1/*-------------------------------------------------------------------------
2 *
3 * rewriteheap.c
4 * Support functions to rewrite tables.
5 *
6 * These functions provide a facility to completely rewrite a heap, while
7 * preserving visibility information and update chains.
8 *
9 * INTERFACE
10 *
11 * The caller is responsible for creating the new heap, all catalog
12 * changes, supplying the tuples to be written to the new heap, and
13 * rebuilding indexes. The caller must hold AccessExclusiveLock on the
14 * target table, because we assume no one else is writing into it.
15 *
16 * To use the facility:
17 *
18 * begin_heap_rewrite
19 * while (fetch next tuple)
20 * {
21 * if (tuple is dead)
22 * rewrite_heap_dead_tuple
23 * else
24 * {
25 * // do any transformations here if required
26 * rewrite_heap_tuple
27 * }
28 * }
29 * end_heap_rewrite
30 *
31 * The contents of the new relation shouldn't be relied on until after
32 * end_heap_rewrite is called.
33 *
34 *
35 * IMPLEMENTATION
36 *
37 * This would be a fairly trivial affair, except that we need to maintain
38 * the ctid chains that link versions of an updated tuple together.
39 * Since the newly stored tuples will have tids different from the original
40 * ones, if we just copied t_ctid fields to the new table the links would
41 * be wrong. When we are required to copy a (presumably recently-dead or
42 * delete-in-progress) tuple whose ctid doesn't point to itself, we have
43 * to substitute the correct ctid instead.
44 *
45 * For each ctid reference from A -> B, we might encounter either A first
46 * or B first. (Note that a tuple in the middle of a chain is both A and B
47 * of different pairs.)
48 *
49 * If we encounter A first, we'll store the tuple in the unresolved_tups
50 * hash table. When we later encounter B, we remove A from the hash table,
51 * fix the ctid to point to the new location of B, and insert both A and B
52 * to the new heap.
53 *
54 * If we encounter B first, we can insert B to the new heap right away.
55 * We then add an entry to the old_new_tid_map hash table showing B's
56 * original tid (in the old heap) and new tid (in the new heap).
57 * When we later encounter A, we get the new location of B from the table,
58 * and can write A immediately with the correct ctid.
59 *
60 * Entries in the hash tables can be removed as soon as the later tuple
61 * is encountered. That helps to keep the memory usage down. At the end,
62 * both tables are usually empty; we should have encountered both A and B
63 * of each pair. However, it's possible for A to be RECENTLY_DEAD and B
64 * entirely DEAD according to HeapTupleSatisfiesVacuum, because the test
65 * for deadness using OldestXmin is not exact. In such a case we might
66 * encounter B first, and skip it, and find A later. Then A would be added
67 * to unresolved_tups, and stay there until end of the rewrite. Since
68 * this case is very unusual, we don't worry about the memory usage.
69 *
70 * Using in-memory hash tables means that we use some memory for each live
71 * update chain in the table, from the time we find one end of the
72 * reference until we find the other end. That shouldn't be a problem in
73 * practice, but if you do something like an UPDATE without a where-clause
74 * on a large table, and then run CLUSTER in the same transaction, you
75 * could run out of memory. It doesn't seem worthwhile to add support for
76 * spill-to-disk, as there shouldn't be that many RECENTLY_DEAD tuples in a
77 * table under normal circumstances. Furthermore, in the typical scenario
78 * of CLUSTERing on an unchanging key column, we'll see all the versions
79 * of a given tuple together anyway, and so the peak memory usage is only
80 * proportional to the number of RECENTLY_DEAD versions of a single row, not
81 * in the whole table. Note that if we do fail halfway through a CLUSTER,
82 * the old table is still valid, so failure is not catastrophic.
83 *
84 * We can't use the normal heap_insert function to insert into the new
85 * heap, because heap_insert overwrites the visibility information.
86 * We use a special-purpose raw_heap_insert function instead, which
87 * is optimized for bulk inserting a lot of tuples, knowing that we have
88 * exclusive access to the heap. raw_heap_insert builds new pages in
89 * local storage. When a page is full, or at the end of the process,
90 * we insert it to WAL as a single record and then write it to disk
91 * directly through smgr. Note, however, that any data sent to the new
92 * heap's TOAST table will go through the normal bufmgr.
93 *
94 *
95 * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
96 * Portions Copyright (c) 1994-5, Regents of the University of California
97 *
98 * IDENTIFICATION
99 * src/backend/access/heap/rewriteheap.c
100 *
101 *-------------------------------------------------------------------------
102 */
103#include "postgres.h"
104
105#include <sys/stat.h>
106#include <unistd.h>
107
108#include "miscadmin.h"
109
110#include "access/heapam.h"
111#include "access/heapam_xlog.h"
112#include "access/rewriteheap.h"
113#include "access/transam.h"
114#include "access/tuptoaster.h"
115#include "access/xact.h"
116#include "access/xloginsert.h"
117
118#include "catalog/catalog.h"
119
120#include "lib/ilist.h"
121
122#include "pgstat.h"
123
124#include "replication/logical.h"
125#include "replication/slot.h"
126
127#include "storage/bufmgr.h"
128#include "storage/fd.h"
129#include "storage/smgr.h"
130
131#include "utils/memutils.h"
132#include "utils/rel.h"
133
134#include "storage/procarray.h"
135
136/*
137 * State associated with a rewrite operation. This is opaque to the user
138 * of the rewrite facility.
139 */
140typedef struct RewriteStateData
141{
142 Relation rs_old_rel; /* source heap */
143 Relation rs_new_rel; /* destination heap */
144 Page rs_buffer; /* page currently being built */
145 BlockNumber rs_blockno; /* block where page will go */
146 bool rs_buffer_valid; /* T if any tuples in buffer */
147 bool rs_use_wal; /* must we WAL-log inserts? */
148 bool rs_logical_rewrite; /* do we need to do logical rewriting */
149 TransactionId rs_oldest_xmin; /* oldest xmin used by caller to determine
150 * tuple visibility */
151 TransactionId rs_freeze_xid; /* Xid that will be used as freeze cutoff
152 * point */
153 TransactionId rs_logical_xmin; /* Xid that will be used as cutoff point
154 * for logical rewrites */
155 MultiXactId rs_cutoff_multi; /* MultiXactId that will be used as cutoff
156 * point for multixacts */
157 MemoryContext rs_cxt; /* for hash tables and entries and tuples in
158 * them */
159 XLogRecPtr rs_begin_lsn; /* XLogInsertLsn when starting the rewrite */
160 HTAB *rs_unresolved_tups; /* unmatched A tuples */
161 HTAB *rs_old_new_tid_map; /* unmatched B tuples */
162 HTAB *rs_logical_mappings; /* logical remapping files */
163 uint32 rs_num_rewrite_mappings; /* # in memory mappings */
164} RewriteStateData;
165
166/*
167 * The lookup keys for the hash tables are tuple TID and xmin (we must check
168 * both to avoid false matches from dead tuples). Beware that there is
169 * probably some padding space in this struct; it must be zeroed out for
170 * correct hashtable operation.
