Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * pruneheap.c
4 : * heap page pruning and HOT-chain management code
5 : *
6 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
7 : * Portions Copyright (c) 1994, Regents of the University of California
8 : *
9 : *
10 : * IDENTIFICATION
11 : * src/backend/access/heap/pruneheap.c
12 : *
13 : *-------------------------------------------------------------------------
14 : */
15 : #include "postgres.h"
16 :
17 : #include "access/heapam.h"
18 : #include "access/heapam_xlog.h"
19 : #include "access/htup_details.h"
20 : #include "access/multixact.h"
21 : #include "access/transam.h"
22 : #include "access/visibilitymapdefs.h"
23 : #include "access/xlog.h"
24 : #include "access/xloginsert.h"
25 : #include "commands/vacuum.h"
26 : #include "executor/instrument.h"
27 : #include "miscadmin.h"
28 : #include "pgstat.h"
29 : #include "storage/bufmgr.h"
30 : #include "utils/rel.h"
31 : #include "utils/snapmgr.h"
32 :
33 : /* Working data for heap_page_prune_and_freeze() and subroutines */
34 : typedef struct
35 : {
36 : /*-------------------------------------------------------
37 : * Arguments passed to heap_page_prune_and_freeze()
38 : *-------------------------------------------------------
39 : */
40 :
41 : /* tuple visibility test, initialized for the relation */
42 : GlobalVisState *vistest;
43 : /* whether or not dead items can be set LP_UNUSED during pruning */
44 : bool mark_unused_now;
45 : /* whether to attempt freezing tuples */
46 : bool attempt_freeze;
47 : struct VacuumCutoffs *cutoffs;
48 :
49 : /*-------------------------------------------------------
50 : * Fields describing what to do to the page
51 : *-------------------------------------------------------
52 : */
53 : TransactionId new_prune_xid; /* new prune hint value */
54 : TransactionId latest_xid_removed;
55 : int nredirected; /* numbers of entries in arrays below */
56 : int ndead;
57 : int nunused;
58 : int nfrozen;
59 : /* arrays that accumulate indexes of items to be changed */
60 : OffsetNumber redirected[MaxHeapTuplesPerPage * 2];
61 : OffsetNumber nowdead[MaxHeapTuplesPerPage];
62 : OffsetNumber nowunused[MaxHeapTuplesPerPage];
63 : HeapTupleFreeze frozen[MaxHeapTuplesPerPage];
64 :
65 : /*-------------------------------------------------------
66 : * Working state for HOT chain processing
67 : *-------------------------------------------------------
68 : */
69 :
70 : /*
71 : * 'root_items' contains offsets of all LP_REDIRECT line pointers and
72 : * normal non-HOT tuples. They can be stand-alone items or the first item
73 : * in a HOT chain. 'heaponly_items' contains heap-only tuples which can
74 : * only be removed as part of a HOT chain.
75 : */
76 : int nroot_items;
77 : OffsetNumber root_items[MaxHeapTuplesPerPage];
78 : int nheaponly_items;
79 : OffsetNumber heaponly_items[MaxHeapTuplesPerPage];
80 :
81 : /*
82 : * processed[offnum] is true if item at offnum has been processed.
83 : *
84 : * This needs to be MaxHeapTuplesPerPage + 1 long as FirstOffsetNumber is
85 : * 1. Otherwise every access would need to subtract 1.
86 : */
87 : bool processed[MaxHeapTuplesPerPage + 1];
88 :
89 : /*
90 : * Tuple visibility is only computed once for each tuple, for correctness
91 : * and efficiency reasons; see comment in heap_page_prune_and_freeze() for
92 : * details. This is of type int8[], instead of HTSV_Result[], so we can
93 : * use -1 to indicate no visibility has been computed, e.g. for LP_DEAD
94 : * items.
95 : *
96 : * This needs to be MaxHeapTuplesPerPage + 1 long as FirstOffsetNumber is
97 : * 1. Otherwise every access would need to subtract 1.
98 : */
99 : int8 htsv[MaxHeapTuplesPerPage + 1];
100 :
101 : /*
102 : * Freezing-related state.
103 : */
104 : HeapPageFreeze pagefrz;
105 :
106 : /*-------------------------------------------------------
107 : * Information about what was done
108 : *
109 : * These fields are not used by pruning itself for the most part, but are
110 : * used to collect information about what was pruned and what state the
111 : * page is in after pruning, for the benefit of the caller. They are
112 : * copied to the caller's PruneFreezeResult at the end.
