them. If we allowed multiple sort nodes for such
5404 * cases, we'd risk having the peer rows end up in different orders in
5405 * equivalent windows due to sort instability. (See General Rule 4 of
5406 * <window clause> in SQL2008 - SQL2016.)
5407 *
5408 * Additionally, if the entire list of clauses of one window is a prefix
5409 * of another, put first the window with stronger sorting requirements.
5410 * This way we will first sort for stronger window, and won't have to sort
5411 * again for the weaker one.
5412 */
5413 qsort(actives, nActive, sizeof(WindowClauseSortData), common_prefix_cmp);
5414
5415 /* build ordered list of the original WindowClause nodes */
5416 for (int i = 0; i < nActive; i++)
5417 result = lappend(result, actives[i].wc);
5418
5419 pfree(actives);
5420
5421 return result;
5422}
5423
5424/*
5425 * common_prefix_cmp
5426 * QSort comparison function for WindowClauseSortData
5427 *
5428 * Sort the windows by the required sorting clauses. First, compare the sort
5429 * clauses themselves. Second, if one window's clauses are a prefix of another
5430 * one's clauses, put the window with more sort clauses first.
5431 */
5432static int
5433common_prefix_cmp(const void *a, const void *b)
5434{
5435 const WindowClauseSortData *wcsa = a;
5436 const WindowClauseSortData *wcsb = b;
5437 ListCell *item_a;
5438 ListCell *item_b;
5439
5440 forboth(item_a, wcsa->uniqueOrder, item_b, wcsb->uniqueOrder)
5441 {
5442 SortGroupClause *sca = lfirst_node(SortGroupClause, item_a);
5443 SortGroupClause *scb = lfirst_node(SortGroupClause, item_b);
5444
5445 if (sca->tleSortGroupRef > scb->tleSortGroupRef)
5446 return -1;
5447 else if (sca->tleSortGroupRef < scb->tleSortGroupRef)
5448 return 1;
5449 else if (sca->sortop > scb->sortop)
5450 return -1;
5451 else if (sca->sortop < scb->sortop)
5452 return 1;
5453 else if (sca->nulls_first && !scb->nulls_first)
5454 return -1;
5455 else if (!sca->nulls_first && scb->nulls_first)
5456 return 1;
5457 /* no need to compare eqop, since it is fully determined by sortop */
5458 }
5459
5460 if (list_length(wcsa->uniqueOrder) > list_length(wcsb->uniqueOrder))
5461 return -1;
5462 else if (list_length(wcsa->uniqueOrder) < list_length(wcsb->uniqueOrder))
5463 return 1;
5464
5465 return 0;
5466}
5467
5468/*
5469 * make_window_input_target
5470 * Generate appropriate PathTarget for initial input to WindowAgg nodes.
5471 *
5472 * When the query has window functions, this function computes the desired
5473 * target to be computed by the node just below the first WindowAgg.
5474 * This tlist must contain all values needed to evaluate the window functions,
5475 * compute the final target list, and perform any required final sort step.
5476 * If multiple WindowAggs are needed, each intermediate one adds its window
5477 * function results onto this base tlist; only the topmost WindowAgg computes
5478 * the actual desired target list.
5479 *
5480 * This function is much like make_group_input_target, though not quite enough
5481 * like it to share code. As in that function, we flatten most expressions
5482 * into their component variables. But we do not want to flatten window
5483 * PARTITION BY/ORDER BY clauses, since that might result in multiple
5484 * evaluations of them, which would be bad (possibly even resulting in
5485 * inconsistent answers, if they contain volatile functions).
5486 * Also, we must not flatten GROUP BY clauses that were left unflattened by
5487 * make_group_input_target, because we may no longer have access to the
5488 * individual Vars in them.
5489 *
5490 * Another key difference from make_group_input_target is that we don't
5491 * flatten Aggref expressions, since those are to be computed below the
5492 * window functions and just referenced like Vars above that.
5493 *
5494 * 'final_target' is the query's final target list (in PathTarget form)
5495 * 'activeWindows' is the list of active windows previously identified by
5496 * select_active_windows.
5497 *
5498 * The result is the PathTarget to be computed by the plan node immediately
5499 * below the first WindowAgg node.
5500 */
5501static PathTarget *
5502make_window_input_target(PlannerInfo *root,
5503 PathTarget *final_target,
5504 List *activeWindows)
5505{
5506 Query *parse = root->parse;
5507 PathTarget *input_target;
5508 Bitmapset *sgrefs;
5509 List *flattenable_cols;
5510 List *flattenable_vars;
5511 int i;
5512 ListCell *lc;
5513
5514 Assert(parse->hasWindowFuncs);
5515
5516 /*
5517 * Collect the sortgroupref numbers of window PARTITION/ORDER BY clauses
5518 * into a bitmapset for convenient reference below.
5519 */
5520 sgrefs = NULL;
5521 foreach(lc, activeWindows)
5522 {
5523 WindowClause *wc = lfirst_node(WindowClause, lc);
5524 ListCell *lc2;
5525
5526 foreach(lc2, wc->partitionClause)
5527 {
5528 SortGroupClause *sortcl = lfirst_node(SortGroupClause, lc2);
5529
5530 sgrefs = bms_add_member(sgrefs, sortcl->tleSortGroupRef);
5531 }
5532 foreach(lc2, wc->orderClause)
5533 {
5534 SortGroupClause *sortcl = lfirst_node(SortGroupClause, lc2);
5535
5536 sgrefs = bms_add_member(sgrefs, sortcl->tleSortGroupRef);
5537 }
5538 }
5539
5540 /* Add in sortgroupref numbers of GROUP BY clauses, too */
5541 foreach(lc, parse->groupClause)
5542 {
5543 SortGroupClause *grpcl = lfirst_node(SortGroupClause, lc);
5544
5545 sgrefs = bms_add_member(sgrefs, grpcl->tleSortGroupRef);
5546 }
5547
5548 /*
5549 * Construct a target containing all the non-flattenable targetlist items,
5550 * and save aside the others for a moment.
5551 */
5552 input_target = create_empty_pathtarget();
5553 flattenable_cols = NIL;
5554
5555 i = 0;
5556 foreach(lc, final_target->exprs)
5557 {
5558 Expr *expr = (Expr *) lfirst(lc);
5559 Index sgref = get_pathtarget_sortgroupref(final_target, i);
5560
5561 /*
5562 * Don't want to deconstruct window clauses or GROUP BY items. (Note
5563 * that such items can't contain window functions, so it's okay to
5564 * compute them below the WindowAgg nodes.)
5565 */
5566 if (sgref != 0 && bms_is_member(sgref, sgrefs))
5567 {
5568 /*
5569 * Don't want to deconstruct this value, so add it to the input
5570 * target as-is.
5571 */
5572 add_column_to_pathtarget(input_target, expr, sgref);
5573 }
5574 else
5575 {
5576 /*
5577 * Column is to be flattened, so just remember the expression for
5578 * later call to pull_var_clause.
5579 */
5580 flattenable_cols = lappend(flattenable_cols, expr);
5581 }
5582
5583 i++;
5584 }
5585
5586 /*
5587 * Pull out all the Vars and Aggrefs mentioned in flattenable columns, and
5588 * add them to the input target if not already present. (Some might be
5589 * there already because they're used directly as window/group clauses.)
5590 *
5591 * Note: it's essential to use PVC_INCLUDE_AGGREGATES here, so that any
5592 * Aggrefs are placed in the Agg node's tlist and not left to be computed
5593 * at higher levels. On the other hand, we should recurse into
5594 * WindowFuncs to make sure their input expressions are available.
5595 */
5596 flattenable_vars = pull_var_clause((Node *) flattenable_cols,
5597 PVC_INCLUDE_AGGREGATES |
5598 PVC_RECURSE_WINDOWFUNCS |
5599 PVC_INCLUDE_PLACEHOLDERS);
5600 add_new_columns_to_pathtarget(input_target, flattenable_vars);
5601
5602 /* clean up cruft */
5603 list_free(flattenable_vars);
5604 list_free(flattenable_cols);
5605
5606 /* XXX this causes some redundant cost calculation ... */
5607 return set_pathtarget_cost_width(root, input_target);
5608}
5609
5610/*
5611 * make_pathkeys_for_window
5612 * Create a pathkeys list describing the required input ordering
5613 * for the given WindowClause.
5614 *
5615 * The required ordering is first the PARTITION keys, then the ORDER keys.
5616 * In the future we might try to implement windowing using hashing, in which
5617 * case the ordering could be relaxed, but for now we always sort.
5618 */
5619static List *
5620make_pathkeys_for_window(PlannerInfo *root, WindowClause *wc,
5621 List *tlist)
5622{
5623 List *window_pathkeys;
5624 List *window_sortclauses;
5625
5626 /* Throw error if can't sort */
5627 if (!grouping_is_sortable(wc->partitionClause))
5628 ereport(ERROR,
5629 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
5630 errmsg("could not implement window PARTITION BY"),
5631 errdetail("Window partitioning columns must be of sortable datatypes.")));
5632 if (!grouping_is_sortable(wc->orderClause))
5633 ereport(ERROR,
5634 (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
5635 errmsg("could not implement window ORDER BY"),
5636 errdetail("Window ordering columns must be of sortable datatypes.")));
5637
5638 /* Okay, make the combined pathkeys */
5639 window_sortclauses = list_concat(list_copy(wc->partitionClause),
5640 list_copy(wc->orderClause));
5641 window_pathkeys = make_pathkeys_for_sortclauses(root,
5642 window_sortclauses,
5643 tlist);
5644 list_free(window_sortclauses);
5645 return window_pathkeys;
5646}
5647
5648/*
5649 * make_sort_input_target
5650 * Generate appropriate PathTarget for initial input to Sort step.