171 */
172typedef struct
173{
174 TransactionId xmin; /* tuple xmin */
175 ItemPointerData tid; /* tuple location in old heap */
176} TidHashKey;
177
178/*
179 * Entry structures for the hash tables
180 */
181typedef struct
182{
183 TidHashKey key; /* expected xmin/old location of B tuple */
184 ItemPointerData old_tid; /* A's location in the old heap */
185 HeapTuple tuple; /* A's tuple contents */
186} UnresolvedTupData;
187
188typedef UnresolvedTupData *UnresolvedTup;
189
190typedef struct
191{
192 TidHashKey key; /* actual xmin/old location of B tuple */
193 ItemPointerData new_tid; /* where we put it in the new heap */
194} OldToNewMappingData;
195
196typedef OldToNewMappingData *OldToNewMapping;
197
198/*
199 * In-Memory data for an xid that might need logical remapping entries
200 * to be logged.
201 */
202typedef struct RewriteMappingFile
203{
204 TransactionId xid; /* xid that might need to see the row */
205 int vfd; /* fd of mappings file */
206 off_t off; /* how far have we written yet */
207 uint32 num_mappings; /* number of in-memory mappings */
208 dlist_head mappings; /* list of in-memory mappings */
209 char path[MAXPGPATH]; /* path, for error messages */
210} RewriteMappingFile;
211
212/*
213 * A single In-Memory logical rewrite mapping, hanging off
214 * RewriteMappingFile->mappings.
215 */
216typedef struct RewriteMappingDataEntry
217{
218 LogicalRewriteMappingData map; /* map between old and new location of the
219 * tuple */
220 dlist_node node;
221} RewriteMappingDataEntry;
222
223
224/* prototypes for internal functions */
225static void raw_heap_insert(RewriteState state, HeapTuple tup);
226
227/* internal logical remapping prototypes */
228static void logical_begin_heap_rewrite(RewriteState state);
229static void logical_rewrite_heap_tuple(RewriteState state, ItemPointerData old_tid, HeapTuple new_tuple);
230static void logical_end_heap_rewrite(RewriteState state);
231
232
233/*
234 * Begin a rewrite of a table
235 *
236 * old_heap old, locked heap relation tuples will be read from
237 * new_heap new, locked heap relation to insert tuples to
238 * oldest_xmin xid used by the caller to determine which tuples are dead
239 * freeze_xid xid before which tuples will be frozen
240 * min_multi multixact before which multis will be removed
241 * use_wal should the inserts to the new heap be WAL-logged?
242 *
243 * Returns an opaque RewriteState, allocated in current memory context,
244 * to be used in subsequent calls to the other functions.
245 */
246RewriteState
247begin_heap_rewrite(Relation old_heap, Relation new_heap, TransactionId oldest_xmin,
248 TransactionId freeze_xid, MultiXactId cutoff_multi,
249 bool use_wal)
250{
251 RewriteState state;
252 MemoryContext rw_cxt;
253 MemoryContext old_cxt;
254 HASHCTL hash_ctl;
255
256 /*
257 * To ease cleanup, make a separate context that will contain the
258 * RewriteState struct itself plus all subsidiary data.
259 */
260 rw_cxt = AllocSetContextCreate(CurrentMemoryContext,
261 "Table rewrite",
262 ALLOCSET_DEFAULT_SIZES);
263 old_cxt = MemoryContextSwitchTo(rw_cxt);
264
265 /* Create and fill in the state struct */
266 state = palloc0(sizeof(RewriteStateData));
267
268 state->rs_old_rel = old_heap;
269 state->rs_new_rel = new_heap;
270 state->rs_buffer = (Page) palloc(BLCKSZ);
271 /* new_heap needn't be empty, just locked */
272 state->rs_blockno = RelationGetNumberOfBlocks(new_heap);
273 state->rs_buffer_valid = false;
274 state->rs_use_wal = use_wal;
275 state->rs_oldest_xmin = oldest_xmin;
276 state->rs_freeze_xid = freeze_xid;
277 state->rs_cutoff_multi = cutoff_multi;
278 state->rs_cxt = rw_cxt;
279
280 /* Initialize hash tables used to track update chains */
281 memset(&hash_ctl, 0, sizeof(hash_ctl));
282 hash_ctl.keysize = sizeof(TidHashKey);
283 hash_ctl.entrysize = sizeof(UnresolvedTupData);
284 hash_ctl.hcxt = state->rs_cxt;
285
286 state->rs_unresolved_tups =
287 hash_create("Rewrite / Unresolved ctids",
288 128, /* arbitrary initial size */
289 &hash_ctl,
290 HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
291
292 hash_ctl.entrysize = sizeof(OldToNewMappingData);
293
294 state->rs_old_new_tid_map =
295 hash_create("Rewrite / Old to new tid map",
296 128, /* arbitrary initial size */
297 &hash_ctl,
298 HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
299
300 MemoryContextSwitchTo(old_cxt);
301
302 logical_begin_heap_rewrite(state);
303
304 return state;
305}
306
307/*
308 * End a rewrite.
309 *
310 * state and any other resources are freed.
311 */
312void
313end_heap_rewrite(RewriteState state)
314{
315 HASH_SEQ_STATUS seq_status;
316 UnresolvedTup unresolved;
317
318 /*
319 * Write any remaining tuples in the UnresolvedTups table. If we have any
320 * left, they should in fact be dead, but let's err on the safe side.