113 : * -------------------------------------------------------
114 : */
115 :
116 : int ndeleted; /* Number of tuples deleted from the page */
117 :
118 : /* Number of live and recently dead tuples, after pruning */
119 : int live_tuples;
120 : int recently_dead_tuples;
121 :
122 : /* Whether or not the page makes rel truncation unsafe */
123 : bool hastup;
124 :
125 : /*
126 : * LP_DEAD items on the page after pruning. Includes existing LP_DEAD
127 : * items
128 : */
129 : int lpdead_items; /* number of items in the array */
130 : OffsetNumber *deadoffsets; /* points directly to presult->deadoffsets */
131 :
132 : /*
133 : * The snapshot conflict horizon used when freezing tuples. The final
134 : * snapshot conflict horizon for the record may be newer if pruning
135 : * removes newer transaction IDs.
136 : */
137 : TransactionId frz_conflict_horizon;
138 :
139 : /*
140 : * all_visible and all_frozen indicate if the all-visible and all-frozen
141 : * bits in the visibility map can be set for this page after pruning.
142 : *
143 : * visibility_cutoff_xid is the newest xmin of live tuples on the page.
144 : * The caller can use it as the conflict horizon, when setting the VM
145 : * bits. It is only valid if we froze some tuples, and all_frozen is
146 : * true.
147 : *
148 : * NOTE: all_visible and all_frozen initially don't include LP_DEAD items.
149 : * That's convenient for heap_page_prune_and_freeze() to use them to
150 : * decide whether to freeze the page or not. The all_visible and
151 : * all_frozen values returned to the caller are adjusted to include
152 : * LP_DEAD items after we determine whether to opportunistically freeze.
153 : */
154 : bool all_visible;
155 : bool all_frozen;
156 : TransactionId visibility_cutoff_xid;
157 : } PruneState;
158 :
159 : /* Local functions */
160 : static void prune_freeze_setup(PruneFreezeParams *params,
161 : TransactionId *new_relfrozen_xid,
162 : MultiXactId *new_relmin_mxid,
163 : PruneFreezeResult *presult,
164 : PruneState *prstate);
165 : static void prune_freeze_plan(Oid reloid, Buffer buffer,
166 : PruneState *prstate,
167 : OffsetNumber *off_loc);
168 : static HTSV_Result heap_prune_satisfies_vacuum(PruneState *prstate,
169 : HeapTuple tup,
170 : Buffer buffer);
171 : static inline HTSV_Result htsv_get_valid_status(int status);
172 : static void heap_prune_chain(Page page, BlockNumber blockno, OffsetNumber maxoff,
173 : OffsetNumber rootoffnum, PruneState *prstate);
174 : static void heap_prune_record_prunable(PruneState *prstate, TransactionId xid);
175 : static void heap_prune_record_redirect(PruneState *prstate,
176 : OffsetNumber offnum, OffsetNumber rdoffnum,
177 : bool was_normal);
178 : static void heap_prune_record_dead(PruneState *prstate, OffsetNumber offnum,
179 : bool was_normal);
180 : static void heap_prune_record_dead_or_unused(PruneState *prstate, OffsetNumber offnum,
181 : bool was_normal);
182 : static void heap_prune_record_unused(PruneState *prstate, OffsetNumber offnum, bool was_normal);
183 :
184 : static void heap_prune_record_unchanged_lp_unused(Page page, PruneState *prstate, OffsetNumber offnum);
185 : static void heap_prune_record_unchanged_lp_normal(Page page, PruneState *prstate, OffsetNumber offnum);
186 : static void heap_prune_record_unchanged_lp_dead(Page page, PruneState *prstate, OffsetNumber offnum);
187 : static void heap_prune_record_unchanged_lp_redirect(PruneState *prstate, OffsetNumber offnum);
188 :
189 : static void page_verify_redirects(Page page);
190 :
191 : static bool heap_page_will_freeze(Relation relation, Buffer buffer,
192 : bool did_tuple_hint_fpi, bool do_prune, bool do_hint_prune,
193 : PruneState *prstate);
194 :
195 :
196 : /*
197 : * Optionally prune and repair fragmentation in the specified page.
198 : *
199 : * This is an opportunistic function. It will perform housekeeping
200 : * only if the page heuristically looks like a candidate for pruning and we
201 : * can acquire buffer cleanup lock without blocking.
202 : *
203 : * Note: this is called quite often. It's important that it fall out quickly
204 : * if there's not any use in pruning.
205 : *
206 : * Caller must have pin on the buffer, and must *not* have a lock on it.
207 : */
208 : void
209 33524232 : heap_page_prune_opt(Relation relation, Buffer buffer)
210 : {
211 33524232 : Page page = BufferGetPage(buffer);
212 : TransactionId prune_xid;
213 : GlobalVisState *vistest;
214 : Size minfree;
215 :
216 : /*
217 : * We can't write WAL in recovery mode, so there's no point trying to
218 : * clean the page. The primary will likely issue a cleaning WAL record
219 : * soon anyway, so this is no particular loss.
220 : */
221 33524232 : if (RecoveryInProgress())
222 420662 : return;
223 :
224 : /*
225 : * First check whether there's any chance there's something to prune,
226 : * determining the appropriate horizon is a waste if there's no prune_xid
227 : * (i.e. no updates/deletes left potentially dead tuples around).
