1/*-------------------------------------------------------------------------
2 *
3 * partition.c
4 * Partitioning related data structures and functions.
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/catalog/partition.c
12 *
13 *-------------------------------------------------------------------------
14*/
15#include "postgres.h"
16
17#include "access/genam.h"
18#include "access/htup_details.h"
19#include "access/table.h"
20#include "access/tupconvert.h"
21#include "access/sysattr.h"
22#include "catalog/indexing.h"
23#include "catalog/partition.h"
24#include "catalog/pg_inherits.h"
25#include "catalog/pg_partitioned_table.h"
26#include "nodes/makefuncs.h"
27#include "optimizer/optimizer.h"
28#include "partitioning/partbounds.h"
29#include "rewrite/rewriteManip.h"
30#include "utils/fmgroids.h"
31#include "utils/partcache.h"
32#include "utils/rel.h"
33#include "utils/syscache.h"
34
35
36static Oid get_partition_parent_worker(Relation inhRel, Oid relid);
37static void get_partition_ancestors_worker(Relation inhRel, Oid relid,
38 List **ancestors);
39
40/*
41 * get_partition_parent
42 * Obtain direct parent of given relation
43 *
44 * Returns inheritance parent of a partition by scanning pg_inherits
45 *
46 * Note: Because this function assumes that the relation whose OID is passed
47 * as an argument will have precisely one parent, it should only be called
48 * when it is known that the relation is a partition.
49 */
50Oid
51get_partition_parent(Oid relid)
52{
53 Relation catalogRelation;
54 Oid result;
55
56 catalogRelation = table_open(InheritsRelationId, AccessShareLock);
57
58 result = get_partition_parent_worker(catalogRelation, relid);
59
60 if (!OidIsValid(result))
61 elog(ERROR, "could not find tuple for parent of relation %u", relid);
62
63 table_close(catalogRelation, AccessShareLock);
64
65 return result;
66}
67
68/*
69 * get_partition_parent_worker
70 * Scan the pg_inherits relation to return the OID of the parent of the
71 * given relation
72 */
73static Oid
74get_partition_parent_worker(Relation inhRel, Oid relid)
75{
76 SysScanDesc scan;
77 ScanKeyData key[2];
78 Oid result = InvalidOid;
79 HeapTuple tuple;
80
81 ScanKeyInit(&key[0],
82 Anum_pg_inherits_inhrelid,
83 BTEqualStrategyNumber, F_OIDEQ,
84 ObjectIdGetDatum(relid));
85 ScanKeyInit(&key[1],
86 Anum_pg_inherits_inhseqno,
87 BTEqualStrategyNumber, F_INT4EQ,
88 Int32GetDatum(1));
89
90 scan = systable_beginscan(inhRel, InheritsRelidSeqnoIndexId, true,
91 NULL, 2, key);
92 tuple = systable_getnext(scan);
93 if (HeapTupleIsValid(tuple))
94 {
95 Form_pg_inherits form = (Form_pg_inherits) GETSTRUCT(tuple);
96
97 result = form->inhparent;
98 }
99
100 systable_endscan(scan);
101
102 return result;
103}
104
105/*
106 * get_partition_ancestors
107 * Obtain ancestors of given relation
108 *
109 * Returns a list of ancestors of the given relation.
110 *
111 * Note: Because this function assumes that the relation whose OID is passed
112 * as an argument and each ancestor will have precisely one parent, it should
113 * only be called when it is known that the relation is a partition.