5651 *
5652 * If the query has ORDER BY, this function chooses the target to be computed
5653 * by the node just below the Sort (and DISTINCT, if any, since Unique can't
5654 * project) steps. This might or might not be identical to the query's final
5655 * output target.
5656 *
5657 * The main argument for keeping the sort-input tlist the same as the final
5658 * is that we avoid a separate projection node (which will be needed if
5659 * they're different, because Sort can't project). However, there are also
5660 * advantages to postponing tlist evaluation till after the Sort: it ensures
5661 * a consistent order of evaluation for any volatile functions in the tlist,
5662 * and if there's also a LIMIT, we can stop the query without ever computing
5663 * tlist functions for later rows, which is beneficial for both volatile and
5664 * expensive functions.
5665 *
5666 * Our current policy is to postpone volatile expressions till after the sort
5667 * unconditionally (assuming that that's possible, ie they are in plain tlist
5668 * columns and not ORDER BY/GROUP BY/DISTINCT columns). We also prefer to
5669 * postpone set-returning expressions, because running them beforehand would
5670 * bloat the sort dataset, and because it might cause unexpected output order
5671 * if the sort isn't stable. However there's a constraint on that: all SRFs
5672 * in the tlist should be evaluated at the same plan step, so that they can
5673 * run in sync in nodeProjectSet. So if any SRFs are in sort columns, we
5674 * mustn't postpone any SRFs. (Note that in principle that policy should
5675 * probably get applied to the group/window input targetlists too, but we
5676 * have not done that historically.) Lastly, expensive expressions are
5677 * postponed if there is a LIMIT, or if root->tuple_fraction shows that
5678 * partial evaluation of the query is possible (if neither is true, we expect
5679 * to have to evaluate the expressions for every row anyway), or if there are
5680 * any volatile or set-returning expressions (since once we've put in a
5681 * projection at all, it won't cost any more to postpone more stuff).
5682 *
5683 * Another issue that could potentially be considered here is that
5684 * evaluating tlist expressions could result in data that's either wider
5685 * or narrower than the input Vars, thus changing the volume of data that
5686 * has to go through the Sort. However, we usually have only a very bad
5687 * idea of the output width of any expression more complex than a Var,
5688 * so for now it seems too risky to try to optimize on that basis.
5689 *
5690 * Note that if we do produce a modified sort-input target, and then the
5691 * query ends up not using an explicit Sort, no particular harm is done:
5692 * we'll initially use the modified target for the preceding path nodes,
5693 * but then change them to the final target with apply_projection_to_path.
5694 * Moreover, in such a case the guarantees about evaluation order of
5695 * volatile functions still hold, since the rows are sorted already.
5696 *
5697 * This function has some things in common with make_group_input_target and
5698 * make_window_input_target, though the detailed rules for what to do are
5699 * different. We never flatten/postpone any grouping or ordering columns;
5700 * those are needed before the sort. If we do flatten a particular
5701 * expression, we leave Aggref and WindowFunc nodes alone, since those were
5702 * computed earlier.
5703 *
5704 * 'final_target' is the query's final target list (in PathTarget form)
5705 * 'have_postponed_srfs' is an output argument, see below
5706 *
5707 * The result is the PathTarget to be computed by the plan node immediately
5708 * below the Sort step (and the Distinct step, if any). This will be
5709 * exactly final_target if we decide a projection step wouldn't be helpful.
5710 *
5711 * In addition, *have_postponed_srfs is set to true if we choose to postpone
5712 * any set-returning functions to after the Sort.
5713 */
5714static PathTarget *
5715make_sort_input_target(PlannerInfo *root,
5716 PathTarget *final_target,
5717 bool *have_postponed_srfs)
5718{
5719 Query *parse = root->parse;
5720 PathTarget *input_target;
5721 int ncols;
5722 bool *col_is_srf;
5723 bool *postpone_col;
5724 bool have_srf;
5725 bool have_volatile;
5726 bool have_expensive;
5727 bool have_srf_sortcols;
5728 bool postpone_srfs;
5729 List *postponable_cols;
5730 List *postponable_vars;
5731 int i;
5732 ListCell *lc;
5733
5734 /* Shouldn't get here unless query has ORDER BY */
5735 Assert(parse->sortClause);
5736
5737 *have_postponed_srfs = false; /* default result */
5738
5739 /* Inspect tlist and collect per-column information */
5740 ncols = list_length(final_target->exprs);
5741 col_is_srf = (bool *) palloc0(ncols * sizeof(bool));
5742 postpone_col = (bool *) palloc0(ncols * sizeof(bool));
5743 have_srf = have_volatile = have_expensive = have_srf_sortcols = false;
5744
5745 i = 0;
5746 foreach(lc, final_target->exprs)
5747 {
5748 Expr *expr = (Expr *) lfirst(lc);
5749
5750 /*
5751 * If the column has a sortgroupref, assume it has to be evaluated
5752 * before sorting. Generally such columns would be ORDER BY, GROUP
5753 * BY, etc targets. One exception is columns that were removed from
5754 * GROUP BY by remove_useless_groupby_columns() ... but those would
5755 * only be Vars anyway. There don't seem to be any cases where it
5756 * would be worth the trouble to double-check.
5757 */
5758 if (get_pathtarget_sortgroupref(final_target, i) == 0)
5759 {
5760 /*
5761 * Check for SRF or volatile functions. Check the SRF case first
5762 * because we must know whether we have any postponed SRFs.
5763 */
5764 if (parse->hasTargetSRFs &&
5765 expression_returns_set((Node *) expr))
5766 {
5767 /* We'll decide below whether these are postponable */
5768 col_is_srf[i] = true;
5769 have_srf = true;
5770 }
5771 else if (contain_volatile_functions((Node *) expr))
5772 {
5773 /* Unconditionally postpone */
5774 postpone_col[i] = true;
5775 have_volatile = true;
5776 }
5777 else
5778 {
5779 /*
5780 * Else check the cost. XXX it's annoying to have to do this
5781 * when set_pathtarget_cost_width() just did it. Refactor to
5782 * allow sharing the work?
5783 */
5784 QualCost cost;
5785
5786 cost_qual_eval_node(&cost, (Node *) expr, root);
5787
5788 /*
5789 * We arbitrarily define "expensive" as "more than 10X
5790 * cpu_operator_cost". Note this will take in any PL function
5791 * with default cost.
5792 */
5793 if (cost.per_tuple > 10 * cpu_operator_cost)
5794 {
5795 postpone_col[i] = true;
5796 have_expensive = true;
5797 }
5798 }
5799 }
5800 else
5801 {
5802 /* For sortgroupref cols, just check if any contain SRFs */
5803 if (!have_srf_sortcols &&
5804 parse->hasTargetSRFs &&
5805 expression_returns_set((Node *) expr))
5806 have_srf_sortcols = true;
5807 }
5808
5809 i++;
5810 }
5811
5812 /*
5813 * We can postpone SRFs if we have some but none are in sortgroupref cols.
5814 */
5815 postpone_srfs = (have_srf && !have_srf_sortcols);
5816
5817 /*
5818 * If we don't need a post-sort projection, just return final_target.
5819 */
5820 if (!(postpone_srfs || have_volatile ||
5821 (have_expensive &&
5822 (parse->limitCount || root->tuple_fraction > 0))))
5823 return final_target;
5824
5825 /*
5826 * Report whether the post-sort projection will contain set-returning
5827 * functions. This is important because it affects whether the Sort can
5828 * rely on the query's LIMIT (if any) to bound the number of rows it needs
5829 * to return.
5830 */
5831 *have_postponed_srfs = postpone_srfs;
5832
5833 /*
5834 * Construct the sort-input target, taking all non-postponable columns and
5835 * then adding Vars, PlaceHolderVars, Aggrefs, and WindowFuncs found in
5836 * the postponable ones.
5837 */
5838 input_target = create_empty_pathtarget();
5839 postponable_cols = NIL;
5840
5841 i = 0;
5842 foreach(lc, final_target->exprs)
5843 {
5844 Expr *expr = (Expr *) lfirst(lc);
5845
5846 if (postpone_col[i] || (postpone_srfs && col_is_srf[i]))
5847 postponable_cols = lappend(postponable_cols, expr);
5848 else
5849 add_column_to_pathtarget(input_target, expr,
5850 get_pathtarget_sortgroupref(final_target, i));
5851
5852 i++;
5853 }
5854
5855 /*
5856 * Pull out all the Vars, Aggrefs, and WindowFuncs mentioned in
5857 * postponable columns, and add them to the sort-input target if not
5858 * already present. (Some might be there already.) We mustn't
5859 * deconstruct Aggrefs or WindowFuncs here, since the projection node
5860 * would be unable to recompute them.
5861 */
5862 postponable_vars = pull_var_clause((Node *) postponable_cols,
5863 PVC_INCLUDE_AGGREGATES |
5864 PVC_INCLUDE_WINDOWFUNCS |
5865 PVC_INCLUDE_PLACEHOLDERS);
5866 add_new_columns_to_pathtarget(input_target, postponable_vars);
5867
5868 /* clean up cruft */
5869 list_free(postponable_vars);
5870 list_free(postponable_cols);
5871
5872 /* XXX this represents even more redundant cost calculation ... */
5873 return set_pathtarget_cost_width(root, input_target);
5874}
5875
5876/*
5877 * get_cheapest_fractional_path
5878 * Find the cheapest path for retrieving a specified fraction of all
5879 * the tuples expected to be returned by the given relation.