228 : */
229 33103570 : prune_xid = ((PageHeader) page)->pd_prune_xid;
230 33103570 : if (!TransactionIdIsValid(prune_xid))
231 17237210 : return;
232 :
233 : /*
234 : * Check whether prune_xid indicates that there may be dead rows that can
235 : * be cleaned up.
236 : */
237 15866360 : vistest = GlobalVisTestFor(relation);
238 :
239 15866360 : if (!GlobalVisTestIsRemovableXid(vistest, prune_xid))
240 13175154 : return;
241 :
242 : /*
243 : * We prune when a previous UPDATE failed to find enough space on the page
244 : * for a new tuple version, or when free space falls below the relation's
245 : * fill-factor target (but not less than 10%).
246 : *
247 : * Checking free space here is questionable since we aren't holding any
248 : * lock on the buffer; in the worst case we could get a bogus answer. It's
249 : * unlikely to be *seriously* wrong, though, since reading either pd_lower
250 : * or pd_upper is probably atomic. Avoiding taking a lock seems more
251 : * important than sometimes getting a wrong answer in what is after all
252 : * just a heuristic estimate.
253 : */
254 2691206 : minfree = RelationGetTargetPageFreeSpace(relation,
255 : HEAP_DEFAULT_FILLFACTOR);
256 2691206 : minfree = Max(minfree, BLCKSZ / 10);
257 :
258 2691206 : if (PageIsFull(page) || PageGetHeapFreeSpace(page) < minfree)
259 : {
260 : /* OK, try to get exclusive buffer lock */
261 85962 : if (!ConditionalLockBufferForCleanup(buffer))
262 950 : return;
263 :
264 : /*
265 : * Now that we have buffer lock, get accurate information about the
266 : * page's free space, and recheck the heuristic about whether to
267 : * prune.
268 : */
269 85012 : if (PageIsFull(page) || PageGetHeapFreeSpace(page) < minfree)
270 : {
271 : OffsetNumber dummy_off_loc;
272 : PruneFreezeResult presult;
273 :
274 : /*
275 : * We don't pass the HEAP_PAGE_PRUNE_MARK_UNUSED_NOW option
276 : * regardless of whether or not the relation has indexes, since we
277 : * cannot safely determine that during on-access pruning with the
278 : * current implementation.
279 : */
280 85012 : PruneFreezeParams params = {
281 : .relation = relation,
282 : .buffer = buffer,
283 : .reason = PRUNE_ON_ACCESS,
284 : .options = 0,
285 : .vistest = vistest,
286 : .cutoffs = NULL,
287 : };
288 :
289 85012 : heap_page_prune_and_freeze(¶ms, &presult, &dummy_off_loc,
290 : NULL, NULL);
291 :
292 : /*
293 : * Report the number of tuples reclaimed to pgstats. This is
294 : * presult.ndeleted minus the number of newly-LP_DEAD-set items.
295 : *
296 : * We derive the number of dead tuples like this to avoid totally
297 : * forgetting about items that were set to LP_DEAD, since they
298 : * still need to be cleaned up by VACUUM. We only want to count
299 : * heap-only tuples that just became LP_UNUSED in our report,
300 : * which don't.
301 : *
302 : * VACUUM doesn't have to compensate in the same way when it
303 : * tracks ndeleted, since it will set the same LP_DEAD items to
304 : * LP_UNUSED separately.
305 : */
306 85012 : if (presult.ndeleted > presult.nnewlpdead)
307 39498 : pgstat_update_heap_dead_tuples(relation,
308 39498 : presult.ndeleted - presult.nnewlpdead);
309 : }
310 :
311 : /* And release buffer lock */
312 85012 : LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
313 :
314 : /*
315 : * We avoid reuse of any free space created on the page by unrelated
316 : * UPDATEs/INSERTs by opting to not update the FSM at this point. The
317 : * free space should be reused by UPDATEs to *this* page.
318 : */
319 : }
320 : }
321 :
322 : /*
323 : * Helper for heap_page_prune_and_freeze() to initialize the PruneState using
324 : * the provided parameters.
325 : *
326 : * params, new_relfrozen_xid, new_relmin_mxid, and presult are input
327 : * parameters and are not modified by this function. Only prstate is modified.