321 */
322 hash_seq_init(&seq_status, state->rs_unresolved_tups);
323
324 while ((unresolved = hash_seq_search(&seq_status)) != NULL)
325 {
326 ItemPointerSetInvalid(&unresolved->tuple->t_data->t_ctid);
327 raw_heap_insert(state, unresolved->tuple);
328 }
329
330 /* Write the last page, if any */
331 if (state->rs_buffer_valid)
332 {
333 if (state->rs_use_wal)
334 log_newpage(&state->rs_new_rel->rd_node,
335 MAIN_FORKNUM,
336 state->rs_blockno,
337 state->rs_buffer,
338 true);
339 RelationOpenSmgr(state->rs_new_rel);
340
341 PageSetChecksumInplace(state->rs_buffer, state->rs_blockno);
342
343 smgrextend(state->rs_new_rel->rd_smgr, MAIN_FORKNUM, state->rs_blockno,
344 (char *) state->rs_buffer, true);
345 }
346
347 /*
348 * If the rel is WAL-logged, must fsync before commit. We use heap_sync
349 * to ensure that the toast table gets fsync'd too.
350 *
351 * It's obvious that we must do this when not WAL-logging. It's less
352 * obvious that we have to do it even if we did WAL-log the pages. The
353 * reason is the same as in storage.c's RelationCopyStorage(): we're
354 * writing data that's not in shared buffers, and so a CHECKPOINT
355 * occurring during the rewriteheap operation won't have fsync'd data we
356 * wrote before the checkpoint.
357 */
358 if (RelationNeedsWAL(state->rs_new_rel))
359 heap_sync(state->rs_new_rel);
360
361 logical_end_heap_rewrite(state);
362
363 /* Deleting the context frees everything */
364 MemoryContextDelete(state->rs_cxt);
365}
366
367/*
368 * Add a tuple to the new heap.
369 *
370 * Visibility information is copied from the original tuple, except that
371 * we "freeze" very-old tuples. Note that since we scribble on new_tuple,
372 * it had better be temp storage not a pointer to the original tuple.
373 *
374 * state opaque state as returned by begin_heap_rewrite
375 * old_tuple original tuple in the old heap
376 * new_tuple new, rewritten tuple to be inserted to new heap
377 */
378void
379rewrite_heap_tuple(RewriteState state,
380 HeapTuple old_tuple, HeapTuple new_tuple)
381{
382 MemoryContext old_cxt;
383 ItemPointerData old_tid;
384 TidHashKey hashkey;
385 bool found;
386 bool free_new;
387
388 old_cxt = MemoryContextSwitchTo(state->rs_cxt);
389
390 /*
391 * Copy the original tuple's visibility information into new_tuple.
392 *
393 * XXX we might later need to copy some t_infomask2 bits, too? Right now,
394 * we intentionally clear the HOT status bits.
395 */
396 memcpy(&new_tuple->t_data->t_choice.t_heap,
397 &old_tuple->t_data->t_choice.t_heap,
398 sizeof(HeapTupleFields));
399
400 new_tuple->t_data->t_infomask &= ~HEAP_XACT_MASK;
401 new_tuple->t_data->t_infomask2 &= ~HEAP2_XACT_MASK;
402 new_tuple->t_data->t_infomask |=
403 old_tuple->t_data->t_infomask & HEAP_XACT_MASK;
404
405 /*
406 * While we have our hands on the tuple, we may as well freeze any
407 * eligible xmin or xmax, so that future VACUUM effort can be saved.
408 */
409 heap_freeze_tuple(new_tuple->t_data,
410 state->rs_old_rel->rd_rel->relfrozenxid,
411 state->rs_old_rel->rd_rel->relminmxid,
412 state->rs_freeze_xid,
413 state->rs_cutoff_multi);
414
415 /*
416 * Invalid ctid means that ctid should point to the tuple itself. We'll
417 * override it later if the tuple is part of an update chain.
418 */
419 ItemPointerSetInvalid(&new_tuple->t_data->t_ctid);
420
421 /*
422 * If the tuple has been updated, check the old-to-new mapping hash table.
423 */
424 if (!((old_tuple->t_data->t_infomask & HEAP_XMAX_INVALID) ||
425 HeapTupleHeaderIsOnlyLocked(old_tuple->t_data)) &&
426 !HeapTupleHeaderIndicatesMovedPartitions(old_tuple->t_data) &&
427 !(ItemPointerEquals(&(old_tuple->t_self),
428 &(old_tuple->t_data->t_ctid))))
429 {
430 OldToNewMapping mapping;
431
432 memset(&hashkey, 0, sizeof(hashkey));
433 hashkey.xmin = HeapTupleHeaderGetUpdateXid(old_tuple->t_data);
434 hashkey.tid = old_tuple->t_data->t_ctid;
435
436 mapping = (OldToNewMapping)
437 hash_search(state->rs_old_new_tid_map, &hashkey,
438 HASH_FIND, NULL);
439
440 if (mapping != NULL)
441 {
442 /*
443 * We've already copied the tuple that t_ctid points to, so we can
444 * set the ctid of this tuple to point to the new location, and
445 * insert it right away.
446 */
447 new_tuple->t_data->t_ctid = mapping->new_tid;
448
449 /* We don't need the mapping entry anymore */
450 hash_search(state->rs_old_new_tid_map, &hashkey,
451 HASH_REMOVE, &found);
452 Assert(found);
453 }
454 else
455 {
456 /*
457 * We haven't seen the tuple t_ctid points to yet. Stash this
458 * tuple into unresolved_tups to be written later.
459 */
460 UnresolvedTup unresolved;
461
462 unresolved = hash_search(state->rs_unresolved_tups, &hashkey,
463 HASH_ENTER, &found);
464 Assert(!found);
465
466 unresolved->old_tid = old_tuple->t_self;
467 unresolved->tuple = heap_copytuple(new_tuple);
468
469 /*
470 * We can't do anything more now, since we don't know where the
471 * tuple will be written.
472 */
473 MemoryContextSwitchTo(old_cxt);
474 return;
475 }
476 }
477
478 /*
479 * Now we will write the tuple, and then check to see if it is the B tuple
480 * in any new or known pair. When we resolve a known pair, we will be
481 * able to write that pair's A tuple, and then we have to check if it
482 * resolves some other pair. Hence, we need a loop here.