5880 *
5881 * We interpret tuple_fraction the same way as grouping_planner.
5882 *
5883 * We assume set_cheapest() has been run on the given rel.
5884 */
5885Path *
5886get_cheapest_fractional_path(RelOptInfo *rel, double tuple_fraction)
5887{
5888 Path *best_path = rel->cheapest_total_path;
5889 ListCell *l;
5890
5891 /* If all tuples will be retrieved, just return the cheapest-total path */
5892 if (tuple_fraction <= 0.0)
5893 return best_path;
5894
5895 /* Convert absolute # of tuples to a fraction; no need to clamp to 0..1 */
5896 if (tuple_fraction >= 1.0 && best_path->rows > 0)
5897 tuple_fraction /= best_path->rows;
5898
5899 foreach(l, rel->pathlist)
5900 {
5901 Path *path = (Path *) lfirst(l);
5902
5903 if (path == rel->cheapest_total_path ||
5904 compare_fractional_path_costs(best_path, path, tuple_fraction) <= 0)
5905 continue;
5906
5907 best_path = path;
5908 }
5909
5910 return best_path;
5911}
5912
5913/*
5914 * adjust_paths_for_srfs
5915 * Fix up the Paths of the given upperrel to handle tSRFs properly.
5916 *
5917 * The executor can only handle set-returning functions that appear at the
5918 * top level of the targetlist of a ProjectSet plan node. If we have any SRFs
5919 * that are not at top level, we need to split up the evaluation into multiple
5920 * plan levels in which each level satisfies this constraint. This function
5921 * modifies each Path of an upperrel that (might) compute any SRFs in its
5922 * output tlist to insert appropriate projection steps.
5923 *
5924 * The given targets and targets_contain_srfs lists are from
5925 * split_pathtarget_at_srfs(). We assume the existing Paths emit the first
5926 * target in targets.
5927 */
5928static void
5929adjust_paths_for_srfs(PlannerInfo *root, RelOptInfo *rel,
5930 List *targets, List *targets_contain_srfs)
5931{
5932 ListCell *lc;
5933
5934 Assert(list_length(targets) == list_length(targets_contain_srfs));
5935 Assert(!linitial_int(targets_contain_srfs));
5936
5937 /* If no SRFs appear at this plan level, nothing to do */
5938 if (list_length(targets) == 1)
5939 return;
5940
5941 /*
5942 * Stack SRF-evaluation nodes atop each path for the rel.
5943 *
5944 * In principle we should re-run set_cheapest() here to identify the
5945 * cheapest path, but it seems unlikely that adding the same tlist eval
5946 * costs to all the paths would change that, so we don't bother. Instead,
5947 * just assume that the cheapest-startup and cheapest-total paths remain
5948 * so. (There should be no parameterized paths anymore, so we needn't
5949 * worry about updating cheapest_parameterized_paths.)
5950 */
5951 foreach(lc, rel->pathlist)
5952 {
5953 Path *subpath = (Path *) lfirst(lc);
5954 Path *newpath = subpath;
5955 ListCell *lc1,
5956 *lc2;
5957
5958 Assert(subpath->param_info == NULL);
5959 forboth(lc1, targets, lc2, targets_contain_srfs)
5960 {
5961 PathTarget *thistarget = lfirst_node(PathTarget, lc1);
5962 bool contains_srfs = (bool) lfirst_int(lc2);
5963
5964 /* If this level doesn't contain SRFs, do regular projection */
5965 if (contains_srfs)
5966 newpath = (Path *) create_set_projection_path(root,
5967 rel,
5968 newpath,
5969 thistarget);
5970 else
5971 newpath = (Path *) apply_projection_to_path(root,
5972 rel,
5973 newpath,
5974 thistarget);
5975 }
5976 lfirst(lc) = newpath;
5977 if (subpath == rel->cheapest_startup_path)
5978 rel->cheapest_startup_path = newpath;
5979 if (subpath == rel->cheapest_total_path)
5980 rel->cheapest_total_path = newpath;
5981 }
5982
5983 /* Likewise for partial paths, if any */
5984 foreach(lc, rel->partial_pathlist)
5985 {
5986 Path *subpath = (Path *) lfirst(lc);
5987 Path *newpath = subpath;
5988 ListCell *lc1,
5989 *lc2;
5990
5991 Assert(subpath->param_info == NULL);
5992 forboth(lc1, targets, lc2, targets_contain_srfs)
5993 {
5994 PathTarget *thistarget = lfirst_node(PathTarget, lc1);
5995 bool contains_srfs = (bool) lfirst_int(lc2);
5996
5997 /* If this level doesn't contain SRFs, do regular projection */
5998 if (contains_srfs)
5999 newpath = (Path *) create_set_projection_path(root,
6000 rel,
6001 newpath,
6002 thistarget);
6003 else
6004 {
6005 /* avoid apply_projection_to_path, in case of multiple refs */
6006 newpath = (Path *) create_projection_path(root,
6007 rel,
6008 newpath,
6009 thistarget);
6010 }
6011 }
6012 lfirst(lc) = newpath;
6013 }
6014}
6015
6016/*
6017 * expression_planner
6018 * Perform planner's transformations on a standalone expression.
6019 *
6020 * Various utility commands need to evaluate expressions that are not part
6021 * of a plannable query. They can do so using the executor's regular
6022 * expression-execution machinery, but first the expression has to be fed
6023 * through here to transform it from parser output to something executable.
6024 *
6025 * Currently, we disallow sublinks in standalone expressions, so there's no
6026 * real "planning" involved here. (That might not always be true though.)
6027 * What we must do is run eval_const_expressions to ensure that any function
6028 * calls are converted to positional notation and function default arguments
6029 * get inserted. The fact that constant subexpressions get simplified is a
6030 * side-effect that is useful when the expression will get evaluated more than
6031 * once. Also, we must fix operator function IDs.
6032 *
6033 * This does not return any information about dependencies of the expression.
6034 * Hence callers should use the results only for the duration of the current
6035 * query. Callers that would like to cache the results for longer should use
6036 * expression_planner_with_deps, probably via the plancache.
6037 *
6038 * Note: this must not make any damaging changes to the passed-in expression
6039 * tree. (It would actually be okay to apply fix_opfuncids to it, but since
6040 * we first do an expression_tree_mutator-based walk, what is returned will
6041 * be a new node tree.) The result is constructed in the current memory
6042 * context; beware that this can leak a lot of additional stuff there, too.
6043 */
6044Expr *
6045expression_planner(Expr *expr)
6046{
6047 Node *result;
6048
6049 /*
6050 * Convert named-argument function calls, insert default arguments and
6051 * simplify constant subexprs
6052 */
6053 result = eval_const_expressions(NULL, (Node *) expr);
6054
6055 /* Fill in opfuncid values if missing */
6056 fix_opfuncids(result);
6057
6058 return (Expr *) result;
6059}
6060
6061/*
6062 * expression_planner_with_deps
6063 * Perform planner's transformations on a standalone expression,
6064 * returning expression dependency information along with the result.
6065 *
6066 * This is identical to expression_planner() except that it also returns
6067 * information about possible dependencies of the expression, ie identities of
6068 * objects whose definitions affect the result. As in a PlannedStmt, these
6069 * are expressed as a list of relation Oids and a list of PlanInvalItems.
6070 */
6071Expr *
6072expression_planner_with_deps(Expr *expr,
6073 List **relationOids,
6074 List **invalItems)
6075{
6076 Node *result;
6077 PlannerGlobal glob;
6078 PlannerInfo root;
6079
6080 /* Make up dummy planner state so we can use setrefs machinery */
6081 MemSet(&glob, 0, sizeof(glob));
6082 glob.type = T_PlannerGlobal;
6083 glob.relationOids = NIL;
6084 glob.invalItems = NIL;
6085
6086 MemSet(&root, 0, sizeof(root));
6087 root.type = T_PlannerInfo;
6088 root.glob = &glob;
6089
6090 /*
6091 * Convert named-argument function calls, insert default arguments and
6092 * simplify constant subexprs. Collect identities of inlined functions
6093 * and elided domains, too.
6094 */
6095 result = eval_const_expressions(&root, (Node *) expr);
6096
6097 /* Fill in opfuncid values if missing */
6098 fix_opfuncids(result);
6099
6100 /*
6101 * Now walk the finished expression to find anything else we ought to
6102 * record as an expression dependency.
6103 */
6104 (void) extract_query_dependencies_walker(result, &root);
6105
6106 *relationOids = glob.relationOids;
6107 *invalItems = glob.invalItems;
6108
6109 return (Expr *) result;
6110}
6111
6112
6113/*
6114 * plan_cluster_use_sort
6115 * Use the planner to decide how CLUSTER should implement sorting
6116 *
6117 * tableOid is the OID of a table to be clustered on its index indexOid
6118 * (which is already known to be a btree index). Decide whether it's
6119 * cheaper to do an indexscan or a seqscan-plus-sort to execute the CLUSTER.
6120 * Return true to use sorting, false to use an indexscan.
6121 *
6122 * Note: caller had better already hold some type of lock on the table.