328 : */
329 : static void
330 1039046 : prune_freeze_setup(PruneFreezeParams *params,
331 : TransactionId *new_relfrozen_xid,
332 : MultiXactId *new_relmin_mxid,
333 : PruneFreezeResult *presult,
334 : PruneState *prstate)
335 : {
336 : /* Copy parameters to prstate */
337 1039046 : prstate->vistest = params->vistest;
338 1039046 : prstate->mark_unused_now =
339 1039046 : (params->options & HEAP_PAGE_PRUNE_MARK_UNUSED_NOW) != 0;
340 :
341 : /* cutoffs must be provided if we will attempt freezing */
342 : Assert(!(params->options & HEAP_PAGE_PRUNE_FREEZE) || params->cutoffs);
343 1039046 : prstate->attempt_freeze = (params->options & HEAP_PAGE_PRUNE_FREEZE) != 0;
344 1039046 : prstate->cutoffs = params->cutoffs;
345 :
346 : /*
347 : * Our strategy is to scan the page and make lists of items to change,
348 : * then apply the changes within a critical section. This keeps as much
349 : * logic as possible out of the critical section, and also ensures that
350 : * WAL replay will work the same as the normal case.
351 : *
352 : * First, initialize the new pd_prune_xid value to zero (indicating no
353 : * prunable tuples). If we find any tuples which may soon become
354 : * prunable, we will save the lowest relevant XID in new_prune_xid. Also
355 : * initialize the rest of our working state.
356 : */
357 1039046 : prstate->new_prune_xid = InvalidTransactionId;
358 1039046 : prstate->latest_xid_removed = InvalidTransactionId;
359 1039046 : prstate->nredirected = prstate->ndead = prstate->nunused = 0;
360 1039046 : prstate->nfrozen = 0;
361 1039046 : prstate->nroot_items = 0;
362 1039046 : prstate->nheaponly_items = 0;
363 :
364 : /* initialize page freezing working state */
365 1039046 : prstate->pagefrz.freeze_required = false;
366 1039046 : if (prstate->attempt_freeze)
367 : {
368 : Assert(new_relfrozen_xid && new_relmin_mxid);
369 954034 : prstate->pagefrz.FreezePageRelfrozenXid = *new_relfrozen_xid;
370 954034 : prstate->pagefrz.NoFreezePageRelfrozenXid = *new_relfrozen_xid;
371 954034 : prstate->pagefrz.FreezePageRelminMxid = *new_relmin_mxid;
372 954034 : prstate->pagefrz.NoFreezePageRelminMxid = *new_relmin_mxid;
373 : }
374 : else
375 : {
376 : Assert(!new_relfrozen_xid && !new_relmin_mxid);
377 85012 : prstate->pagefrz.FreezePageRelminMxid = InvalidMultiXactId;
378 85012 : prstate->pagefrz.NoFreezePageRelminMxid = InvalidMultiXactId;
379 85012 : prstate->pagefrz.FreezePageRelfrozenXid = InvalidTransactionId;
380 85012 : prstate->pagefrz.NoFreezePageRelfrozenXid = InvalidTransactionId;
381 : }
382 :
383 1039046 : prstate->ndeleted = 0;
384 1039046 : prstate->live_tuples = 0;
385 1039046 : prstate->recently_dead_tuples = 0;
386 1039046 : prstate->hastup = false;
387 1039046 : prstate->lpdead_items = 0;
388 :
389 : /*
390 : * deadoffsets are filled in during pruning but are only used to populate
391 : * PruneFreezeResult->deadoffsets. To avoid needing two copies of the
392 : * array, just save a pointer to the result offsets array in the
393 : * PruneState.
394 : */
395 1039046 : prstate->deadoffsets = presult->deadoffsets;
396 1039046 : prstate->frz_conflict_horizon = InvalidTransactionId;
397 :
398 : /*
399 : * Vacuum may update the VM after we're done. We can keep track of
400 : * whether the page will be all-visible and all-frozen after pruning and
401 : * freezing to help the caller to do that.
402 : *
403 : * Currently, only VACUUM sets the VM bits. To save the effort, only do
404 : * the bookkeeping if the caller needs it. Currently, that's tied to
405 : * HEAP_PAGE_PRUNE_FREEZE, but it could be a separate flag if you wanted
406 : * to update the VM bits without also freezing or freeze without also
407 : * setting the VM bits.
408 : *
409 : * In addition to telling the caller whether it can set the VM bit, we
410 : * also use 'all_visible' and 'all_frozen' for our own decision-making. If
411 : * the whole page would become frozen, we consider opportunistically
412 : * freezing tuples. We will not be able to freeze the whole page if there
413 : * are tuples present that are not visible to everyone or if there are
414 : * dead tuples which are not yet removable. However, dead tuples which
415 : * will be removed by the end of vacuuming should not preclude us from
416 : * opportunistically freezing. Because of that, we do not immediately
417 : * clear all_visible and all_frozen when we see LP_DEAD items. We fix
418 : * that after scanning the line pointers. We must correct all_visible and
419 : * all_frozen before we return them to the caller, so that the caller
420 : * doesn't set the VM bits incorrectly.
421 : */
422 1039046 : if (prstate->attempt_freeze)
423 : {
424 954034 : prstate->all_visible = true;
425 954034 : prstate->all_frozen = true;
426 : }
427 : else
428 : {
429 : /*
430 : * Initializing to false allows skipping the work to update them in
431 : * heap_prune_record_unchanged_lp_normal().