483 */
484 old_tid = old_tuple->t_self;
485 free_new = false;
486
487 for (;;)
488 {
489 ItemPointerData new_tid;
490
491 /* Insert the tuple and find out where it's put in new_heap */
492 raw_heap_insert(state, new_tuple);
493 new_tid = new_tuple->t_self;
494
495 logical_rewrite_heap_tuple(state, old_tid, new_tuple);
496
497 /*
498 * If the tuple is the updated version of a row, and the prior version
499 * wouldn't be DEAD yet, then we need to either resolve the prior
500 * version (if it's waiting in rs_unresolved_tups), or make an entry
501 * in rs_old_new_tid_map (so we can resolve it when we do see it). The
502 * previous tuple's xmax would equal this one's xmin, so it's
503 * RECENTLY_DEAD if and only if the xmin is not before OldestXmin.
504 */
505 if ((new_tuple->t_data->t_infomask & HEAP_UPDATED) &&
506 !TransactionIdPrecedes(HeapTupleHeaderGetXmin(new_tuple->t_data),
507 state->rs_oldest_xmin))
508 {
509 /*
510 * Okay, this is B in an update pair. See if we've seen A.
511 */
512 UnresolvedTup unresolved;
513
514 memset(&hashkey, 0, sizeof(hashkey));
515 hashkey.xmin = HeapTupleHeaderGetXmin(new_tuple->t_data);
516 hashkey.tid = old_tid;
517
518 unresolved = hash_search(state->rs_unresolved_tups, &hashkey,
519 HASH_FIND, NULL);
520
521 if (unresolved != NULL)
522 {
523 /*
524 * We have seen and memorized the previous tuple already. Now
525 * that we know where we inserted the tuple its t_ctid points
526 * to, fix its t_ctid and insert it to the new heap.
527 */
528 if (free_new)
529 heap_freetuple(new_tuple);
530 new_tuple = unresolved->tuple;
531 free_new = true;
532 old_tid = unresolved->old_tid;
533 new_tuple->t_data->t_ctid = new_tid;
534
535 /*
536 * We don't need the hash entry anymore, but don't free its
537 * tuple just yet.
538 */
539 hash_search(state->rs_unresolved_tups, &hashkey,
540 HASH_REMOVE, &found);
541 Assert(found);
542
543 /* loop back to insert the previous tuple in the chain */
544 continue;
545 }
546 else
547 {
548 /*
549 * Remember the new tid of this tuple. We'll use it to set the
550 * ctid when we find the previous tuple in the chain.
551 */
552 OldToNewMapping mapping;
553
554 mapping = hash_search(state->rs_old_new_tid_map, &hashkey,
555 HASH_ENTER, &found);
556 Assert(!found);
557
558 mapping->new_tid = new_tid;
559 }
560 }
561
562 /* Done with this (chain of) tuples, for now */
563 if (free_new)
564 heap_freetuple(new_tuple);
565 break;
566 }
567
568 MemoryContextSwitchTo(old_cxt);
569}
570
571/*
572 * Register a dead tuple with an ongoing rewrite. Dead tuples are not
573 * copied to the new table, but we still make note of them so that we
574 * can release some resources earlier.
575 *
576 * Returns true if a tuple was removed from the unresolved_tups table.
577 * This indicates that that tuple, previously thought to be "recently dead",
578 * is now known really dead and won't be written to the output.
579 */
580bool
581rewrite_heap_dead_tuple(RewriteState state, HeapTuple old_tuple)
582{
583 /*
584 * If we have already seen an earlier tuple in the update chain that
585 * points to this tuple, let's forget about that earlier tuple. It's in
586 * fact dead as well, our simple xmax < OldestXmin test in
587 * HeapTupleSatisfiesVacuum just wasn't enough to detect it. It happens
588 * when xmin of a tuple is greater than xmax, which sounds
589 * counter-intuitive but is perfectly valid.
590 *
591 * We don't bother to try to detect the situation the other way round,
592 * when we encounter the dead tuple first and then the recently dead one
593 * that points to it. If that happens, we'll have some unmatched entries
594 * in the UnresolvedTups hash table at the end. That can happen anyway,
595 * because a vacuum might have removed the dead tuple in the chain before
596 * us.
597 */
598 UnresolvedTup unresolved;
599 TidHashKey hashkey;
600 bool found;
601
602 memset(&hashkey, 0, sizeof(hashkey));
603 hashkey.xmin = HeapTupleHeaderGetXmin(old_tuple->t_data);
604 hashkey.tid = old_tuple->t_self;
605
606 unresolved = hash_search(state->rs_unresolved_tups, &hashkey,
607 HASH_FIND, NULL);
608
609 if (unresolved != NULL)
610 {
611 /* Need to free the contained tuple as well as the hashtable entry */
612 heap_freetuple(unresolved->tuple);
613 hash_search(state->rs_unresolved_tups, &hashkey,
614 HASH_REMOVE, &found);
615 Assert(found);
616 return true;
617 }
618
619 return false;
620}
621
622/*
623 * Insert a tuple to the new relation. This has to track heap_insert
624 * and its subsidiary functions!
625 *
626 * t_self of the tuple is set to the new TID of the tuple. If t_ctid of the
627 * tuple is invalid on entry, it's replaced with the new TID as well (in
628 * the inserted data only, not in the caller's copy).
629 */
630static void
631raw_heap_insert(RewriteState state, HeapTuple tup)
632{
633 Page page = state->rs_buffer;
634 Size pageFreeSpace,
635 saveFreeSpace;
636 Size len;
637 OffsetNumber newoff;
638 HeapTuple heaptup;
639
640 /*
641 * If the new tuple is too big for storage or contains already toasted
642 * out-of-line attributes from some other relation, invoke the toaster.
643 *
644 * Note: below this point, heaptup is the data we actually intend to store
645 * into the relation; tup is the caller's original untoasted data.
646 */
647 if (state->rs_new_rel->rd_rel->relkind == RELKIND_TOASTVALUE)
648 {
649 /* toast table entries should never be recursively toasted */
650 Assert(!HeapTupleHasExternal(tup));
651 heaptup = tup;
652 }
653 else if (HeapTupleHasExternal(tup) || tup->t_len > TOAST_TUPLE_THRESHOLD)
654 {
655 int options = HEAP_INSERT_SKIP_FSM;
656
657 if (!state->rs_use_wal)
658 options |= HEAP_INSERT_SKIP_WAL;
659
660 /*
661 * While rewriting the heap for VACUUM FULL / CLUSTER, make sure data
662 * for the TOAST table are not logically decoded. The main heap is
663 * WAL-logged as XLOG FPI records, which are not logically decoded.