6123 */
6124bool
6125plan_cluster_use_sort(Oid tableOid, Oid indexOid)
6126{
6127 PlannerInfo *root;
6128 Query *query;
6129 PlannerGlobal *glob;
6130 RangeTblEntry *rte;
6131 RelOptInfo *rel;
6132 IndexOptInfo *indexInfo;
6133 QualCost indexExprCost;
6134 Cost comparisonCost;
6135 Path *seqScanPath;
6136 Path seqScanAndSortPath;
6137 IndexPath *indexScanPath;
6138 ListCell *lc;
6139
6140 /* We can short-circuit the cost comparison if indexscans are disabled */
6141 if (!enable_indexscan)
6142 return true; /* use sort */
6143
6144 /* Set up mostly-dummy planner state */
6145 query = makeNode(Query);
6146 query->commandType = CMD_SELECT;
6147
6148 glob = makeNode(PlannerGlobal);
6149
6150 root = makeNode(PlannerInfo);
6151 root->parse = query;
6152 root->glob = glob;
6153 root->query_level = 1;
6154 root->planner_cxt = CurrentMemoryContext;
6155 root->wt_param_id = -1;
6156
6157 /* Build a minimal RTE for the rel */
6158 rte = makeNode(RangeTblEntry);
6159 rte->rtekind = RTE_RELATION;
6160 rte->relid = tableOid;
6161 rte->relkind = RELKIND_RELATION; /* Don't be too picky. */
6162 rte->rellockmode = AccessShareLock;
6163 rte->lateral = false;
6164 rte->inh = false;
6165 rte->inFromCl = true;
6166 query->rtable = list_make1(rte);
6167
6168 /* Set up RTE/RelOptInfo arrays */
6169 setup_simple_rel_arrays(root);
6170
6171 /* Build RelOptInfo */
6172 rel = build_simple_rel(root, 1, NULL);
6173
6174 /* Locate IndexOptInfo for the target index */
6175 indexInfo = NULL;
6176 foreach(lc, rel->indexlist)
6177 {
6178 indexInfo = lfirst_node(IndexOptInfo, lc);
6179 if (indexInfo->indexoid == indexOid)
6180 break;
6181 }
6182
6183 /*
6184 * It's possible that get_relation_info did not generate an IndexOptInfo
6185 * for the desired index; this could happen if it's not yet reached its
6186 * indcheckxmin usability horizon, or if it's a system index and we're
6187 * ignoring system indexes. In such cases we should tell CLUSTER to not
6188 * trust the index contents but use seqscan-and-sort.
6189 */
6190 if (lc == NULL) /* not in the list? */
6191 return true; /* use sort */
6192
6193 /*
6194 * Rather than doing all the pushups that would be needed to use
6195 * set_baserel_size_estimates, just do a quick hack for rows and width.
6196 */
6197 rel->rows = rel->tuples;
6198 rel->reltarget->width = get_relation_data_width(tableOid, NULL);
6199
6200 root->total_table_pages = rel->pages;
6201
6202 /*
6203 * Determine eval cost of the index expressions, if any. We need to
6204 * charge twice that amount for each tuple comparison that happens during
6205 * the sort, since tuplesort.c will have to re-evaluate the index
6206 * expressions each time. (XXX that's pretty inefficient...)
6207 */
6208 cost_qual_eval(&indexExprCost, indexInfo->indexprs, root);
6209 comparisonCost = 2.0 * (indexExprCost.startup + indexExprCost.per_tuple);
6210
6211 /* Estimate the cost of seq scan + sort */
6212 seqScanPath = create_seqscan_path(root, rel, NULL, 0);
6213 cost_sort(&seqScanAndSortPath, root, NIL,
6214 seqScanPath->total_cost, rel->tuples, rel->reltarget->width,
6215 comparisonCost, maintenance_work_mem, -1.0);
6216
6217 /* Estimate the cost of index scan */
6218 indexScanPath = create_index_path(root, indexInfo,
6219 NIL, NIL, NIL, NIL,
6220 ForwardScanDirection, false,
6221 NULL, 1.0, false);
6222
6223 return (seqScanAndSortPath.total_cost < indexScanPath->path.total_cost);
6224}
6225
6226/*
6227 * plan_create_index_workers
6228 * Use the planner to decide how many parallel worker processes
6229 * CREATE INDEX should request for use
6230 *
6231 * tableOid is the table on which the index is to be built. indexOid is the
6232 * OID of an index to be created or reindexed (which must be a btree index).
6233 *
6234 * Return value is the number of parallel worker processes to request. It
6235 * may be unsafe to proceed if this is 0. Note that this does not include the
6236 * leader participating as a worker (value is always a number of parallel
6237 * worker processes).
6238 *
6239 * Note: caller had better already hold some type of lock on the table and
6240 * index.
6241 */
6242int
6243plan_create_index_workers(Oid tableOid, Oid indexOid)
6244{
6245 PlannerInfo *root;
6246 Query *query;
6247 PlannerGlobal *glob;
6248 RangeTblEntry *rte;
6249 Relation heap;
6250 Relation index;
6251 RelOptInfo *rel;
6252 int parallel_workers;
6253 BlockNumber heap_blocks;
6254 double reltuples;
6255 double allvisfrac;
6256
6257 /* Return immediately when parallelism disabled */
6258 if (max_parallel_maintenance_workers == 0)
6259 return 0;
6260
6261 /* Set up largely-dummy planner state */
6262 query = makeNode(Query);
6263 query->commandType = CMD_SELECT;
6264
6265 glob = makeNode(PlannerGlobal);
6266
6267 root = makeNode(PlannerInfo);
6268 root->parse = query;
6269 root->glob = glob;
6270 root->query_level = 1;
6271 root->planner_cxt = CurrentMemoryContext;
6272 root->wt_param_id = -1;
6273
6274 /*
6275 * Build a minimal RTE.
6276 *
6277 * Mark the RTE with inh = true. This is a kludge to prevent
6278 * get_relation_info() from fetching index info, which is necessary
6279 * because it does not expect that any IndexOptInfo is currently
6280 * undergoing REINDEX.
6281 */
6282 rte = makeNode(RangeTblEntry);
6283 rte->rtekind = RTE_RELATION;
6284 rte->relid = tableOid;
6285 rte->relkind = RELKIND_RELATION; /* Don't be too picky. */
6286 rte->rellockmode = AccessShareLock;
6287 rte->lateral = false;
6288 rte->inh = true;
6289 rte->inFromCl = true;
6290 query->rtable = list_make1(rte);
6291
6292 /* Set up RTE/RelOptInfo arrays */
6293 setup_simple_rel_arrays(root);
6294
6295 /* Build RelOptInfo */
6296 rel = build_simple_rel(root, 1, NULL);
6297
6298 /* Rels are assumed already locked by the caller */
6299 heap = table_open(tableOid, NoLock);
6300 index = index_open(indexOid, NoLock);
6301
6302 /*
6303 * Determine if it's safe to proceed.
6304 *
6305 * Currently, parallel workers can't access the leader's temporary tables.
6306 * Furthermore, any index predicate or index expressions must be parallel
6307 * safe.
6308 */
6309 if (heap->rd_rel->relpersistence == RELPERSISTENCE_TEMP ||
6310 !is_parallel_safe(root, (Node *) RelationGetIndexExpressions(index)) ||
6311 !is_parallel_safe(root, (Node *) RelationGetIndexPredicate(index)))
6312 {
6313 parallel_workers = 0;
6314 goto done;
6315 }
6316
6317 /*
6318 * If parallel_workers storage parameter is set for the table, accept that
6319 * as the number of parallel worker processes to launch (though still cap
6320 * at max_parallel_maintenance_workers). Note that we deliberately do not
6321 * consider any other factor when parallel_workers is set. (e.g., memory
6322 * use by workers.)
6323 */
6324 if (rel->rel_parallel_workers != -1)
6325 {
6326 parallel_workers = Min(rel->rel_parallel_workers,
6327 max_parallel_maintenance_workers);
6328 goto done;
6329 }
6330
6331 /*
6332 * Estimate heap relation size ourselves, since rel->pages cannot be
6333 * trusted (heap RTE was marked as inheritance parent)
6334 */
6335 estimate_rel_size(heap, NULL, &heap_blocks, &reltuples, &allvisfrac);
6336
6337 /*
6338 * Determine number of workers to scan the heap relation using generic
6339 * model
6340 */
6341 parallel_workers = compute_parallel_worker(rel, heap_blocks, -1,
6342 max_parallel_maintenance_workers);
6343
6344 /*
6345 * Cap workers based on available maintenance_work_mem as needed.
6346 *
6347 * Note that each tuplesort participant receives an even share of the
6348 * total maintenance_work_mem budget. Aim to leave participants
6349 * (including the leader as a participant) with no less than 32MB of
6350 * memory. This leaves cases where maintenance_work_mem is set to 64MB
6351 * immediately past the threshold of being capable of launching a single
6352 * parallel worker to sort.
6353 */
6354 while (parallel_workers > 0 &&
6355 maintenance_work_mem / (parallel_workers + 1) < 32768L)
6356 parallel_workers--;
6357
6358done:
6359 index_close(index, NoLock);
6360 table_close(heap, NoLock);
6361
6362 return parallel_workers;
6363}
6364
6365/*
6366 * add_paths_to_grouping_rel
6367 *
6368 * Add non-partial paths to grouping relation.