432 : */
433 85012 : prstate->all_visible = false;
434 85012 : prstate->all_frozen = false;
435 : }
436 :
437 : /*
438 : * The visibility cutoff xid is the newest xmin of live tuples on the
439 : * page. In the common case, this will be set as the conflict horizon the
440 : * caller can use for updating the VM. If, at the end of freezing and
441 : * pruning, the page is all-frozen, there is no possibility that any
442 : * running transaction on the standby does not see tuples on the page as
443 : * all-visible, so the conflict horizon remains InvalidTransactionId.
444 : */
445 1039046 : prstate->visibility_cutoff_xid = InvalidTransactionId;
446 1039046 : }
447 :
448 : /*
449 : * Helper for heap_page_prune_and_freeze(). Iterates over every tuple on the
450 : * page, examines its visibility information, and determines the appropriate
451 : * action for each tuple. All tuples are processed and classified during this
452 : * phase, but no modifications are made to the page until the later execution
453 : * stage.
454 : *
455 : * *off_loc is used for error callback and cleared before returning.
456 : */
457 : static void
458 1039046 : prune_freeze_plan(Oid reloid, Buffer buffer, PruneState *prstate,
459 : OffsetNumber *off_loc)
460 : {
461 1039046 : Page page = BufferGetPage(buffer);
462 1039046 : BlockNumber blockno = BufferGetBlockNumber(buffer);
463 1039046 : OffsetNumber maxoff = PageGetMaxOffsetNumber(page);
464 : OffsetNumber offnum;
465 : HeapTupleData tup;
466 :
467 1039046 : tup.t_tableOid = reloid;
468 :
469 : /*
470 : * Determine HTSV for all tuples, and queue them up for processing as HOT
471 : * chain roots or as heap-only items.
472 : *
473 : * Determining HTSV only once for each tuple is required for correctness,
474 : * to deal with cases where running HTSV twice could result in different
475 : * results. For example, RECENTLY_DEAD can turn to DEAD if another
476 : * checked item causes GlobalVisTestIsRemovableFullXid() to update the
477 : * horizon, or INSERT_IN_PROGRESS can change to DEAD if the inserting
478 : * transaction aborts.
479 : *
480 : * It's also good for performance. Most commonly tuples within a page are
481 : * stored at decreasing offsets (while the items are stored at increasing
482 : * offsets). When processing all tuples on a page this leads to reading
483 : * memory at decreasing offsets within a page, with a variable stride.
484 : * That's hard for CPU prefetchers to deal with. Processing the items in
485 : * reverse order (and thus the tuples in increasing order) increases
486 : * prefetching efficiency significantly / decreases the number of cache
487 : * misses.
488 : */
489 1039046 : for (offnum = maxoff;
490 53644364 : offnum >= FirstOffsetNumber;
491 52605318 : offnum = OffsetNumberPrev(offnum))
492 : {
493 52605318 : ItemId itemid = PageGetItemId(page, offnum);
494 : HeapTupleHeader htup;
495 :
496 : /*
497 : * Set the offset number so that we can display it along with any
498 : * error that occurred while processing this tuple.
499 : */
500 52605318 : *off_loc = offnum;
501 :
502 52605318 : prstate->processed[offnum] = false;
503 52605318 : prstate->htsv[offnum] = -1;
504 :
505 : /* Nothing to do if slot doesn't contain a tuple */
506 52605318 : if (!ItemIdIsUsed(itemid))
507 : {
508 642676 : heap_prune_record_unchanged_lp_unused(page, prstate, offnum);
509 642676 : continue;
510 : }
511 :
512 51962642 : if (ItemIdIsDead(itemid))
513 : {
514 : /*
515 : * If the caller set mark_unused_now true, we can set dead line
516 : * pointers LP_UNUSED now.
517 : */
518 1977078 : if (unlikely(prstate->mark_unused_now))
519 0 : heap_prune_record_unused(prstate, offnum, false);
520 : else
521 1977078 : heap_prune_record_unchanged_lp_dead(page, prstate, offnum);
522 1977078 : continue;
523 : }
524 :
525 49985564 : if (ItemIdIsRedirected(itemid))
526 : {
527 : /* This is the start of a HOT chain */
528 665094 : prstate->root_items[prstate->nroot_items++] = offnum;
529 665094 : continue;
530 : }
531 :
532 : Assert(ItemIdIsNormal(itemid));
533 :
534 : /*
535 : * Get the tuple's visibility status and queue it up for processing.
