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visibilitymap.c
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1 /*-------------------------------------------------------------------------
2  *
3  * visibilitymap.c
4  * bitmap for tracking visibility of heap tuples
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/access/heap/visibilitymap.c
12  *
13  * INTERFACE ROUTINES
14  * visibilitymap_clear - clear bits for one page in the visibility map
15  * visibilitymap_pin - pin a map page for setting a bit
16  * visibilitymap_pin_ok - check whether correct map page is already pinned
17  * visibilitymap_set - set a bit in a previously pinned page
18  * visibilitymap_get_status - get status of bits
19  * visibilitymap_count - count number of bits set in visibility map
20  * visibilitymap_truncate - truncate the visibility map
21  *
22  * NOTES
23  *
24  * The visibility map is a bitmap with two bits (all-visible and all-frozen)
25  * per heap page. A set all-visible bit means that all tuples on the page are
26  * known visible to all transactions, and therefore the page doesn't need to
27  * be vacuumed. A set all-frozen bit means that all tuples on the page are
28  * completely frozen, and therefore the page doesn't need to be vacuumed even
29  * if whole table scanning vacuum is required (e.g. anti-wraparound vacuum).
30  * The all-frozen bit must be set only when the page is already all-visible.
31  *
32  * The map is conservative in the sense that we make sure that whenever a bit
33  * is set, we know the condition is true, but if a bit is not set, it might or
34  * might not be true.
35  *
36  * Clearing visibility map bits is not separately WAL-logged. The callers
37  * must make sure that whenever a bit is cleared, the bit is cleared on WAL
38  * replay of the updating operation as well.
39  *
40  * When we *set* a visibility map during VACUUM, we must write WAL. This may
41  * seem counterintuitive, since the bit is basically a hint: if it is clear,
42  * it may still be the case that every tuple on the page is visible to all
43  * transactions; we just don't know that for certain. The difficulty is that
44  * there are two bits which are typically set together: the PD_ALL_VISIBLE bit
45  * on the page itself, and the visibility map bit. If a crash occurs after the
46  * visibility map page makes it to disk and before the updated heap page makes
47  * it to disk, redo must set the bit on the heap page. Otherwise, the next
48  * insert, update, or delete on the heap page will fail to realize that the
49  * visibility map bit must be cleared, possibly causing index-only scans to
50  * return wrong answers.
51  *
52  * VACUUM will normally skip pages for which the visibility map bit is set;
53  * such pages can't contain any dead tuples and therefore don't need vacuuming.
54  *
55  * LOCKING
56  *
57  * In heapam.c, whenever a page is modified so that not all tuples on the
58  * page are visible to everyone anymore, the corresponding bit in the
59  * visibility map is cleared. In order to be crash-safe, we need to do this
60  * while still holding a lock on the heap page and in the same critical
61  * section that logs the page modification. However, we don't want to hold
62  * the buffer lock over any I/O that may be required to read in the visibility
63  * map page. To avoid this, we examine the heap page before locking it;
64  * if the page-level PD_ALL_VISIBLE bit is set, we pin the visibility map
65  * bit. Then, we lock the buffer. But this creates a race condition: there
66  * is a possibility that in the time it takes to lock the buffer, the
67  * PD_ALL_VISIBLE bit gets set. If that happens, we have to unlock the
68  * buffer, pin the visibility map page, and relock the buffer. This shouldn't
69  * happen often, because only VACUUM currently sets visibility map bits,
70  * and the race will only occur if VACUUM processes a given page at almost
71  * exactly the same time that someone tries to further modify it.
72  *
73  * To set a bit, you need to hold a lock on the heap page. That prevents
74  * the race condition where VACUUM sees that all tuples on the page are
75  * visible to everyone, but another backend modifies the page before VACUUM
76  * sets the bit in the visibility map.
77  *
78  * When a bit is set, the LSN of the visibility map page is updated to make
79  * sure that the visibility map update doesn't get written to disk before the
80  * WAL record of the changes that made it possible to set the bit is flushed.
81  * But when a bit is cleared, we don't have to do that because it's always
82  * safe to clear a bit in the map from correctness point of view.