664 */
665 options |= HEAP_INSERT_NO_LOGICAL;
666
667 heaptup = toast_insert_or_update(state->rs_new_rel, tup, NULL,
668 options);
669 }
670 else
671 heaptup = tup;
672
673 len = MAXALIGN(heaptup->t_len); /* be conservative */
674
675 /*
676 * If we're gonna fail for oversize tuple, do it right away
677 */
678 if (len > MaxHeapTupleSize)
679 ereport(ERROR,
680 (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
681 errmsg("row is too big: size %zu, maximum size %zu",
682 len, MaxHeapTupleSize)));
683
684 /* Compute desired extra freespace due to fillfactor option */
685 saveFreeSpace = RelationGetTargetPageFreeSpace(state->rs_new_rel,
686 HEAP_DEFAULT_FILLFACTOR);
687
688 /* Now we can check to see if there's enough free space already. */
689 if (state->rs_buffer_valid)
690 {
691 pageFreeSpace = PageGetHeapFreeSpace(page);
692
693 if (len + saveFreeSpace > pageFreeSpace)
694 {
695 /* Doesn't fit, so write out the existing page */
696
697 /* XLOG stuff */
698 if (state->rs_use_wal)
699 log_newpage(&state->rs_new_rel->rd_node,
700 MAIN_FORKNUM,
701 state->rs_blockno,
702 page,
703 true);
704
705 /*
706 * Now write the page. We say isTemp = true even if it's not a
707 * temp table, because there's no need for smgr to schedule an
708 * fsync for this write; we'll do it ourselves in
709 * end_heap_rewrite.
710 */
711 RelationOpenSmgr(state->rs_new_rel);
712
713 PageSetChecksumInplace(page, state->rs_blockno);
714
715 smgrextend(state->rs_new_rel->rd_smgr, MAIN_FORKNUM,
716 state->rs_blockno, (char *) page, true);
717
718 state->rs_blockno++;
719 state->rs_buffer_valid = false;
720 }
721 }
722
723 if (!state->rs_buffer_valid)
724 {
725 /* Initialize a new empty page */
726 PageInit(page, BLCKSZ, 0);
727 state->rs_buffer_valid = true;
728 }
729
730 /* And now we can insert the tuple into the page */
731 newoff = PageAddItem(page, (Item) heaptup->t_data, heaptup->t_len,
732 InvalidOffsetNumber, false, true);
733 if (newoff == InvalidOffsetNumber)
734 elog(ERROR, "failed to add tuple");
735
736 /* Update caller's t_self to the actual position where it was stored */
737 ItemPointerSet(&(tup->t_self), state->rs_blockno, newoff);
738
739 /*
740 * Insert the correct position into CTID of the stored tuple, too, if the
741 * caller didn't supply a valid CTID.
742 */
743 if (!ItemPointerIsValid(&tup->t_data->t_ctid))
744 {
745 ItemId newitemid;
746 HeapTupleHeader onpage_tup;
747
748 newitemid = PageGetItemId(page, newoff);
749 onpage_tup = (HeapTupleHeader) PageGetItem(page, newitemid);
750
751 onpage_tup->t_ctid = tup->t_self;
752 }
753
754 /* If heaptup is a private copy, release it. */
755 if (heaptup != tup)
756 heap_freetuple(heaptup);
757}
758
759/* ------------------------------------------------------------------------
760 * Logical rewrite support
761 *
762 * When doing logical decoding - which relies on using cmin/cmax of catalog
763 * tuples, via xl_heap_new_cid records - heap rewrites have to log enough
764 * information to allow the decoding backend to updates its internal mapping
765 * of (relfilenode,ctid) => (cmin, cmax) to be correct for the rewritten heap.
766 *
767 * For that, every time we find a tuple that's been modified in a catalog
768 * relation within the xmin horizon of any decoding slot, we log a mapping
769 * from the old to the new location.
770 *
771 * To deal with rewrites that abort the filename of a mapping file contains
772 * the xid of the transaction performing the rewrite, which then can be
773 * checked before being read in.
774 *
775 * For efficiency we don't immediately spill every single map mapping for a
776 * row to disk but only do so in batches when we've collected several of them
777 * in memory or when end_heap_rewrite() has been called.
778 *
779 * Crash-Safety: This module diverts from the usual patterns of doing WAL
780 * since it cannot rely on checkpoint flushing out all buffers and thus
781 * waiting for exclusive locks on buffers. Usually the XLogInsert() covering
782 * buffer modifications is performed while the buffer(s) that are being
783 * modified are exclusively locked guaranteeing that both the WAL record and
784 * the modified heap are on either side of the checkpoint. But since the
785 * mapping files we log aren't in shared_buffers that interlock doesn't work.
786 *
787 * Instead we simply write the mapping files out to disk, *before* the
788 * XLogInsert() is performed. That guarantees that either the XLogInsert() is
789 * inserted after the checkpoint's redo pointer or that the checkpoint (via
790 * LogicalRewriteHeapCheckpoint()) has flushed the (partial) mapping file to
791 * disk. That leaves the tail end that has not yet been flushed open to
792 * corruption, which is solved by including the current offset in the
793 * xl_heap_rewrite_mapping records and truncating the mapping file to it
794 * during replay. Every time a rewrite is finished all generated mapping files
795 * are synced to disk.
796 *
797 * Note that if we were only concerned about crash safety we wouldn't have to
798 * deal with WAL logging at all - an fsync() at the end of a rewrite would be
799 * sufficient for crash safety. Any mapping that hasn't been safely flushed to
800 * disk has to be by an aborted (explicitly or via a crash) transaction and is
801 * ignored by virtue of the xid in its name being subject to a
802 * TransactionDidCommit() check. But we want to support having standbys via
803 * physical replication, both for availability and to do logical decoding
804 * there.
805 * ------------------------------------------------------------------------
806 */
807
808/*
809 * Do preparations for logging logical mappings during a rewrite if
810 * necessary. If we detect that we don't need to log anything we'll prevent
811 * any further action by the various logical rewrite functions.
812 */
813static void
814logical_begin_heap_rewrite(RewriteState state)
815{
816 HASHCTL hash_ctl;
817 TransactionId logical_xmin;
818
819 /*
820 * We only need to persist these mappings if the rewritten table can be
821 * accessed during logical decoding, if not, we can skip doing any
822 * additional work.