536 : */
537 49320470 : htup = (HeapTupleHeader) PageGetItem(page, itemid);
538 49320470 : tup.t_data = htup;
539 49320470 : tup.t_len = ItemIdGetLength(itemid);
540 49320470 : ItemPointerSet(&tup.t_self, blockno, offnum);
541 :
542 49320470 : prstate->htsv[offnum] = heap_prune_satisfies_vacuum(prstate, &tup,
543 : buffer);
544 :
545 49320470 : if (!HeapTupleHeaderIsHeapOnly(htup))
546 48407422 : prstate->root_items[prstate->nroot_items++] = offnum;
547 : else
548 913048 : prstate->heaponly_items[prstate->nheaponly_items++] = offnum;
549 : }
550 :
551 : /*
552 : * Process HOT chains.
553 : *
554 : * We added the items to the array starting from 'maxoff', so by
555 : * processing the array in reverse order, we process the items in
556 : * ascending offset number order. The order doesn't matter for
557 : * correctness, but some quick micro-benchmarking suggests that this is
558 : * faster. (Earlier PostgreSQL versions, which scanned all the items on
559 : * the page instead of using the root_items array, also did it in
560 : * ascending offset number order.)
561 : */
562 50111562 : for (int i = prstate->nroot_items - 1; i >= 0; i--)
563 : {
564 49072516 : offnum = prstate->root_items[i];
565 :
566 : /* Ignore items already processed as part of an earlier chain */
567 49072516 : if (prstate->processed[offnum])
568 0 : continue;
569 :
570 : /* see preceding loop */
571 49072516 : *off_loc = offnum;
572 :
573 : /* Process this item or chain of items */
574 49072516 : heap_prune_chain(page, blockno, maxoff, offnum, prstate);
575 : }
576 :
577 : /*
578 : * Process any heap-only tuples that were not already processed as part of
579 : * a HOT chain.
580 : */
581 1952094 : for (int i = prstate->nheaponly_items - 1; i >= 0; i--)
582 : {
583 913048 : offnum = prstate->heaponly_items[i];
584 :
585 913048 : if (prstate->processed[offnum])
586 885188 : continue;
587 :
588 : /* see preceding loop */
589 27860 : *off_loc = offnum;
590 :
591 : /*
592 : * If the tuple is DEAD and doesn't chain to anything else, mark it
593 : * unused. (If it does chain, we can only remove it as part of
594 : * pruning its chain.)
595 : *
596 : * We need this primarily to handle aborted HOT updates, that is,
597 : * XMIN_INVALID heap-only tuples. Those might not be linked to by any
598 : * chain, since the parent tuple might be re-updated before any
599 : * pruning occurs. So we have to be able to reap them separately from
600 : * chain-pruning. (Note that HeapTupleHeaderIsHotUpdated will never
601 : * return true for an XMIN_INVALID tuple, so this code will work even
602 : * when there were sequential updates within the aborted transaction.)
603 : */
604 27860 : if (prstate->htsv[offnum] == HEAPTUPLE_DEAD)
605 : {
606 4276 : ItemId itemid = PageGetItemId(page, offnum);
607 4276 : HeapTupleHeader htup = (HeapTupleHeader) PageGetItem(page, itemid);
608 :
609 4276 : if (likely(!HeapTupleHeaderIsHotUpdated(htup)))
610 : {
611 4276 : HeapTupleHeaderAdvanceConflictHorizon(htup,
612 : &prstate->latest_xid_removed);
613 4276 : heap_prune_record_unused(prstate, offnum, true);
614 : }
615 : else
616 : {
617 : /*
618 : * This tuple should've been processed and removed as part of
619 : * a HOT chain, so something's wrong. To preserve evidence,
620 : * we don't dare to remove it. We cannot leave behind a DEAD
621 : * tuple either, because that will cause VACUUM to error out.
622 : * Throwing an error with a distinct error message seems like
623 : * the least bad option.
624 : */
625 0 : elog(ERROR, "dead heap-only tuple (%u, %d) is not linked to from any HOT chain",
626 : blockno, offnum);
627 : }
628 : }
629 : else
630 23584 : heap_prune_record_unchanged_lp_normal(page, prstate, offnum);
631 : }
632 :
633 : /* We should now have processed every tuple exactly once */
634 : #ifdef USE_ASSERT_CHECKING
635 : for (offnum = FirstOffsetNumber;
636 : offnum <= maxoff;
637 : offnum = OffsetNumberNext(offnum))
638 : {
639 : *off_loc = offnum;
640 :
641 : Assert(prstate->processed[offnum]);
642 : }
643 : #endif
644 :
645 : /* Clear the offset information once we have processed the given page. */
646 1039046 : *off_loc = InvalidOffsetNumber;
647 1039046 : }
648 :
649 : /*
650 : * Decide whether to proceed with freezing according to the freeze plans
651 : * prepared for the given heap buffer. If freezing is chosen, this function
652 : * performs several pre-freeze checks.
653 : *
654 : * The values of do_prune, do_hint_prune, and did_tuple_hint_fpi must be
655 : * determined before calling this function.
656 : *
657 : * prstate is both an input and output parameter.
658 : *
659 : * Returns true if we should apply the freeze plans and freeze tuples on the
660 : * page, and false otherwise.