83  *
84  *-------------------------------------------------------------------------
85  */
86 #include "postgres.h"
87 
88 #include "access/heapam_xlog.h"
89 #include "access/visibilitymap.h"
90 #include "access/xlog.h"
91 #include "miscadmin.h"
92 #include "port/pg_bitutils.h"
93 #include "storage/bufmgr.h"
94 #include "storage/lmgr.h"
95 #include "storage/smgr.h"
96 #include "utils/inval.h"
97 
98 
99 /*#define TRACE_VISIBILITYMAP */
100 
101 /*
102  * Size of the bitmap on each visibility map page, in bytes. There's no
103  * extra headers, so the whole page minus the standard page header is
104  * used for the bitmap.
105  */
106 #define MAPSIZE (BLCKSZ - MAXALIGN(SizeOfPageHeaderData))
107 
108 /* Number of heap blocks we can represent in one byte */
109 #define HEAPBLOCKS_PER_BYTE (BITS_PER_BYTE / BITS_PER_HEAPBLOCK)
110 
111 /* Number of heap blocks we can represent in one visibility map page. */
112 #define HEAPBLOCKS_PER_PAGE (MAPSIZE * HEAPBLOCKS_PER_BYTE)
113 
114 /* Mapping from heap block number to the right bit in the visibility map */
115 #define HEAPBLK_TO_MAPBLOCK(x) ((x) / HEAPBLOCKS_PER_PAGE)
116 #define HEAPBLK_TO_MAPBYTE(x) (((x) % HEAPBLOCKS_PER_PAGE) / HEAPBLOCKS_PER_BYTE)
117 #define HEAPBLK_TO_OFFSET(x) (((x) % HEAPBLOCKS_PER_BYTE) * BITS_PER_HEAPBLOCK)
118 
119 /* Masks for counting subsets of bits in the visibility map. */
120 #define VISIBLE_MASK64 UINT64CONST(0x5555555555555555) /* The lower bit of each
121  * bit pair */
122 #define FROZEN_MASK64 UINT64CONST(0xaaaaaaaaaaaaaaaa) /* The upper bit of each
123  * bit pair */
124 
125 /* prototypes for internal routines */
126 static Buffer vm_readbuf(Relation rel, BlockNumber blkno, bool extend);
127 static void vm_extend(Relation rel, BlockNumber vm_nblocks);
128 
129 
130 /*
131  * visibilitymap_clear - clear specified bits for one page in visibility map
132  *
133  * You must pass a buffer containing the correct map page to this function.
134  * Call visibilitymap_pin first to pin the right one. This function doesn't do
135  * any I/O. Returns true if any bits have been cleared and false otherwise.
136  */
137 bool
139 {
140  BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
141  int mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
142  int mapOffset = HEAPBLK_TO_OFFSET(heapBlk);
143  uint8 mask = flags << mapOffset;
144  char *map;
145  bool cleared = false;
146 
148 
149 #ifdef TRACE_VISIBILITYMAP
150  elog(DEBUG1, "vm_clear %s %d", RelationGetRelationName(rel), heapBlk);
151 #endif
152 
153  if (!BufferIsValid(buf) || BufferGetBlockNumber(buf) != mapBlock)
154  elog(ERROR, "wrong buffer passed to visibilitymap_clear");
155 
157  map = PageGetContents(BufferGetPage(buf));
158 
159  if (map[mapByte] & mask)
160  {
161  map[mapByte] &= ~mask;
162 
163  MarkBufferDirty(buf);
164  cleared = true;
165  }
166 
168 
169  return cleared;
170 }
171 
172 /*
173  * visibilitymap_pin - pin a map page for setting a bit
174  *
175  * Setting a bit in the visibility map is a two-phase operation. First, call
176  * visibilitymap_pin, to pin the visibility map page containing the bit for
177  * the heap page. Because that can require I/O to read the map page, you
178  * shouldn't hold a lock on the heap page while doing that. Then, call
179  * visibilitymap_set to actually set the bit.
180  *
181  * On entry, *buf should be InvalidBuffer or a valid buffer returned by
182  * an earlier call to visibilitymap_pin or visibilitymap_get_status on the same
183  * relation. On return, *buf is a valid buffer with the map page containing
184  * the bit for heapBlk.
185  *
186  * If the page doesn't exist in the map file yet, it is extended.
187  */
188 void
190 {
191  BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
192 
193  /* Reuse the old pinned buffer if possible */
194  if (BufferIsValid(*buf))
195  {
196  if (BufferGetBlockNumber(*buf) == mapBlock)
197  return;
198 
199  ReleaseBuffer(*buf);
200  }
201  *buf = vm_readbuf(rel, mapBlock, true);
202 }
203 
204 /*
205  * visibilitymap_pin_ok - do we already have the correct page pinned?