6369 */
6370static void
6371add_paths_to_grouping_rel(PlannerInfo *root, RelOptInfo *input_rel,
6372 RelOptInfo *grouped_rel,
6373 RelOptInfo *partially_grouped_rel,
6374 const AggClauseCosts *agg_costs,
6375 grouping_sets_data *gd, double dNumGroups,
6376 GroupPathExtraData *extra)
6377{
6378 Query *parse = root->parse;
6379 Path *cheapest_path = input_rel->cheapest_total_path;
6380 ListCell *lc;
6381 bool can_hash = (extra->flags & GROUPING_CAN_USE_HASH) != 0;
6382 bool can_sort = (extra->flags & GROUPING_CAN_USE_SORT) != 0;
6383 List *havingQual = (List *) extra->havingQual;
6384 AggClauseCosts *agg_final_costs = &extra->agg_final_costs;
6385
6386 if (can_sort)
6387 {
6388 /*
6389 * Use any available suitably-sorted path as input, and also consider
6390 * sorting the cheapest-total path.
6391 */
6392 foreach(lc, input_rel->pathlist)
6393 {
6394 Path *path = (Path *) lfirst(lc);
6395 bool is_sorted;
6396
6397 is_sorted = pathkeys_contained_in(root->group_pathkeys,
6398 path->pathkeys);
6399 if (path == cheapest_path || is_sorted)
6400 {
6401 /* Sort the cheapest-total path if it isn't already sorted */
6402 if (!is_sorted)
6403 path = (Path *) create_sort_path(root,
6404 grouped_rel,
6405 path,
6406 root->group_pathkeys,
6407 -1.0);
6408
6409 /* Now decide what to stick atop it */
6410 if (parse->groupingSets)
6411 {
6412 consider_groupingsets_paths(root, grouped_rel,
6413 path, true, can_hash,
6414 gd, agg_costs, dNumGroups);
6415 }
6416 else if (parse->hasAggs)
6417 {
6418 /*
6419 * We have aggregation, possibly with plain GROUP BY. Make
6420 * an AggPath.
6421 */
6422 add_path(grouped_rel, (Path *)
6423 create_agg_path(root,
6424 grouped_rel,
6425 path,
6426 grouped_rel->reltarget,
6427 parse->groupClause ? AGG_SORTED : AGG_PLAIN,
6428 AGGSPLIT_SIMPLE,
6429 parse->groupClause,
6430 havingQual,
6431 agg_costs,
6432 dNumGroups));
6433 }
6434 else if (parse->groupClause)
6435 {
6436 /*
6437 * We have GROUP BY without aggregation or grouping sets.
6438 * Make a GroupPath.
6439 */
6440 add_path(grouped_rel, (Path *)
6441 create_group_path(root,
6442 grouped_rel,
6443 path,
6444 parse->groupClause,
6445 havingQual,
6446 dNumGroups));
6447 }
6448 else
6449 {
6450 /* Other cases should have been handled above */
6451 Assert(false);
6452 }
6453 }
6454 }
6455
6456 /*
6457 * Instead of operating directly on the input relation, we can
6458 * consider finalizing a partially aggregated path.
6459 */
6460 if (partially_grouped_rel != NULL)
6461 {
6462 foreach(lc, partially_grouped_rel->pathlist)
6463 {
6464 Path *path = (Path *) lfirst(lc);
6465
6466 /*
6467 * Insert a Sort node, if required. But there's no point in
6468 * sorting anything but the cheapest path.
6469 */
6470 if (!pathkeys_contained_in(root->group_pathkeys, path->pathkeys))
6471 {
6472 if (path != partially_grouped_rel->cheapest_total_path)
6473 continue;
6474 path = (Path *) create_sort_path(root,
6475 grouped_rel,
6476 path,
6477 root->group_pathkeys,
6478 -1.0);
6479 }
6480
6481 if (parse->hasAggs)
6482 add_path(grouped_rel, (Path *)
6483 create_agg_path(root,
6484 grouped_rel,
6485 path,
6486 grouped_rel->reltarget,
6487 parse->groupClause ? AGG_SORTED : AGG_PLAIN,
6488 AGGSPLIT_FINAL_DESERIAL,
6489 parse->groupClause,
6490 havingQual,
6491 agg_final_costs,
6492 dNumGroups));
6493 else
6494 add_path(grouped_rel, (Path *)
6495 create_group_path(root,
6496 grouped_rel,
6497 path,
6498 parse->groupClause,
6499 havingQual,
6500 dNumGroups));
6501 }
6502 }
6503 }
6504
6505 if (can_hash)
6506 {
6507 double hashaggtablesize;
6508
6509 if (parse->groupingSets)
6510 {
6511 /*
6512 * Try for a hash-only groupingsets path over unsorted input.
6513 */
6514 consider_groupingsets_paths(root, grouped_rel,
6515 cheapest_path, false, true,
6516 gd, agg_costs, dNumGroups);
6517 }
6518 else
6519 {
6520 hashaggtablesize = estimate_hashagg_tablesize(cheapest_path,
6521 agg_costs,
6522 dNumGroups);
6523
6524 /*
6525 * Provided that the estimated size of the hashtable does not
6526 * exceed work_mem, we'll generate a HashAgg Path, although if we
6527 * were unable to sort above, then we'd better generate a Path, so
6528 * that we at least have one.
6529 */
6530 if (hashaggtablesize < work_mem * 1024L ||
6531 grouped_rel->pathlist == NIL)
6532 {
6533 /*
6534 * We just need an Agg over the cheapest-total input path,
6535 * since input order won't matter.
6536 */
6537 add_path(grouped_rel, (Path *)
6538 create_agg_path(root, grouped_rel,
6539 cheapest_path,
6540 grouped_rel->reltarget,
6541 AGG_HASHED,
6542 AGGSPLIT_SIMPLE,
6543 parse->groupClause,
6544 havingQual,
6545 agg_costs,
6546 dNumGroups));
6547 }
6548 }
6549
6550 /*
6551 * Generate a Finalize HashAgg Path atop of the cheapest partially
6552 * grouped path, assuming there is one. Once again, we'll only do this
6553 * if it looks as though the hash table won't exceed work_mem.
6554 */
6555 if (partially_grouped_rel && partially_grouped_rel->pathlist)
6556 {
6557 Path *path = partially_grouped_rel->cheapest_total_path;
6558
6559 hashaggtablesize = estimate_hashagg_tablesize(path,
6560 agg_final_costs,
6561 dNumGroups);
6562
6563 if (hashaggtablesize < work_mem * 1024L)
6564 add_path(grouped_rel, (Path *)
6565 create_agg_path(root,
6566 grouped_rel,
6567 path,
6568 grouped_rel->reltarget,
6569 AGG_HASHED,
6570 AGGSPLIT_FINAL_DESERIAL,
6571 parse->groupClause,
6572 havingQual,
6573 agg_final_costs,
6574 dNumGroups));
6575 }
6576 }
6577
6578 /*
6579 * When partitionwise aggregate is used, we might have fully aggregated
6580 * paths in the partial pathlist, because add_paths_to_append_rel() will
6581 * consider a path for grouped_rel consisting of a Parallel Append of
6582 * non-partial paths from each child.
6583 */
6584 if (grouped_rel->partial_pathlist != NIL)
6585 gather_grouping_paths(root, grouped_rel);
6586}
6587
6588/*
6589 * create_partial_grouping_paths
6590 *
6591 * Create a new upper relation representing the result of partial aggregation
6592 * and populate it with appropriate paths. Note that we don't finalize the
6593 * lists of paths here, so the caller can add additional partial or non-partial
6594 * paths and must afterward call gather_grouping_paths and set_cheapest on
6595 * the returned upper relation.
6596 *
6597 * All paths for this new upper relation -- both partial and non-partial --
6598 * have been partially aggregated but require a subsequent FinalizeAggregate
6599 * step.
6600 *
6601 * NB: This function is allowed to return NULL if it determines that there is
6602 * no real need to create a new RelOptInfo.
6603 */
6604static RelOptInfo *
6605create_partial_grouping_paths(PlannerInfo *root,
6606 RelOptInfo *grouped_rel,
6607 RelOptInfo *input_rel,
6608 grouping_sets_data *gd,
6609 GroupPathExtraData *extra,
6610 bool force_rel_creation)
6611{
6612 Query *parse = root->parse;
6613 RelOptInfo *partially_grouped_rel;
6614 AggClauseCosts *agg_partial_costs = &extra->agg_partial_costs;
6615 AggClauseCosts *agg_final_costs = &extra->agg_final_costs;
6616 Path *cheapest_partial_path = NULL;
6617 Path *cheapest_total_path = NULL;
6618 double dNumPartialGroups = 0;
6619 double dNumPartialPartialGroups = 0;
6620 ListCell *lc;
6621 bool can_hash = (extra->flags & GROUPING_CAN_USE_HASH) != 0;
6622 bool can_sort = (extra->flags & GROUPING_CAN_USE_SORT) != 0;
6623
6624 /*
6625 * Consider whether we should generate partially aggregated non-partial
6626 * paths. We can only do this if we have a non-partial path, and only if
6627 * the parent of the input rel is performing partial partitionwise
6628 * aggregation. (Note that extra->patype is the type of partitionwise
6629 * aggregation being used at the parent level, not this level.)
6630 */
6631 if (input_rel->pathlist != NIL &&
6632 extra->patype == PARTITIONWISE_AGGREGATE_PARTIAL)
6633 cheapest_total_path = input_rel->cheapest_total_path;
6634
6635 /*
6636 * If parallelism is possible for grouped_rel, then we should consider
6637 * generating partially-grouped partial paths. However, if the input rel
6638 * has no partial paths, then we can't.