661 : */
662 : static bool
663 1039046 : heap_page_will_freeze(Relation relation, Buffer buffer,
664 : bool did_tuple_hint_fpi,
665 : bool do_prune,
666 : bool do_hint_prune,
667 : PruneState *prstate)
668 : {
669 1039046 : bool do_freeze = false;
670 :
671 : /*
672 : * If the caller specified we should not attempt to freeze any tuples,
673 : * validate that everything is in the right state and return.
674 : */
675 1039046 : if (!prstate->attempt_freeze)
676 : {
677 : Assert(!prstate->all_frozen && prstate->nfrozen == 0);
678 : Assert(prstate->lpdead_items == 0 || !prstate->all_visible);
679 85012 : return false;
680 : }
681 :
682 954034 : if (prstate->pagefrz.freeze_required)
683 : {
684 : /*
685 : * heap_prepare_freeze_tuple indicated that at least one XID/MXID from
686 : * before FreezeLimit/MultiXactCutoff is present. Must freeze to
687 : * advance relfrozenxid/relminmxid.
688 : */
689 42320 : do_freeze = true;
690 : }
691 : else
692 : {
693 : /*
694 : * Opportunistically freeze the page if we are generating an FPI
695 : * anyway and if doing so means that we can set the page all-frozen
696 : * afterwards (might not happen until VACUUM's final heap pass).
697 : *
698 : * XXX: Previously, we knew if pruning emitted an FPI by checking
699 : * pgWalUsage.wal_fpi before and after pruning. Once the freeze and
700 : * prune records were combined, this heuristic couldn't be used
701 : * anymore. The opportunistic freeze heuristic must be improved;
702 : * however, for now, try to approximate the old logic.
703 : */
704 911714 : if (prstate->all_frozen && prstate->nfrozen > 0)
705 : {
706 : Assert(prstate->all_visible);
707 :
708 : /*
709 : * Freezing would make the page all-frozen. Have already emitted
710 : * an FPI or will do so anyway?
711 : */
712 27770 : if (RelationNeedsWAL(relation))
713 : {
714 24458 : if (did_tuple_hint_fpi)
715 2464 : do_freeze = true;
716 21994 : else if (do_prune)
717 : {
718 2162 : if (XLogCheckBufferNeedsBackup(buffer))
719 1320 : do_freeze = true;
720 : }
721 19832 : else if (do_hint_prune)
722 : {
723 10 : if (XLogHintBitIsNeeded() && XLogCheckBufferNeedsBackup(buffer))
724 6 : do_freeze = true;
725 : }
726 : }
727 : }
728 : }
729 :
730 954034 : if (do_freeze)
731 : {
732 : /*
733 : * Validate the tuples we will be freezing before entering the
734 : * critical section.
735 : */
736 46110 : heap_pre_freeze_checks(buffer, prstate->frozen, prstate->nfrozen);
737 :
738 : /*
739 : * Calculate what the snapshot conflict horizon should be for a record
740 : * freezing tuples. We can use the visibility_cutoff_xid as our cutoff
741 : * for conflicts when the whole page is eligible to become all-frozen
742 : * in the VM once we're done with it. Otherwise, we generate a
743 : * conservative cutoff by stepping back from OldestXmin.
744 : */
745 46110 : if (prstate->all_frozen)
746 41416 : prstate->frz_conflict_horizon = prstate->visibility_cutoff_xid;
747 : else
748 : {
749 : /* Avoids false conflicts when hot_standby_feedback in use */
750 4694 : prstate->frz_conflict_horizon = prstate->cutoffs->OldestXmin;
751 4694 : TransactionIdRetreat(prstate->frz_conflict_horizon);
752 : }
753 : }
754 907924 : else if (prstate->nfrozen > 0)
755 : {
756 : /*
757 : * The page contained some tuples that were not already frozen, and we
758 : * chose not to freeze them now. The page won't be all-frozen then.
759 : */
760 : Assert(!prstate->pagefrz.freeze_required);
761 :
762 24840 : prstate->all_frozen = false;
763 24840 : prstate->nfrozen = 0; /* avoid miscounts in instrumentation */
764 : }
765 : else
766 : {
767 : /*
768 : * We have no freeze plans to execute. The page might already be
769 : * all-frozen (perhaps only following pruning), though. Such pages
770 : * can be marked all-frozen in the VM by our caller, even though none
771 : * of its tuples were newly frozen here.
772 : */
773 : }
774 :
775 954034 : return do_freeze;
776 : }
777 :
778 :
779 : /*
780 : * Prune and repair fragmentation and potentially freeze tuples on the
781 : * specified page.
782 : *
783 : * Caller must have pin and buffer cleanup lock on the page. Note that we
784 : * don't update the FSM information for page on caller's behalf. Caller might
785 : * also need to account for a reduction in the length of the line pointer
786 : * array following array truncation by us.