206  *
207  * On entry, buf should be InvalidBuffer or a valid buffer returned by
208  * an earlier call to visibilitymap_pin or visibilitymap_get_status on the same
209  * relation. The return value indicates whether the buffer covers the
210  * given heapBlk.
211  */
212 bool
214 {
215  BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
216 
217  return BufferIsValid(buf) && BufferGetBlockNumber(buf) == mapBlock;
218 }
219 
220 /*
221  * visibilitymap_set - set bit(s) on a previously pinned page
222  *
223  * recptr is the LSN of the XLOG record we're replaying, if we're in recovery,
224  * or InvalidXLogRecPtr in normal running. The page LSN is advanced to the
225  * one provided; in normal running, we generate a new XLOG record and set the
226  * page LSN to that value. cutoff_xid is the largest xmin on the page being
227  * marked all-visible; it is needed for Hot Standby, and can be
228  * InvalidTransactionId if the page contains no tuples. It can also be set
229  * to InvalidTransactionId when a page that is already all-visible is being
230  * marked all-frozen.
231  *
232  * Caller is expected to set the heap page's PD_ALL_VISIBLE bit before calling
233  * this function. Except in recovery, caller should also pass the heap
234  * buffer. When checksums are enabled and we're not in recovery, we must add
235  * the heap buffer to the WAL chain to protect it from being torn.
236  *
237  * You must pass a buffer containing the correct map page to this function.
238  * Call visibilitymap_pin first to pin the right one. This function doesn't do
239  * any I/O.
240  */
241 void
243  XLogRecPtr recptr, Buffer vmBuf, TransactionId cutoff_xid,
244  uint8 flags)
245 {
246  BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
247  uint32 mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
248  uint8 mapOffset = HEAPBLK_TO_OFFSET(heapBlk);
249  Page page;
250  uint8 *map;
251 
252 #ifdef TRACE_VISIBILITYMAP
253  elog(DEBUG1, "vm_set %s %d", RelationGetRelationName(rel), heapBlk);
254 #endif
255 
257  Assert(InRecovery || BufferIsValid(heapBuf));
259 
260  /* Check that we have the right heap page pinned, if present */
261  if (BufferIsValid(heapBuf) && BufferGetBlockNumber(heapBuf) != heapBlk)
262  elog(ERROR, "wrong heap buffer passed to visibilitymap_set");
263 
264  /* Check that we have the right VM page pinned */
265  if (!BufferIsValid(vmBuf) || BufferGetBlockNumber(vmBuf) != mapBlock)
266  elog(ERROR, "wrong VM buffer passed to visibilitymap_set");
267 
268  page = BufferGetPage(vmBuf);
269  map = (uint8 *) PageGetContents(page);
271 
272  if (flags != (map[mapByte] >> mapOffset & VISIBILITYMAP_VALID_BITS))
273  {
275 
276  map[mapByte] |= (flags << mapOffset);
277  MarkBufferDirty(vmBuf);
278 
279  if (RelationNeedsWAL(rel))
280  {
281  if (XLogRecPtrIsInvalid(recptr))
282  {
283  Assert(!InRecovery);
284  recptr = log_heap_visible(rel->rd_node, heapBuf, vmBuf,
285  cutoff_xid, flags);
286 
287  /*
288  * If data checksums are enabled (or wal_log_hints=on), we
289  * need to protect the heap page from being torn.
290  */
291  if (XLogHintBitIsNeeded())
292  {
293  Page heapPage = BufferGetPage(heapBuf);
294 
295  /* caller is expected to set PD_ALL_VISIBLE first */
296  Assert(PageIsAllVisible(heapPage));
297  PageSetLSN(heapPage, recptr);
298  }
299  }
300  PageSetLSN(page, recptr);
301  }
302 
304  }
305 
307 }
308 
309 /*
310  * visibilitymap_get_status - get status of bits
311  *
312  * Are all tuples on heapBlk visible to all or are marked frozen, according
313  * to the visibility map?