6639 */
6640 if (grouped_rel->consider_parallel && input_rel->partial_pathlist != NIL)
6641 cheapest_partial_path = linitial(input_rel->partial_pathlist);
6642
6643 /*
6644 * If we can't partially aggregate partial paths, and we can't partially
6645 * aggregate non-partial paths, then don't bother creating the new
6646 * RelOptInfo at all, unless the caller specified force_rel_creation.
6647 */
6648 if (cheapest_total_path == NULL &&
6649 cheapest_partial_path == NULL &&
6650 !force_rel_creation)
6651 return NULL;
6652
6653 /*
6654 * Build a new upper relation to represent the result of partially
6655 * aggregating the rows from the input relation.
6656 */
6657 partially_grouped_rel = fetch_upper_rel(root,
6658 UPPERREL_PARTIAL_GROUP_AGG,
6659 grouped_rel->relids);
6660 partially_grouped_rel->consider_parallel =
6661 grouped_rel->consider_parallel;
6662 partially_grouped_rel->reloptkind = grouped_rel->reloptkind;
6663 partially_grouped_rel->serverid = grouped_rel->serverid;
6664 partially_grouped_rel->userid = grouped_rel->userid;
6665 partially_grouped_rel->useridiscurrent = grouped_rel->useridiscurrent;
6666 partially_grouped_rel->fdwroutine = grouped_rel->fdwroutine;
6667
6668 /*
6669 * Build target list for partial aggregate paths. These paths cannot just
6670 * emit the same tlist as regular aggregate paths, because (1) we must
6671 * include Vars and Aggrefs needed in HAVING, which might not appear in
6672 * the result tlist, and (2) the Aggrefs must be set in partial mode.
6673 */
6674 partially_grouped_rel->reltarget =
6675 make_partial_grouping_target(root, grouped_rel->reltarget,
6676 extra->havingQual);
6677
6678 if (!extra->partial_costs_set)
6679 {
6680 /*
6681 * Collect statistics about aggregates for estimating costs of
6682 * performing aggregation in parallel.
6683 */
6684 MemSet(agg_partial_costs, 0, sizeof(AggClauseCosts));
6685 MemSet(agg_final_costs, 0, sizeof(AggClauseCosts));
6686 if (parse->hasAggs)
6687 {
6688 List *partial_target_exprs;
6689
6690 /* partial phase */
6691 partial_target_exprs = partially_grouped_rel->reltarget->exprs;
6692 get_agg_clause_costs(root, (Node *) partial_target_exprs,
6693 AGGSPLIT_INITIAL_SERIAL,
6694 agg_partial_costs);
6695
6696 /* final phase */
6697 get_agg_clause_costs(root, (Node *) grouped_rel->reltarget->exprs,
6698 AGGSPLIT_FINAL_DESERIAL,
6699 agg_final_costs);
6700 get_agg_clause_costs(root, extra->havingQual,
6701 AGGSPLIT_FINAL_DESERIAL,
6702 agg_final_costs);
6703 }
6704
6705 extra->partial_costs_set = true;
6706 }
6707
6708 /* Estimate number of partial groups. */
6709 if (cheapest_total_path != NULL)
6710 dNumPartialGroups =
6711 get_number_of_groups(root,
6712 cheapest_total_path->rows,
6713 gd,
6714 extra->targetList);
6715 if (cheapest_partial_path != NULL)
6716 dNumPartialPartialGroups =
6717 get_number_of_groups(root,
6718 cheapest_partial_path->rows,
6719 gd,
6720 extra->targetList);
6721
6722 if (can_sort && cheapest_total_path != NULL)
6723 {
6724 /* This should have been checked previously */
6725 Assert(parse->hasAggs || parse->groupClause);
6726
6727 /*
6728 * Use any available suitably-sorted path as input, and also consider
6729 * sorting the cheapest partial path.
6730 */
6731 foreach(lc, input_rel->pathlist)
6732 {
6733 Path *path = (Path *) lfirst(lc);
6734 bool is_sorted;
6735
6736 is_sorted = pathkeys_contained_in(root->group_pathkeys,
6737 path->pathkeys);
6738 if (path == cheapest_total_path || is_sorted)
6739 {
6740 /* Sort the cheapest partial path, if it isn't already */
6741 if (!is_sorted)
6742 path = (Path *) create_sort_path(root,
6743 partially_grouped_rel,
6744 path,
6745 root->group_pathkeys,
6746 -1.0);
6747
6748 if (parse->hasAggs)
6749 add_path(partially_grouped_rel, (Path *)
6750 create_agg_path(root,
6751 partially_grouped_rel,
6752 path,
6753 partially_grouped_rel->reltarget,
6754 parse->groupClause ? AGG_SORTED : AGG_PLAIN,
6755 AGGSPLIT_INITIAL_SERIAL,
6756 parse->groupClause,
6757 NIL,
6758 agg_partial_costs,
6759 dNumPartialGroups));
6760 else
6761 add_path(partially_grouped_rel, (Path *)
6762 create_group_path(root,
6763 partially_grouped_rel,
6764 path,
6765 parse->groupClause,
6766 NIL,
6767 dNumPartialGroups));
6768 }
6769 }
6770 }
6771
6772 if (can_sort && cheapest_partial_path != NULL)
6773 {
6774 /* Similar to above logic, but for partial paths. */
6775 foreach(lc, input_rel->partial_pathlist)
6776 {
6777 Path *path = (Path *) lfirst(lc);
6778 bool is_sorted;
6779
6780 is_sorted = pathkeys_contained_in(root->group_pathkeys,
6781 path->pathkeys);
6782 if (path == cheapest_partial_path || is_sorted)
6783 {
6784 /* Sort the cheapest partial path, if it isn't already */
6785 if (!is_sorted)
6786 path = (Path *) create_sort_path(root,
6787 partially_grouped_rel,
6788 path,
6789 root->group_pathkeys,
6790 -1.0);
6791
6792 if (parse->hasAggs)
6793 add_partial_path(partially_grouped_rel, (Path *)
6794 create_agg_path(root,
6795 partially_grouped_rel,
6796 path,
6797 partially_grouped_rel->reltarget,
6798 parse->groupClause ? AGG_SORTED : AGG_PLAIN,
6799 AGGSPLIT_INITIAL_SERIAL,
6800 parse->groupClause,
6801 NIL,
6802 agg_partial_costs,
6803 dNumPartialPartialGroups));
6804 else
6805 add_partial_path(partially_grouped_rel, (Path *)
6806 create_group_path(root,
6807 partially_grouped_rel,
6808 path,
6809 parse->groupClause,
6810 NIL,
6811 dNumPartialPartialGroups));
6812 }
6813 }
6814 }
6815
6816 if (can_hash && cheapest_total_path != NULL)
6817 {
6818 double hashaggtablesize;
6819
6820 /* Checked above */
6821 Assert(parse->hasAggs || parse->groupClause);
6822
6823 hashaggtablesize =
6824 estimate_hashagg_tablesize(cheapest_total_path,
6825 agg_partial_costs,
6826 dNumPartialGroups);
6827
6828 /*
6829 * Tentatively produce a partial HashAgg Path, depending on if it
6830 * looks as if the hash table will fit in work_mem.
6831 */
6832 if (hashaggtablesize < work_mem * 1024L &&
6833 cheapest_total_path != NULL)
6834 {
6835 add_path(partially_grouped_rel, (Path *)
6836 create_agg_path(root,
6837 partially_grouped_rel,
6838 cheapest_total_path,
6839 partially_grouped_rel->reltarget,
6840 AGG_HASHED,
6841 AGGSPLIT_INITIAL_SERIAL,
6842 parse->groupClause,
6843 NIL,
6844 agg_partial_costs,
6845 dNumPartialGroups));
6846 }
6847 }
6848
6849 if (can_hash && cheapest_partial_path != NULL)
6850 {
6851 double hashaggtablesize;
6852
6853 hashaggtablesize =
6854 estimate_hashagg_tablesize(cheapest_partial_path,
6855 agg_partial_costs,
6856 dNumPartialPartialGroups);
6857
6858 /* Do the same for partial paths. */
6859 if (hashaggtablesize < work_mem * 1024L &&
6860 cheapest_partial_path != NULL)
6861 {
6862 add_partial_path(partially_grouped_rel, (Path *)
6863 create_agg_path(root,
6864 partially_grouped_rel,
6865 cheapest_partial_path,
6866 partially_grouped_rel->reltarget,
6867 AGG_HASHED,
6868 AGGSPLIT_INITIAL_SERIAL,
6869 parse->groupClause,
6870 NIL,
6871 agg_partial_costs,
6872 dNumPartialPartialGroups));
6873 }
6874 }
6875
6876 /*
6877 * If there is an FDW that's responsible for all baserels of the query,
6878 * let it consider adding partially grouped ForeignPaths.
6879 */
6880 if (partially_grouped_rel->fdwroutine &&
6881 partially_grouped_rel->fdwroutine->GetForeignUpperPaths)
6882 {
6883 FdwRoutine *fdwroutine = partially_grouped_rel->fdwroutine;
6884
6885 fdwroutine->GetForeignUpperPaths(root,
6886 UPPERREL_PARTIAL_GROUP_AGG,
6887 input_rel, partially_grouped_rel,
6888 extra);
6889 }
6890
6891 return partially_grouped_rel;
6892}
6893
6894/*
6895 * Generate Gather and Gather Merge paths for a grouping relation or partial
6896 * grouping relation.