823 */
824 state->rs_logical_rewrite =
825 RelationIsAccessibleInLogicalDecoding(state->rs_old_rel);
826
827 if (!state->rs_logical_rewrite)
828 return;
829
830 ProcArrayGetReplicationSlotXmin(NULL, &logical_xmin);
831
832 /*
833 * If there are no logical slots in progress we don't need to do anything,
834 * there cannot be any remappings for relevant rows yet. The relation's
835 * lock protects us against races.
836 */
837 if (logical_xmin == InvalidTransactionId)
838 {
839 state->rs_logical_rewrite = false;
840 return;
841 }
842
843 state->rs_logical_xmin = logical_xmin;
844 state->rs_begin_lsn = GetXLogInsertRecPtr();
845 state->rs_num_rewrite_mappings = 0;
846
847 memset(&hash_ctl, 0, sizeof(hash_ctl));
848 hash_ctl.keysize = sizeof(TransactionId);
849 hash_ctl.entrysize = sizeof(RewriteMappingFile);
850 hash_ctl.hcxt = state->rs_cxt;
851
852 state->rs_logical_mappings =
853 hash_create("Logical rewrite mapping",
854 128, /* arbitrary initial size */
855 &hash_ctl,
856 HASH_ELEM | HASH_BLOBS | HASH_CONTEXT);
857}
858
859/*
860 * Flush all logical in-memory mappings to disk, but don't fsync them yet.
861 */
862static void
863logical_heap_rewrite_flush_mappings(RewriteState state)
864{
865 HASH_SEQ_STATUS seq_status;
866 RewriteMappingFile *src;
867 dlist_mutable_iter iter;
868
869 Assert(state->rs_logical_rewrite);
870
871 /* no logical rewrite in progress, no need to iterate over mappings */
872 if (state->rs_num_rewrite_mappings == 0)
873 return;
874
875 elog(DEBUG1, "flushing %u logical rewrite mapping entries",
876 state->rs_num_rewrite_mappings);
877
878 hash_seq_init(&seq_status, state->rs_logical_mappings);
879 while ((src = (RewriteMappingFile *) hash_seq_search(&seq_status)) != NULL)
880 {
881 char *waldata;
882 char *waldata_start;
883 xl_heap_rewrite_mapping xlrec;
884 Oid dboid;
885 uint32 len;
886 int written;
887
888 /* this file hasn't got any new mappings */
889 if (src->num_mappings == 0)
890 continue;
891
892 if (state->rs_old_rel->rd_rel->relisshared)
893 dboid = InvalidOid;
894 else
895 dboid = MyDatabaseId;
896
897 xlrec.num_mappings = src->num_mappings;
898 xlrec.mapped_rel = RelationGetRelid(state->rs_old_rel);
899 xlrec.mapped_xid = src->xid;
900 xlrec.mapped_db = dboid;
901 xlrec.offset = src->off;
902 xlrec.start_lsn = state->rs_begin_lsn;
903
904 /* write all mappings consecutively */
905 len = src->num_mappings * sizeof(LogicalRewriteMappingData);
906 waldata_start = waldata = palloc(len);
907
908 /*
909 * collect data we need to write out, but don't modify ondisk data yet
910 */
911 dlist_foreach_modify(iter, &src->mappings)
912 {
913 RewriteMappingDataEntry *pmap;
914
915 pmap = dlist_container(RewriteMappingDataEntry, node, iter.cur);
916
917 memcpy(waldata, &pmap->map, sizeof(pmap->map));
918 waldata += sizeof(pmap->map);
919
920 /* remove from the list and free */
921 dlist_delete(&pmap->node);
922 pfree(pmap);
923
924 /* update bookkeeping */
925 state->rs_num_rewrite_mappings--;
926 src->num_mappings--;
927 }
928
929 Assert(src->num_mappings == 0);
930 Assert(waldata == waldata_start + len);
931
932 /*
933 * Note that we deviate from the usual WAL coding practices here,
934 * check the above "Logical rewrite support" comment for reasoning.
935 */
936 written = FileWrite(src->vfd, waldata_start, len, src->off,
937 WAIT_EVENT_LOGICAL_REWRITE_WRITE);
938 if (written != len)
939 ereport(ERROR,
940 (errcode_for_file_access(),
941 errmsg("could not write to file \"%s\", wrote %d of %d: %m", src->path,
942 written, len)));
943 src->off += len;
944
945 XLogBeginInsert();
946 XLogRegisterData((char *) (&xlrec), sizeof(xlrec));
947 XLogRegisterData(waldata_start, len);
948
949 /* write xlog record */
950 XLogInsert(RM_HEAP2_ID, XLOG_HEAP2_REWRITE);
951
952 pfree(waldata_start);
953 }
954 Assert(state->rs_num_rewrite_mappings == 0);
955}
956
957/*
958 * Logical remapping part of end_heap_rewrite().
959 */
960static void
961logical_end_heap_rewrite(RewriteState state)
962{
963 HASH_SEQ_STATUS seq_status;
964 RewriteMappingFile *src;
965
966 /* done, no logical rewrite in progress */
967 if (!state->rs_logical_rewrite)
968 return;
969
970 /* writeout remaining in-memory entries */
971 if (state->rs_num_rewrite_mappings > 0)
972 logical_heap_rewrite_flush_mappings(state);
973
974 /* Iterate over all mappings we have written and fsync the files. */
975 hash_seq_init(&seq_status, state->rs_logical_mappings);
976 while ((src = (RewriteMappingFile *) hash_seq_search(&seq_status)) != NULL)
977 {
978 if (FileSync(src->vfd, WAIT_EVENT_LOGICAL_REWRITE_SYNC) != 0)
979 ereport(data_sync_elevel(ERROR),
980 (errcode_for_file_access(),
981 errmsg("could not fsync file \"%s\": %m", src->path)));
982 FileClose(src->vfd);
983 }
984 /* memory context cleanup will deal with the rest */
985}
986
987/*
988 * Log a single (old->new) mapping for 'xid'.
989 */
990static void
991logical_rewrite_log_mapping(RewriteState state, TransactionId xid,
992 LogicalRewriteMappingData *map)
993{
994 RewriteMappingFile *src;
995 RewriteMappingDataEntry *pmap;
996 Oid relid;
997 bool found;
998
999 relid = RelationGetRelid(state->rs_old_rel);
1000
1001 /* look for existing mappings for this 'mapped' xid */
1002 src = hash_search(state->rs_logical_mappings, &xid,
1003 HASH_ENTER, &found);
1004
1005 /*
1006 * We haven't yet had the need to map anything for this xid, create
1007 * per-xid data structures.