314  *
315  * On entry, *buf should be InvalidBuffer or a valid buffer returned by an
316  * earlier call to visibilitymap_pin or visibilitymap_get_status on the same
317  * relation. On return, *buf is a valid buffer with the map page containing
318  * the bit for heapBlk, or InvalidBuffer. The caller is responsible for
319  * releasing *buf after it's done testing and setting bits.
320  *
321  * NOTE: This function is typically called without a lock on the heap page,
322  * so somebody else could change the bit just after we look at it. In fact,
323  * since we don't lock the visibility map page either, it's even possible that
324  * someone else could have changed the bit just before we look at it, but yet
325  * we might see the old value. It is the caller's responsibility to deal with
326  * all concurrency issues!
327  */
328 uint8
330 {
331  BlockNumber mapBlock = HEAPBLK_TO_MAPBLOCK(heapBlk);
332  uint32 mapByte = HEAPBLK_TO_MAPBYTE(heapBlk);
333  uint8 mapOffset = HEAPBLK_TO_OFFSET(heapBlk);
334  char *map;
335  uint8 result;
336 
337 #ifdef TRACE_VISIBILITYMAP
338  elog(DEBUG1, "vm_get_status %s %d", RelationGetRelationName(rel), heapBlk);
339 #endif
340 
341  /* Reuse the old pinned buffer if possible */
342  if (BufferIsValid(*buf))
343  {
344  if (BufferGetBlockNumber(*buf) != mapBlock)
345  {
346  ReleaseBuffer(*buf);
347  *buf = InvalidBuffer;
348  }
349  }
350 
351  if (!BufferIsValid(*buf))
352  {
353  *buf = vm_readbuf(rel, mapBlock, false);
354  if (!BufferIsValid(*buf))
355  return false;
356  }
357 
358  map = PageGetContents(BufferGetPage(*buf));
359 
360  /*
361  * A single byte read is atomic. There could be memory-ordering effects
362  * here, but for performance reasons we make it the caller's job to worry
363  * about that.
364  */
365  result = ((map[mapByte] >> mapOffset) & VISIBILITYMAP_VALID_BITS);
366  return result;
367 }
368 
369 /*
370  * visibilitymap_count - count number of bits set in visibility map
371  *
372  * Note: we ignore the possibility of race conditions when the table is being
373  * extended concurrently with the call. New pages added to the table aren't
374  * going to be marked all-visible or all-frozen, so they won't affect the result.
375  */
376 void
377 visibilitymap_count(Relation rel, BlockNumber *all_visible, BlockNumber *all_frozen)
378 {
379  BlockNumber mapBlock;
380  BlockNumber nvisible = 0;
381  BlockNumber nfrozen = 0;
382 
383  /* all_visible must be specified */
384  Assert(all_visible);
385 
386  for (mapBlock = 0;; mapBlock++)
387  {
388  Buffer mapBuffer;
389  uint64 *map;
390  int i;
391 
392  /*
393  * Read till we fall off the end of the map. We assume that any extra
394  * bytes in the last page are zeroed, so we don't bother excluding
395  * them from the count.
396  */
397  mapBuffer = vm_readbuf(rel, mapBlock, false);
398  if (!BufferIsValid(mapBuffer))
399  break;
400 
401  /*
402  * We choose not to lock the page, since the result is going to be
403  * immediately stale anyway if anyone is concurrently setting or
404  * clearing bits, and we only really need an approximate value.
405  */
406  map = (uint64 *) PageGetContents(BufferGetPage(mapBuffer));
407 
408  StaticAssertStmt(MAPSIZE % sizeof(uint64) == 0,
409  "unsupported MAPSIZE");
410  if (all_frozen == NULL)
411  {
412  for (i = 0; i < MAPSIZE / sizeof(uint64); i++)
413  nvisible += pg_popcount64(map[i] & VISIBLE_MASK64);
414  }
415  else
416  {
417  for (i = 0; i < MAPSIZE / sizeof(uint64); i++)
418  {
419  nvisible += pg_popcount64(map[i] & VISIBLE_MASK64);
420  nfrozen += pg_popcount64(map[i] & FROZEN_MASK64);
421  }
422  }
423 
424  ReleaseBuffer(mapBuffer);
425  }
426 
427  *all_visible = nvisible;
428  if (all_frozen)
429  *all_frozen = nfrozen;
430 }
431 
432 /*
433  * visibilitymap_truncate - truncate the visibility map
434  *
435  * The caller must hold AccessExclusiveLock on the relation, to ensure that
436  * other backends receive the smgr invalidation event that this function sends
437  * before they access the VM again.