6897 *
6898 * generate_gather_paths does most of the work, but we also consider a special
6899 * case: we could try sorting the data by the group_pathkeys and then applying
6900 * Gather Merge.
6901 *
6902 * NB: This function shouldn't be used for anything other than a grouped or
6903 * partially grouped relation not only because of the fact that it explicitly
6904 * references group_pathkeys but we pass "true" as the third argument to
6905 * generate_gather_paths().
6906 */
6907static void
6908gather_grouping_paths(PlannerInfo *root, RelOptInfo *rel)
6909{
6910 Path *cheapest_partial_path;
6911
6912 /* Try Gather for unordered paths and Gather Merge for ordered ones. */
6913 generate_gather_paths(root, rel, true);
6914
6915 /* Try cheapest partial path + explicit Sort + Gather Merge. */
6916 cheapest_partial_path = linitial(rel->partial_pathlist);
6917 if (!pathkeys_contained_in(root->group_pathkeys,
6918 cheapest_partial_path->pathkeys))
6919 {
6920 Path *path;
6921 double total_groups;
6922
6923 total_groups =
6924 cheapest_partial_path->rows * cheapest_partial_path->parallel_workers;
6925 path = (Path *) create_sort_path(root, rel, cheapest_partial_path,
6926 root->group_pathkeys,
6927 -1.0);
6928 path = (Path *)
6929 create_gather_merge_path(root,
6930 rel,
6931 path,
6932 rel->reltarget,
6933 root->group_pathkeys,
6934 NULL,
6935 &total_groups);
6936
6937 add_path(rel, path);
6938 }
6939}
6940
6941/*
6942 * can_partial_agg
6943 *
6944 * Determines whether or not partial grouping and/or aggregation is possible.
6945 * Returns true when possible, false otherwise.
6946 */
6947static bool
6948can_partial_agg(PlannerInfo *root, const AggClauseCosts *agg_costs)
6949{
6950 Query *parse = root->parse;
6951
6952 if (!parse->hasAggs && parse->groupClause == NIL)
6953 {
6954 /*
6955 * We don't know how to do parallel aggregation unless we have either
6956 * some aggregates or a grouping clause.
6957 */
6958 return false;
6959 }
6960 else if (parse->groupingSets)
6961 {
6962 /* We don't know how to do grouping sets in parallel. */
6963 return false;
6964 }
6965 else if (agg_costs->hasNonPartial || agg_costs->hasNonSerial)
6966 {
6967 /* Insufficient support for partial mode. */
6968 return false;
6969 }
6970
6971 /* Everything looks good. */
6972 return true;
6973}
6974
6975/*
6976 * apply_scanjoin_target_to_paths
6977 *
6978 * Adjust the final scan/join relation, and recursively all of its children,
6979 * to generate the final scan/join target. It would be more correct to model
6980 * this as a separate planning step with a new RelOptInfo at the toplevel and
6981 * for each child relation, but doing it this way is noticeably cheaper.
6982 * Maybe that problem can be solved at some point, but for now we do this.
6983 *
6984 * If tlist_same_exprs is true, then the scan/join target to be applied has
6985 * the same expressions as the existing reltarget, so we need only insert the
6986 * appropriate sortgroupref information. By avoiding the creation of
6987 * projection paths we save effort both immediately and at plan creation time.
6988 */
6989static void
6990apply_scanjoin_target_to_paths(PlannerInfo *root,
6991 RelOptInfo *rel,
6992 List *scanjoin_targets,
6993 List *scanjoin_targets_contain_srfs,
6994 bool scanjoin_target_parallel_safe,
6995 bool tlist_same_exprs)
6996{
6997 bool rel_is_partitioned = IS_PARTITIONED_REL(rel);
6998 PathTarget *scanjoin_target;
6999 ListCell *lc;
7000
7001 /* This recurses, so be paranoid. */
7002 check_stack_depth();
7003
7004 /*
7005 * If the rel is partitioned, we want to drop its existing paths and
7006 * generate new ones. This function would still be correct if we kept the
7007 * existing paths: we'd modify them to generate the correct target above
7008 * the partitioning Append, and then they'd compete on cost with paths
7009 * generating the target below the Append. However, in our current cost
7010 * model the latter way is always the same or cheaper cost, so modifying
7011 * the existing paths would just be useless work. Moreover, when the cost
7012 * is the same, varying roundoff errors might sometimes allow an existing
7013 * path to be picked, resulting in undesirable cross-platform plan
7014 * variations. So we drop old paths and thereby force the work to be done
7015 * below the Append, except in the case of a non-parallel-safe target.
7016 *
7017 * Some care is needed, because we have to allow generate_gather_paths to
7018 * see the old partial paths in the next stanza. Hence, zap the main
7019 * pathlist here, then allow generate_gather_paths to add path(s) to the
7020 * main list, and finally zap the partial pathlist.
7021 */
7022 if (rel_is_partitioned)
7023 rel->pathlist = NIL;
7024
7025 /*
7026 * If the scan/join target is not parallel-safe, partial paths cannot
7027 * generate it.
7028 */
7029 if (!scanjoin_target_parallel_safe)
7030 {
7031 /*
7032 * Since we can't generate the final scan/join target in parallel
7033 * workers, this is our last opportunity to use any partial paths that
7034 * exist; so build Gather path(s) that use them and emit whatever the
7035 * current reltarget is. We don't do this in the case where the
7036 * target is parallel-safe, since we will be able to generate superior
7037 * paths by doing it after the final scan/join target has been
7038 * applied.
7039 */
7040 generate_gather_paths(root, rel, false);
7041
7042 /* Can't use parallel query above this level. */
7043 rel->partial_pathlist = NIL;
7044 rel->consider_parallel = false;
7045 }
7046
7047 /* Finish dropping old paths for a partitioned rel, per comment above */
7048 if (rel_is_partitioned)
7049 rel->partial_pathlist = NIL;
7050
7051 /* Extract SRF-free scan/join target. */
7052 scanjoin_target = linitial_node(PathTarget, scanjoin_targets);
7053
7054 /*
7055 * Apply the SRF-free scan/join target to each existing path.
7056 *
7057 * If the tlist exprs are the same, we can just inject the sortgroupref
7058 * information into the existing pathtargets. Otherwise, replace each
7059 * path with a projection path that generates the SRF-free scan/join
7060 * target. This can't change the ordering of paths within rel->pathlist,
7061 * so we just modify the list in place.
7062 */
7063 foreach(lc, rel->pathlist)
7064 {
7065 Path *subpath = (Path *) lfirst(lc);
7066
7067 /* Shouldn't have any parameterized paths anymore */
7068 Assert(subpath->param_info == NULL);
7069
7070 if (tlist_same_exprs)
7071 subpath->pathtarget->sortgrouprefs =
7072 scanjoin_target->sortgrouprefs;
7073 else
7074 {
7075 Path *newpath;
7076
7077 newpath = (Path *) create_projection_path(root, rel, subpath,
7078 scanjoin_target);
7079 lfirst(lc) = newpath;
7080 }
7081 }
7082
7083 /* Likewise adjust the targets for any partial paths. */
7084 foreach(lc, rel->partial_pathlist)
7085 {
7086 Path *subpath = (Path *) lfirst(lc);
7087
7088 /* Shouldn't have any parameterized paths anymore */
7089 Assert(subpath->param_info == NULL);
7090
7091 if (tlist_same_exprs)
7092 subpath->pathtarget->sortgrouprefs =
7093 scanjoin_target->sortgrouprefs;
7094 else
7095 {
7096 Path *newpath;
7097
7098 newpath = (Path *) create_projection_path(root, rel, subpath,
7099 scanjoin_target);
7100 lfirst(lc) = newpath;
7101 }
7102 }
7103
7104 /*
7105 * Now, if final scan/join target contains SRFs, insert ProjectSetPath(s)
7106 * atop each existing path. (Note that this function doesn't look at the
7107 * cheapest-path fields, which is a good thing because they're bogus right
7108 * now.)
7109 */
7110 if (root->parse->hasTargetSRFs)
7111 adjust_paths_for_srfs(root, rel,
7112 scanjoin_targets,
7113 scanjoin_targets_contain_srfs);
7114
7115 /*
7116 * Update the rel's target to be the final (with SRFs) scan/join target.
7117 * This now matches the actual output of all the paths, and we might get
7118 * confused in createplan.c if they don't agree. We must do this now so
7119 * that any append paths made in the next part will use the correct
7120 * pathtarget (cf. create_append_path).
7121 *
7122 * Note that this is also necessary if GetForeignUpperPaths() gets called
7123 * on the final scan/join relation or on any of its children, since the
7124 * FDW might look at the rel's target to create ForeignPaths.
7125 */
7126 rel->reltarget = llast_node(PathTarget, scanjoin_targets);
7127
7128 /*
7129 * If the relation is partitioned, recursively apply the scan/join target
7130 * to all partitions, and generate brand-new Append paths in which the
7131 * scan/join target is computed below the Append rather than above it.
7132 * Since Append is not projection-capable, that might save a separate
7133 * Result node, and it also is important for partitionwise aggregate.