114 */
115List *
116get_partition_ancestors(Oid relid)
117{
118 List *result = NIL;
119 Relation inhRel;
120
121 inhRel = table_open(InheritsRelationId, AccessShareLock);
122
123 get_partition_ancestors_worker(inhRel, relid, &result);
124
125 table_close(inhRel, AccessShareLock);
126
127 return result;
128}
129
130/*
131 * get_partition_ancestors_worker
132 * recursive worker for get_partition_ancestors
133 */
134static void
135get_partition_ancestors_worker(Relation inhRel, Oid relid, List **ancestors)
136{
137 Oid parentOid;
138
139 /* Recursion ends at the topmost level, ie., when there's no parent */
140 parentOid = get_partition_parent_worker(inhRel, relid);
141 if (parentOid == InvalidOid)
142 return;
143
144 *ancestors = lappend_oid(*ancestors, parentOid);
145 get_partition_ancestors_worker(inhRel, parentOid, ancestors);
146}
147
148/*
149 * index_get_partition
150 * Return the OID of index of the given partition that is a child
151 * of the given index, or InvalidOid if there isn't one.
152 */
153Oid
154index_get_partition(Relation partition, Oid indexId)
155{
156 List *idxlist = RelationGetIndexList(partition);
157 ListCell *l;
158
159 foreach(l, idxlist)
160 {
161 Oid partIdx = lfirst_oid(l);
162 HeapTuple tup;
163 Form_pg_class classForm;
164 bool ispartition;
165
166 tup = SearchSysCache1(RELOID, ObjectIdGetDatum(partIdx));
167 if (!HeapTupleIsValid(tup))
168 elog(ERROR, "cache lookup failed for relation %u", partIdx);
169 classForm = (Form_pg_class) GETSTRUCT(tup);
170 ispartition = classForm->relispartition;
171 ReleaseSysCache(tup);
172 if (!ispartition)
173 continue;
174 if (get_partition_parent(lfirst_oid(l)) == indexId)
175 {
176 list_free(idxlist);
177 return partIdx;
178 }
179 }
180
181 return InvalidOid;
182}
183
184/*
185 * map_partition_varattnos - maps varattno of any Vars in expr from the
186 * attno's of 'from_rel' to the attno's of 'to_rel' partition, each of which
187 * may be either a leaf partition or a partitioned table, but both of which
188 * must be from the same partitioning hierarchy.
189 *
190 * Even though all of the same column names must be present in all relations
191 * in the hierarchy, and they must also have the same types, the attnos may
192 * be different.
193 *
194 * If found_whole_row is not NULL, *found_whole_row returns whether a
195 * whole-row variable was found in the input expression.
196 *
197 * Note: this will work on any node tree, so really the argument and result
198 * should be declared "Node *". But a substantial majority of the callers
199 * are working on Lists, so it's less messy to do the casts internally.
200 */
201List *
202map_partition_varattnos(List *expr, int fromrel_varno,
203 Relation to_rel, Relation from_rel,
204 bool *found_whole_row)
205{
206 bool my_found_whole_row = false;
207
208 if (expr != NIL)
209 {
210 AttrNumber *part_attnos;
211
212 part_attnos = convert_tuples_by_name_map(RelationGetDescr(to_rel),
213 RelationGetDescr(from_rel),
214 gettext_noop("could not convert row type"));
215 expr = (List *) map_variable_attnos((Node *) expr,
216 fromrel_varno, 0,
217 part_attnos,
218 RelationGetDescr(from_rel)->natts,
219 RelationGetForm(to_rel)->reltype,
220 &my_found_whole_row);
221 }
222
223 if (found_whole_row)
224 *found_whole_row = my_found_whole_row;
225
226 return expr;
227}
228
229/*
230 * Checks if any of the 'attnums' is a partition key attribute for rel
231 *
232 * Sets *used_in_expr if any of the 'attnums' is found to be referenced in some
233 * partition key expression. It's possible for a column to be both used
234 * directly and as part of an expression; if that happens, *used_in_expr may
235 * end up as either true or false. That's OK for current uses of this
236 * function, because *used_in_expr is only used to tailor the error message
237 * text.