438  *
439  * nheapblocks is the new size of the heap.
440  */
441 void
443 {
444  BlockNumber newnblocks;
445 
446  /* last remaining block, byte, and bit */
447  BlockNumber truncBlock = HEAPBLK_TO_MAPBLOCK(nheapblocks);
448  uint32 truncByte = HEAPBLK_TO_MAPBYTE(nheapblocks);
449  uint8 truncOffset = HEAPBLK_TO_OFFSET(nheapblocks);
450 
451 #ifdef TRACE_VISIBILITYMAP
452  elog(DEBUG1, "vm_truncate %s %d", RelationGetRelationName(rel), nheapblocks);
453 #endif
454 
455  RelationOpenSmgr(rel);
456 
457  /*
458  * If no visibility map has been created yet for this relation, there's
459  * nothing to truncate.
460  */
462  return;
463 
464  /*
465  * Unless the new size is exactly at a visibility map page boundary, the
466  * tail bits in the last remaining map page, representing truncated heap
467  * blocks, need to be cleared. This is not only tidy, but also necessary
468  * because we don't get a chance to clear the bits if the heap is extended
469  * again.
470  */
471  if (truncByte != 0 || truncOffset != 0)
472  {
473  Buffer mapBuffer;
474  Page page;
475  char *map;
476 
477  newnblocks = truncBlock + 1;
478 
479  mapBuffer = vm_readbuf(rel, truncBlock, false);
480  if (!BufferIsValid(mapBuffer))
481  {
482  /* nothing to do, the file was already smaller */
483  return;
484  }
485 
486  page = BufferGetPage(mapBuffer);
487  map = PageGetContents(page);
488 
489  LockBuffer(mapBuffer, BUFFER_LOCK_EXCLUSIVE);
490 
491  /* NO EREPORT(ERROR) from here till changes are logged */
493 
494  /* Clear out the unwanted bytes. */
495  MemSet(&map[truncByte + 1], 0, MAPSIZE - (truncByte + 1));
496 
497  /*----
498  * Mask out the unwanted bits of the last remaining byte.
499  *
500  * ((1 << 0) - 1) = 00000000
501  * ((1 << 1) - 1) = 00000001
502  * ...
503  * ((1 << 6) - 1) = 00111111
504  * ((1 << 7) - 1) = 01111111
505  *----
506  */
507  map[truncByte] &= (1 << truncOffset) - 1;
508 
509  /*
510  * Truncation of a relation is WAL-logged at a higher-level, and we
511  * will be called at WAL replay. But if checksums are enabled, we need
512  * to still write a WAL record to protect against a torn page, if the
513  * page is flushed to disk before the truncation WAL record. We cannot
514  * use MarkBufferDirtyHint here, because that will not dirty the page
515  * during recovery.
516  */
517  MarkBufferDirty(mapBuffer);
519  log_newpage_buffer(mapBuffer, false);
520 
522 
523  UnlockReleaseBuffer(mapBuffer);
524  }
525  else
526  newnblocks = truncBlock;
527 
528  if (smgrnblocks(rel->rd_smgr, VISIBILITYMAP_FORKNUM) <= newnblocks)
529  {
530  /* nothing to do, the file was already smaller than requested size */
531  return;
532  }
533 
534  /* Truncate the unused VM pages, and send smgr inval message */
535  smgrtruncate(rel->rd_smgr, VISIBILITYMAP_FORKNUM, newnblocks);
536 
537  /*
538  * We might as well update the local smgr_vm_nblocks setting. smgrtruncate
539  * sent an smgr cache inval message, which will cause other backends to
540  * invalidate their copy of smgr_vm_nblocks, and this one too at the next
541  * command boundary. But this ensures it isn't outright wrong until then.
542  */
543  if (rel->rd_smgr)
544  rel->rd_smgr->smgr_vm_nblocks = newnblocks;
545 }
546 
547 /*
548  * Read a visibility map page.
549  *
550  * If the page doesn't exist, InvalidBuffer is returned, or if 'extend' is
551  * true, the visibility map file is extended.
552  */
553 static Buffer
554 vm_readbuf(Relation rel, BlockNumber blkno, bool extend)
555 {
556  Buffer buf;
557 
558  /*
559  * We might not have opened the relation at the smgr level yet, or we
560  * might have been forced to close it by a sinval message. The code below
561  * won't necessarily notice relation extension immediately when extend =
562  * false, so we rely on sinval messages to ensure that our ideas about the
563  * size of the map aren't too far out of date.