7134 */
7135 if (rel_is_partitioned)
7136 {
7137 List *live_children = NIL;
7138 int partition_idx;
7139
7140 /* Adjust each partition. */
7141 for (partition_idx = 0; partition_idx < rel->nparts; partition_idx++)
7142 {
7143 RelOptInfo *child_rel = rel->part_rels[partition_idx];
7144 AppendRelInfo **appinfos;
7145 int nappinfos;
7146 List *child_scanjoin_targets = NIL;
7147 ListCell *lc;
7148
7149 /* Pruned or dummy children can be ignored. */
7150 if (child_rel == NULL || IS_DUMMY_REL(child_rel))
7151 continue;
7152
7153 /* Translate scan/join targets for this child. */
7154 appinfos = find_appinfos_by_relids(root, child_rel->relids,
7155 &nappinfos);
7156 foreach(lc, scanjoin_targets)
7157 {
7158 PathTarget *target = lfirst_node(PathTarget, lc);
7159
7160 target = copy_pathtarget(target);
7161 target->exprs = (List *)
7162 adjust_appendrel_attrs(root,
7163 (Node *) target->exprs,
7164 nappinfos, appinfos);
7165 child_scanjoin_targets = lappend(child_scanjoin_targets,
7166 target);
7167 }
7168 pfree(appinfos);
7169
7170 /* Recursion does the real work. */
7171 apply_scanjoin_target_to_paths(root, child_rel,
7172 child_scanjoin_targets,
7173 scanjoin_targets_contain_srfs,
7174 scanjoin_target_parallel_safe,
7175 tlist_same_exprs);
7176
7177 /* Save non-dummy children for Append paths. */
7178 if (!IS_DUMMY_REL(child_rel))
7179 live_children = lappend(live_children, child_rel);
7180 }
7181
7182 /* Build new paths for this relation by appending child paths. */
7183 add_paths_to_append_rel(root, rel, live_children);
7184 }
7185
7186 /*
7187 * Consider generating Gather or Gather Merge paths. We must only do this
7188 * if the relation is parallel safe, and we don't do it for child rels to
7189 * avoid creating multiple Gather nodes within the same plan. We must do
7190 * this after all paths have been generated and before set_cheapest, since
7191 * one of the generated paths may turn out to be the cheapest one.
7192 */
7193 if (rel->consider_parallel && !IS_OTHER_REL(rel))
7194 generate_gather_paths(root, rel, false);
7195
7196 /*
7197 * Reassess which paths are the cheapest, now that we've potentially added
7198 * new Gather (or Gather Merge) and/or Append (or MergeAppend) paths to
7199 * this relation.
7200 */
7201 set_cheapest(rel);
7202}
7203
7204/*
7205 * create_partitionwise_grouping_paths
7206 *
7207 * If the partition keys of input relation are part of the GROUP BY clause, all
7208 * the rows belonging to a given group come from a single partition. This
7209 * allows aggregation/grouping over a partitioned relation to be broken down
7210 * into aggregation/grouping on each partition. This should be no worse, and
7211 * often better, than the normal approach.
7212 *
7213 * However, if the GROUP BY clause does not contain all the partition keys,
7214 * rows from a given group may be spread across multiple partitions. In that
7215 * case, we perform partial aggregation for each group, append the results,
7216 * and then finalize aggregation. This is less certain to win than the
7217 * previous case. It may win if the PartialAggregate stage greatly reduces
7218 * the number of groups, because fewer rows will pass through the Append node.
7219 * It may lose if we have lots of small groups.
7220 */
7221static void
7222create_partitionwise_grouping_paths(PlannerInfo *root,
7223 RelOptInfo *input_rel,
7224 RelOptInfo *grouped_rel,
7225 RelOptInfo *partially_grouped_rel,
7226 const AggClauseCosts *agg_costs,
7227 grouping_sets_data *gd,
7228 PartitionwiseAggregateType patype,
7229 GroupPathExtraData *extra)
7230{
7231 int nparts = input_rel->nparts;
7232 int cnt_parts;
7233 List *grouped_live_children = NIL;
7234 List *partially_grouped_live_children = NIL;
7235 PathTarget *target = grouped_rel->reltarget;
7236 bool partial_grouping_valid = true;
7237
7238 Assert(patype != PARTITIONWISE_AGGREGATE_NONE);
7239 Assert(patype != PARTITIONWISE_AGGREGATE_PARTIAL ||
7240 partially_grouped_rel != NULL);
7241
7242 /* Add paths for partitionwise aggregation/grouping. */
7243 for (cnt_parts = 0; cnt_parts < nparts; cnt_parts++)
7244 {
7245 RelOptInfo *child_input_rel = input_rel->part_rels[cnt_parts];
7246 PathTarget *child_target = copy_pathtarget(target);
7247 AppendRelInfo **appinfos;
7248 int nappinfos;
7249 GroupPathExtraData child_extra;
7250 RelOptInfo *child_grouped_rel;
7251 RelOptInfo *child_partially_grouped_rel;
7252
7253 /* Pruned or dummy children can be ignored. */
7254 if (child_input_rel == NULL || IS_DUMMY_REL(child_input_rel))
7255 continue;
7256
7257 /*
7258 * Copy the given "extra" structure as is and then override the
7259 * members specific to this child.
7260 */
7261 memcpy(&child_extra, extra, sizeof(child_extra));
7262
7263 appinfos = find_appinfos_by_relids(root, child_input_rel->relids,
7264 &nappinfos);
7265
7266 child_target->exprs = (List *)
7267 adjust_appendrel_attrs(root,
7268 (Node *) target->exprs,
7269 nappinfos, appinfos);
7270
7271 /* Translate havingQual and targetList. */
7272 child_extra.havingQual = (Node *)
7273 adjust_appendrel_attrs(root,
7274 extra->havingQual,
7275 nappinfos, appinfos);
7276 child_extra.targetList = (List *)
7277 adjust_appendrel_attrs(root,
7278 (Node *) extra->targetList,
7279 nappinfos, appinfos);
7280
7281 /*
7282 * extra->patype was the value computed for our parent rel; patype is
7283 * the value for this relation. For the child, our value is its
7284 * parent rel's value.
7285 */
7286 child_extra.patype = patype;
7287
7288 /*
7289 * Create grouping relation to hold fully aggregated grouping and/or
7290 * aggregation paths for the child.
7291 */
7292 child_grouped_rel = make_grouping_rel(root, child_input_rel,
7293 child_target,
7294 extra->target_parallel_safe,
7295 child_extra.havingQual);
7296
7297 /* Create grouping paths for this child relation. */
7298 create_ordinary_grouping_paths(root, child_input_rel,
7299 child_grouped_rel,
7300 agg_costs, gd, &child_extra,
7301 &child_partially_grouped_rel);
7302
7303 if (child_partially_grouped_rel)
7304 {
7305 partially_grouped_live_children =
7306 lappend(partially_grouped_live_children,
7307 child_partially_grouped_rel);
7308 }
7309 else
7310 partial_grouping_valid = false;
7311
7312 if (patype == PARTITIONWISE_AGGREGATE_FULL)
7313 {
7314 set_cheapest(child_grouped_rel);
7315 grouped_live_children = lappend(grouped_live_children,
7316 child_grouped_rel);
7317 }
7318
7319 pfree(appinfos);
7320 }
7321
7322 /*
7323 * Try to create append paths for partially grouped children. For full
7324 * partitionwise aggregation, we might have paths in the partial_pathlist
7325 * if parallel aggregation is possible. For partial partitionwise
7326 * aggregation, we may have paths in both pathlist and partial_pathlist.
7327 *
7328 * NB: We must have a partially grouped path for every child in order to
7329 * generate a partially grouped path for this relation.
7330 */
7331 if (partially_grouped_rel && partial_grouping_valid)
7332 {
7333 Assert(partially_grouped_live_children != NIL);
7334
7335 add_paths_to_append_rel(root, partially_grouped_rel,
7336 partially_grouped_live_children);
7337
7338 /*
7339 * We need call set_cheapest, since the finalization step will use the
7340 * cheapest path from the rel.
7341 */
7342 if (partially_grouped_rel->pathlist)
7343 set_cheapest(partially_grouped_rel);
7344 }
7345
7346 /* If possible, create append paths for fully grouped children. */
7347 if (patype == PARTITIONWISE_AGGREGATE_FULL)
7348 {
7349 Assert(grouped_live_children != NIL);
7350
7351 add_paths_to_append_rel(root, grouped_rel, grouped_live_children);
7352 }
7353}
7354
7355/*
7356 * group_by_has_partkey
7357 *
7358 * Returns true, if all the partition keys of the given relation are part of
7359 * the GROUP BY clauses, false otherwise.
7360 */
7361static bool
7362group_by_has_partkey(RelOptInfo *input_rel,
7363 List *targetList,
7364 List *groupClause)
7365{
7366 List *groupexprs = get_sortgrouplist_exprs(groupClause, targetList);
7367 int cnt = 0;
7368 int partnatts;
7369
7370 /* Input relation should be partitioned. */
7371 Assert(input_rel->part_scheme);
7372
7373 /* Rule out early, if there are no partition keys present. */
7374 if (!input_rel->partexprs)
7375 return false;
7376
7377 partnatts = input_rel->part_scheme->partnatts;
7378
7379 for (cnt = 0; cnt < partnatts; cnt++)
7380 {
7381 List *partexprs = input_rel->partexprs[cnt];
7382 ListCell *lc;
7383 bool found = false;
7384
7385 foreach(lc, partexprs)
7386 {
7387 Expr *partexpr = lfirst(lc);
7388
7389 if (list_member(groupexprs, partexpr))
7390 {
7391 found = true;
7392 break;
7393 }
7394 }
7395
7396 /*
7397 * If none of the partition key expressions match with any of the
7398 * GROUP BY expression, return false.
7399 */
7400 if (!found)
7401 return false;
7402 }
7403
7404 return true;
7405}
7406