238 */
239bool
240has_partition_attrs(Relation rel, Bitmapset *attnums, bool *used_in_expr)
241{
242 PartitionKey key;
243 int partnatts;
244 List *partexprs;
245 ListCell *partexprs_item;
246 int i;
247
248 if (attnums == NULL || rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
249 return false;
250
251 key = RelationGetPartitionKey(rel);
252 partnatts = get_partition_natts(key);
253 partexprs = get_partition_exprs(key);
254
255 partexprs_item = list_head(partexprs);
256 for (i = 0; i < partnatts; i++)
257 {
258 AttrNumber partattno = get_partition_col_attnum(key, i);
259
260 if (partattno != 0)
261 {
262 if (bms_is_member(partattno - FirstLowInvalidHeapAttributeNumber,
263 attnums))
264 {
265 if (used_in_expr)
266 *used_in_expr = false;
267 return true;
268 }
269 }
270 else
271 {
272 /* Arbitrary expression */
273 Node *expr = (Node *) lfirst(partexprs_item);
274 Bitmapset *expr_attrs = NULL;
275
276 /* Find all attributes referenced */
277 pull_varattnos(expr, 1, &expr_attrs);
278 partexprs_item = lnext(partexprs_item);
279
280 if (bms_overlap(attnums, expr_attrs))
281 {
282 if (used_in_expr)
283 *used_in_expr = true;
284 return true;
285 }
286 }
287 }
288
289 return false;
290}
291
292/*
293 * get_default_partition_oid
294 *
295 * Given a relation OID, return the OID of the default partition, if one
296 * exists. Use get_default_oid_from_partdesc where possible, for
297 * efficiency.
298 */
299Oid
300get_default_partition_oid(Oid parentId)
301{
302 HeapTuple tuple;
303 Oid defaultPartId = InvalidOid;
304
305 tuple = SearchSysCache1(PARTRELID, ObjectIdGetDatum(parentId));
306
307 if (HeapTupleIsValid(tuple))
308 {
309 Form_pg_partitioned_table part_table_form;
310
311 part_table_form = (Form_pg_partitioned_table) GETSTRUCT(tuple);
312 defaultPartId = part_table_form->partdefid;
313 ReleaseSysCache(tuple);
314 }
315
316 return defaultPartId;
317}
318
319/*
320 * update_default_partition_oid
321 *
322 * Update pg_partitioned_table.partdefid with a new default partition OID.
323 */
324void
325update_default_partition_oid(Oid parentId, Oid defaultPartId)
326{
327 HeapTuple tuple;
328 Relation pg_partitioned_table;
329 Form_pg_partitioned_table part_table_form;
330
331 pg_partitioned_table = table_open(PartitionedRelationId, RowExclusiveLock);
332
333 tuple = SearchSysCacheCopy1(PARTRELID, ObjectIdGetDatum(parentId));
334
335 if (!HeapTupleIsValid(tuple))
336 elog(ERROR, "cache lookup failed for partition key of relation %u",
337 parentId);
338
339 part_table_form = (Form_pg_partitioned_table) GETSTRUCT(tuple);
340 part_table_form->partdefid = defaultPartId;
341 CatalogTupleUpdate(pg_partitioned_table, &tuple->t_self, tuple);
342
343 heap_freetuple(tuple);
344 table_close(pg_partitioned_table, RowExclusiveLock);
345}
346
347/*
348 * get_proposed_default_constraint
349 *
350 * This function returns the negation of new_part_constraints, which
351 * would be an integral part of the default partition constraints after
352 * addition of the partition to which the new_part_constraints belongs.
353 */
354List *
355get_proposed_default_constraint(List *new_part_constraints)
356{
357 Expr *defPartConstraint;
358
359 defPartConstraint = make_ands_explicit(new_part_constraints);
360
361 /*
362 * Derive the partition constraints of default partition by negating the
363 * given partition constraints. The partition constraint never evaluates
364 * to NULL, so negating it like this is safe.
365 */
366 defPartConstraint = makeBoolExpr(NOT_EXPR,
367 list_make1(defPartConstraint),
368 -1);
369
370 /* Simplify, to put the negated expression into canonical form */
371 defPartConstraint =
372 (Expr *) eval_const_expressions(NULL,
373 (Node *) defPartConstraint);
374 defPartConstraint = canonicalize_qual(defPartConstraint, true);
375
376 return make_ands_implicit(defPartConstraint);
377}
378