1008 */
1009 if (!found)
1010 {
1011 char path[MAXPGPATH];
1012 Oid dboid;
1013
1014 if (state->rs_old_rel->rd_rel->relisshared)
1015 dboid = InvalidOid;
1016 else
1017 dboid = MyDatabaseId;
1018
1019 snprintf(path, MAXPGPATH,
1020 "pg_logical/mappings/" LOGICAL_REWRITE_FORMAT,
1021 dboid, relid,
1022 (uint32) (state->rs_begin_lsn >> 32),
1023 (uint32) state->rs_begin_lsn,
1024 xid, GetCurrentTransactionId());
1025
1026 dlist_init(&src->mappings);
1027 src->num_mappings = 0;
1028 src->off = 0;
1029 memcpy(src->path, path, sizeof(path));
1030 src->vfd = PathNameOpenFile(path,
1031 O_CREAT | O_EXCL | O_WRONLY | PG_BINARY);
1032 if (src->vfd < 0)
1033 ereport(ERROR,
1034 (errcode_for_file_access(),
1035 errmsg("could not create file \"%s\": %m", path)));
1036 }
1037
1038 pmap = MemoryContextAlloc(state->rs_cxt,
1039 sizeof(RewriteMappingDataEntry));
1040 memcpy(&pmap->map, map, sizeof(LogicalRewriteMappingData));
1041 dlist_push_tail(&src->mappings, &pmap->node);
1042 src->num_mappings++;
1043 state->rs_num_rewrite_mappings++;
1044
1045 /*
1046 * Write out buffer every time we've too many in-memory entries across all
1047 * mapping files.
1048 */
1049 if (state->rs_num_rewrite_mappings >= 1000 /* arbitrary number */ )
1050 logical_heap_rewrite_flush_mappings(state);
1051}
1052
1053/*
1054 * Perform logical remapping for a tuple that's mapped from old_tid to
1055 * new_tuple->t_self by rewrite_heap_tuple() if necessary for the tuple.
1056 */
1057static void
1058logical_rewrite_heap_tuple(RewriteState state, ItemPointerData old_tid,
1059 HeapTuple new_tuple)
1060{
1061 ItemPointerData new_tid = new_tuple->t_self;
1062 TransactionId cutoff = state->rs_logical_xmin;
1063 TransactionId xmin;
1064 TransactionId xmax;
1065 bool do_log_xmin = false;
1066 bool do_log_xmax = false;
1067 LogicalRewriteMappingData map;
1068
1069 /* no logical rewrite in progress, we don't need to log anything */
1070 if (!state->rs_logical_rewrite)
1071 return;
1072
1073 xmin = HeapTupleHeaderGetXmin(new_tuple->t_data);
1074 /* use *GetUpdateXid to correctly deal with multixacts */
1075 xmax = HeapTupleHeaderGetUpdateXid(new_tuple->t_data);
1076
1077 /*
1078 * Log the mapping iff the tuple has been created recently.
1079 */
1080 if (TransactionIdIsNormal(xmin) && !TransactionIdPrecedes(xmin, cutoff))
1081 do_log_xmin = true;
1082
1083 if (!TransactionIdIsNormal(xmax))
1084 {
1085 /*
1086 * no xmax is set, can't have any permanent ones, so this check is
1087 * sufficient
1088 */
1089 }
1090 else if (HEAP_XMAX_IS_LOCKED_ONLY(new_tuple->t_data->t_infomask))
1091 {
1092 /* only locked, we don't care */
1093 }
1094 else if (!TransactionIdPrecedes(xmax, cutoff))
1095 {
1096 /* tuple has been deleted recently, log */
1097 do_log_xmax = true;
1098 }
1099
1100 /* if neither needs to be logged, we're done */
1101 if (!do_log_xmin && !do_log_xmax)
1102 return;
1103
1104 /* fill out mapping information */
1105 map.old_node = state->rs_old_rel->rd_node;
1106 map.old_tid = old_tid;
1107 map.new_node = state->rs_new_rel->rd_node;
1108 map.new_tid = new_tid;
1109
1110 /* ---
1111 * Now persist the mapping for the individual xids that are affected. We
1112 * need to log for both xmin and xmax if they aren't the same transaction
1113 * since the mapping files are per "affected" xid.
1114 * We don't muster all that much effort detecting whether xmin and xmax
1115 * are actually the same transaction, we just check whether the xid is the
1116 * same disregarding subtransactions. Logging too much is relatively
1117 * harmless and we could never do the check fully since subtransaction
1118 * data is thrown away during restarts.
1119 * ---
1120 */
1121 if (do_log_xmin)
1122 logical_rewrite_log_mapping(state, xmin, &map);
1123 /* separately log mapping for xmax unless it'd be redundant */
1124 if (do_log_xmax && !TransactionIdEquals(xmin, xmax))
1125 logical_rewrite_log_mapping(state, xmax, &map);
1126}
1127
1128/*
1129 * Replay XLOG_HEAP2_REWRITE records
1130 */
1131void
1132heap_xlog_logical_rewrite(XLogReaderState *r)
1133{
1134 char path[MAXPGPATH];
1135 int fd;
1136 xl_heap_rewrite_mapping *xlrec;
1137 uint32 len;
1138 char *data;
1139
1140 xlrec = (xl_heap_rewrite_mapping *) XLogRecGetData(r);
1141
1142 snprintf(path, MAXPGPATH,
1143 "pg_logical/mappings/" LOGICAL_REWRITE_FORMAT,
1144 xlrec->mapped_db, xlrec->mapped_rel,
1145 (uint32) (xlrec->start_lsn >> 32),
1146 (uint32) xlrec->start_lsn,
1147 xlrec->mapped_xid, XLogRecGetXid(r));
1148
1149 fd = OpenTransientFile(path,
1150 O_CREAT | O_WRONLY | PG_BINARY);
1151 if (fd < 0)
1152 ereport(ERROR,
1153 (errcode_for_file_access(),
1154 errmsg("could not create file \"%s\": %m", path)));
1155
1156 /*
1157 * Truncate all data that's not guaranteed to have been safely fsynced (by
1158 * previous record or by the last checkpoint).