564  */
565  RelationOpenSmgr(rel);
566 
567  /*
568  * If we haven't cached the size of the visibility map fork yet, check it
569  * first.
570  */
572  {
576  else
577  rel->rd_smgr->smgr_vm_nblocks = 0;
578  }
579 
580  /* Handle requests beyond EOF */
581  if (blkno >= rel->rd_smgr->smgr_vm_nblocks)
582  {
583  if (extend)
584  vm_extend(rel, blkno + 1);
585  else
586  return InvalidBuffer;
587  }
588 
589  /*
590  * Use ZERO_ON_ERROR mode, and initialize the page if necessary. It's
591  * always safe to clear bits, so it's better to clear corrupt pages than
592  * error out.
593  *
594  * The initialize-the-page part is trickier than it looks, because of the
595  * possibility of multiple backends doing this concurrently, and our
596  * desire to not uselessly take the buffer lock in the normal path where
597  * the page is OK. We must take the lock to initialize the page, so
598  * recheck page newness after we have the lock, in case someone else
599  * already did it. Also, because we initially check PageIsNew with no
600  * lock, it's possible to fall through and return the buffer while someone
601  * else is still initializing the page (i.e., we might see pd_upper as set
602  * but other page header fields are still zeroes). This is harmless for
603  * callers that will take a buffer lock themselves, but some callers
604  * inspect the page without any lock at all. The latter is OK only so
605  * long as it doesn't depend on the page header having correct contents.
606  * Current usage is safe because PageGetContents() does not require that.
607  */
608  buf = ReadBufferExtended(rel, VISIBILITYMAP_FORKNUM, blkno,
609  RBM_ZERO_ON_ERROR, NULL);
610  if (PageIsNew(BufferGetPage(buf)))
611  {
613  if (PageIsNew(BufferGetPage(buf)))
614  PageInit(BufferGetPage(buf), BLCKSZ, 0);
616  }
617  return buf;
618 }
619 
620 /*
621  * Ensure that the visibility map fork is at least vm_nblocks long, extending
622  * it if necessary with zeroed pages.
623  */
624 static void
626 {
627  BlockNumber vm_nblocks_now;
628  PGAlignedBlock pg;
629 
630  PageInit((Page) pg.data, BLCKSZ, 0);
631 
632  /*
633  * We use the relation extension lock to lock out other backends trying to
634  * extend the visibility map at the same time. It also locks out extension
635  * of the main fork, unnecessarily, but extending the visibility map
636  * happens seldom enough that it doesn't seem worthwhile to have a
637  * separate lock tag type for it.
638  *
639  * Note that another backend might have extended or created the relation
640  * by the time we get the lock.
641  */
643 
644  /* Might have to re-open if a cache flush happened */
645  RelationOpenSmgr(rel);
646 
647  /*
648  * Create the file first if it doesn't exist. If smgr_vm_nblocks is
649  * positive then it must exist, no need for an smgrexists call.
650  */
651  if ((rel->rd_smgr->smgr_vm_nblocks == 0 ||
655 
656  vm_nblocks_now = smgrnblocks(rel->rd_smgr, VISIBILITYMAP_FORKNUM);
657 
658  /* Now extend the file */
659  while (vm_nblocks_now < vm_nblocks)
660  {
661  PageSetChecksumInplace((Page) pg.data, vm_nblocks_now);
662 
663  smgrextend(rel->rd_smgr, VISIBILITYMAP_FORKNUM, vm_nblocks_now,
664  pg.data, false);
665  vm_nblocks_now++;
666  }
667 
668  /*
669  * Send a shared-inval message to force other backends to close any smgr
670  * references they may have for this rel, which we are about to change.
671  * This is a useful optimization because it means that backends don't have
672  * to keep checking for creation or extension of the file, which happens
673  * infrequently.