1159 */
1160 pgstat_report_wait_start(WAIT_EVENT_LOGICAL_REWRITE_TRUNCATE);
1161 if (ftruncate(fd, xlrec->offset) != 0)
1162 ereport(ERROR,
1163 (errcode_for_file_access(),
1164 errmsg("could not truncate file \"%s\" to %u: %m",
1165 path, (uint32) xlrec->offset)));
1166 pgstat_report_wait_end();
1167
1168 /* now seek to the position we want to write our data to */
1169 if (lseek(fd, xlrec->offset, SEEK_SET) != xlrec->offset)
1170 ereport(ERROR,
1171 (errcode_for_file_access(),
1172 errmsg("could not seek to end of file \"%s\": %m",
1173 path)));
1174
1175 data = XLogRecGetData(r) + sizeof(*xlrec);
1176
1177 len = xlrec->num_mappings * sizeof(LogicalRewriteMappingData);
1178
1179 /* write out tail end of mapping file (again) */
1180 errno = 0;
1181 pgstat_report_wait_start(WAIT_EVENT_LOGICAL_REWRITE_MAPPING_WRITE);
1182 if (write(fd, data, len) != len)
1183 {
1184 /* if write didn't set errno, assume problem is no disk space */
1185 if (errno == 0)
1186 errno = ENOSPC;
1187 ereport(ERROR,
1188 (errcode_for_file_access(),
1189 errmsg("could not write to file \"%s\": %m", path)));
1190 }
1191 pgstat_report_wait_end();
1192
1193 /*
1194 * Now fsync all previously written data. We could improve things and only
1195 * do this for the last write to a file, but the required bookkeeping
1196 * doesn't seem worth the trouble.
1197 */
1198 pgstat_report_wait_start(WAIT_EVENT_LOGICAL_REWRITE_MAPPING_SYNC);
1199 if (pg_fsync(fd) != 0)
1200 ereport(data_sync_elevel(ERROR),
1201 (errcode_for_file_access(),
1202 errmsg("could not fsync file \"%s\": %m", path)));
1203 pgstat_report_wait_end();
1204
1205 if (CloseTransientFile(fd))
1206 ereport(ERROR,
1207 (errcode_for_file_access(),
1208 errmsg("could not close file \"%s\": %m", path)));
1209}
1210
1211/* ---
1212 * Perform a checkpoint for logical rewrite mappings
1213 *
1214 * This serves two tasks:
1215 * 1) Remove all mappings not needed anymore based on the logical restart LSN
1216 * 2) Flush all remaining mappings to disk, so that replay after a checkpoint
1217 * only has to deal with the parts of a mapping that have been written out
1218 * after the checkpoint started.
1219 * ---
1220 */
1221void
1222CheckPointLogicalRewriteHeap(void)
1223{
1224 XLogRecPtr cutoff;
1225 XLogRecPtr redo;
1226 DIR *mappings_dir;
1227 struct dirent *mapping_de;
1228 char path[MAXPGPATH + 20];
1229
1230 /*
1231 * We start of with a minimum of the last redo pointer. No new decoding
1232 * slot will start before that, so that's a safe upper bound for removal.
1233 */
1234 redo = GetRedoRecPtr();
1235
1236 /* now check for the restart ptrs from existing slots */
1237 cutoff = ReplicationSlotsComputeLogicalRestartLSN();
1238
1239 /* don't start earlier than the restart lsn */
1240 if (cutoff != InvalidXLogRecPtr && redo < cutoff)
1241 cutoff = redo;
1242
1243 mappings_dir = AllocateDir("pg_logical/mappings");
1244 while ((mapping_de = ReadDir(mappings_dir, "pg_logical/mappings")) != NULL)
1245 {
1246 struct stat statbuf;
1247 Oid dboid;
1248 Oid relid;
1249 XLogRecPtr lsn;
1250 TransactionId rewrite_xid;
1251 TransactionId create_xid;
1252 uint32 hi,
1253 lo;
1254
1255 if (strcmp(mapping_de->d_name, ".") == 0 ||
1256 strcmp(mapping_de->d_name, "..") == 0)
1257 continue;
1258
1259 snprintf(path, sizeof(path), "pg_logical/mappings/%s", mapping_de->d_name);
1260 if (lstat(path, &statbuf) == 0 && !S_ISREG(statbuf.st_mode))
1261 continue;
1262
1263 /* Skip over files that cannot be ours. */
1264 if (strncmp(mapping_de->d_name, "map-", 4) != 0)
1265 continue;
1266
1267 if (sscanf(mapping_de->d_name, LOGICAL_REWRITE_FORMAT,
1268 &dboid, &relid, &hi, &lo, &rewrite_xid, &create_xid) != 6)
1269 elog(ERROR, "could not parse filename \"%s\"", mapping_de->d_name);
1270
1271 lsn = ((uint64) hi) << 32 | lo;
1272
1273 if (lsn < cutoff || cutoff == InvalidXLogRecPtr)
1274 {
1275 elog(DEBUG1, "removing logical rewrite file \"%s\"", path);
1276 if (unlink(path) < 0)
1277 ereport(ERROR,
1278 (errcode_for_file_access(),
1279 errmsg("could not remove file \"%s\": %m", path)));
1280 }
1281 else
1282 {
1283 int fd = OpenTransientFile(path, O_RDONLY | PG_BINARY);
1284
1285 /*
1286 * The file cannot vanish due to concurrency since this function
1287 * is the only one removing logical mappings and it's run while
1288 * CheckpointLock is held exclusively.
1289 */
1290 if (fd < 0)
1291 ereport(ERROR,
1292 (errcode_for_file_access(),
1293 errmsg("could not open file \"%s\": %m", path)));
1294
1295 /*
1296 * We could try to avoid fsyncing files that either haven't
1297 * changed or have only been created since the checkpoint's start,
1298 * but it's currently not deemed worth the effort.
1299 */
1300 pgstat_report_wait_start(WAIT_EVENT_LOGICAL_REWRITE_CHECKPOINT_SYNC);
1301 if (pg_fsync(fd) != 0)
1302 ereport(data_sync_elevel(ERROR),
1303 (errcode_for_file_access(),
1304 errmsg("could not fsync file \"%s\": %m", path)));
1305 pgstat_report_wait_end();
1306
1307 if (CloseTransientFile(fd))
1308 ereport(ERROR,
1309 (errcode_for_file_access(),
1310 errmsg("could not close file \"%s\": %m", path)));
1311 }
1312 }
1313 FreeDir(mappings_dir);
1314}
1315