674  */
676 
677  /* Update local cache with the up-to-date size */
678  rel->rd_smgr->smgr_vm_nblocks = vm_nblocks_now;
679 
681 }
void CacheInvalidateSmgr(RelFileNodeBackend rnode)
Definition: inval.c:1369
#define BUFFER_LOCK_UNLOCK
Definition: bufmgr.h:86
BlockNumber smgr_vm_nblocks
Definition: smgr.h:56
#define DEBUG1
Definition: elog.h:25
XLogRecPtr log_newpage_buffer(Buffer buffer, bool page_std)
Definition: xloginsert.c:1009
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Definition: smgr.c:333
#define PageIsAllVisible(page)
Definition: bufpage.h:385
uint32 TransactionId
Definition: c.h:507
void visibilitymap_pin(Relation rel, BlockNumber heapBlk, Buffer *buf)
static void vm_extend(Relation rel, BlockNumber vm_nblocks)
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Definition: bufmgr.c:1458
#define ExclusiveLock
Definition: lockdefs.h:44
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Definition: rel.h:56
Buffer ReadBufferExtended(Relation reln, ForkNumber forkNum, BlockNumber blockNum, ReadBufferMode mode, BufferAccessStrategy strategy)
Definition: bufmgr.c:642
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Definition: xlog.c:200
#define END_CRIT_SECTION()
Definition: miscadmin.h:134
unsigned char uint8
Definition: c.h:356
#define HEAPBLK_TO_MAPBYTE(x)
#define InvalidBuffer
Definition: buf.h:25
void smgrtruncate(SMgrRelation reln, ForkNumber forknum, BlockNumber nblocks)
Definition: smgr.c:621
#define START_CRIT_SECTION()
Definition: miscadmin.h:132
#define MemSet(start, val, len)
Definition: c.h:955
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Definition: block.h:31
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Definition: bufmgr.c:3353
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Definition: smgr.c:247
void visibilitymap_count(Relation rel, BlockNumber *all_visible, BlockNumber *all_frozen)
#define BUFFER_LOCK_EXCLUSIVE
Definition: bufmgr.h:88
#define VISIBILITYMAP_VALID_BITS
Definition: visibilitymap.h:28
#define RelationOpenSmgr(relation)
Definition: rel.h:473
#define StaticAssertStmt(condition, errmessage)
Definition: c.h:842
char data[BLCKSZ]
Definition: c.h:1060
bool visibilitymap_clear(Relation rel, BlockNumber heapBlk, Buffer buf, uint8 flags)
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Definition: bufmgr.c:3376
#define ERROR
Definition: elog.h:43
XLogRecPtr log_heap_visible(RelFileNode rnode, Buffer heap_buffer, Buffer vm_buffer, TransactionId cutoff_xid, uint8 vmflags)
Definition: heapam.c:7268
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Definition: smgr.h:42
static char * buf
Definition: pg_test_fsync.c:68
int(* pg_popcount64)(uint64 word)
Definition: pg_bitutils.c:133
#define RelationGetRelationName(relation)
Definition: rel.h:450
unsigned int uint32
Definition: c.h:358
#define VISIBLE_MASK64
#define MAPSIZE
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Definition: bufmgr.h:159
#define XLogRecPtrIsInvalid(r)
Definition: xlogdefs.h:29
void LockRelationForExtension(Relation relation, LOCKMODE lockmode)
Definition: lmgr.c:402
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Definition: lmgr.c:452
#define PageGetContents(page)
Definition: bufpage.h:246
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Definition: bufmgr.c:3590
RelFileNode rd_node
Definition: rel.h:54
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Definition: smgr.c:609
uint64 XLogRecPtr
Definition: xlogdefs.h:21
#define Assert(condition)
Definition: c.h:732
void visibilitymap_truncate(Relation rel, BlockNumber nheapblocks)
#define HEAPBLK_TO_OFFSET(x)
#define InvalidBlockNumber
Definition: block.h:33
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Definition: bufpage.c:1198
#define BufferIsValid(bufnum)
Definition: bufmgr.h:113
#define RelationNeedsWAL(relation)
Definition: rel.h:518
void smgrextend(SMgrRelation reln, ForkNumber forknum, BlockNumber blocknum, char *buffer, bool skipFsync)
Definition: smgr.c:537
#define FROZEN_MASK64
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Definition: bufmgr.c:2613
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Definition: bufpage.h:229
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#define elog(elevel,...)
Definition: elog.h:226
int i
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Definition: bufpage.h:368
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Definition: buf.h:23
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Definition: xlog.h:192
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Definition: bufpage.h:78
#define HEAPBLK_TO_MAPBLOCK(x)
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Definition: bufpage.c:42