787 : *
788 : * params contains the input parameters used to control freezing and pruning
789 : * behavior. See the definition of PruneFreezeParams for more on what each
790 : * parameter does.
791 : *
792 : * If the HEAP_PAGE_PRUNE_FREEZE option is set in params, we will freeze
793 : * tuples if it's required in order to advance relfrozenxid / relminmxid, or
794 : * if it's considered advantageous for overall system performance to do so
795 : * now. The 'params.cutoffs', 'presult', 'new_relfrozen_xid' and
796 : * 'new_relmin_mxid' arguments are required when freezing. When
797 : * HEAP_PAGE_PRUNE_FREEZE option is passed, we also set presult->all_visible
798 : * and presult->all_frozen after determining whether or not to
799 : * opportunistically freeze, to indicate if the VM bits can be set. They are
800 : * always set to false when the HEAP_PAGE_PRUNE_FREEZE option is not passed,
801 : * because at the moment only callers that also freeze need that information.
802 : *
803 : * presult contains output parameters needed by callers, such as the number of
804 : * tuples removed and the offsets of dead items on the page after pruning.
805 : * heap_page_prune_and_freeze() is responsible for initializing it. Required
806 : * by all callers.
807 : *
808 : * off_loc is the offset location required by the caller to use in error
809 : * callback.
810 : *
811 : * new_relfrozen_xid and new_relmin_mxid must be provided by the caller if the
812 : * HEAP_PAGE_PRUNE_FREEZE option is set in params. On entry, they contain the
813 : * oldest XID and multi-XID seen on the relation so far. They will be updated
814 : * with the oldest values present on the page after pruning. After processing
815 : * the whole relation, VACUUM can use these values as the new
816 : * relfrozenxid/relminmxid for the relation.
817 : */
818 : void
819 1039046 : heap_page_prune_and_freeze(PruneFreezeParams *params,
820 : PruneFreezeResult *presult,
821 : OffsetNumber *off_loc,
822 : TransactionId *new_relfrozen_xid,
823 : MultiXactId *new_relmin_mxid)
824 : {
825 1039046 : Buffer buffer = params->buffer;
826 1039046 : Page page = BufferGetPage(buffer);
827 : PruneState prstate;
828 : bool do_freeze;
829 : bool do_prune;
830 : bool do_hint_prune;
831 : bool did_tuple_hint_fpi;
832 1039046 : int64 fpi_before = pgWalUsage.wal_fpi;
833 :
834 : /* Initialize prstate */
835 1039046 : prune_freeze_setup(params,
836 : new_relfrozen_xid, new_relmin_mxid,
837 : presult, &prstate);
838 :
839 : /*
840 : * Examine all line pointers and tuple visibility information to determine
841 : * which line pointers should change state and which tuples may be frozen.
842 : * Prepare queue of state changes to later be executed in a critical
843 : * section.
844 : */
845 1039046 : prune_freeze_plan(RelationGetRelid(params->relation),
846 : buffer, &prstate, off_loc);
847 :
848 : /*
849 : * If checksums are enabled, calling heap_prune_satisfies_vacuum() while
850 : * checking tuple visibility information in prune_freeze_plan() may have
851 : * caused an FPI to be emitted.
852 : */
853 1039046 : did_tuple_hint_fpi = fpi_before != pgWalUsage.wal_fpi;
854 :
855 3082696 : do_prune = prstate.nredirected > 0 ||
856 1972436 : prstate.ndead > 0 ||
857 933390 : prstate.nunused > 0;
858 :
859 : /*
860 : * Even if we don't prune anything, if we found a new value for the
861 : * pd_prune_xid field or the page was marked full, we will update the hint
862 : * bit.
863 : */
864 1971884 : do_hint_prune = ((PageHeader) page)->pd_prune_xid != prstate.new_prune_xid ||
865 932838 : PageIsFull(page);
866 :
867 : /*
868 : * Decide if we want to go ahead with freezing according to the freeze
869 : * plans we prepared, or not.
870 : */
871 1039046 : do_freeze = heap_page_will_freeze(params->relation, buffer,
872 : did_tuple_hint_fpi,
873 : do_prune,
874 : do_hint_prune,
875 : &prstate);
876 :
877 : /*
878 : * While scanning the line pointers, we did not clear
879 : * all_visible/all_frozen when encountering LP_DEAD items because we
880 : * wanted the decision whether or not to freeze the page to be unaffected
881 : * by the short-term presence of LP_DEAD items. These LP_DEAD items are
882 : * effectively assumed to be LP_UNUSED items in the making. It doesn't
883 : * matter which vacuum heap pass (initial pass or final pass) ends up
884 : * setting the page all-frozen, as long as the ongoing VACUUM does it.
885 : *
886 : * Now that we finished determining whether or not to freeze the page,
887 : * update all_visible and all_frozen so that they reflect the true state
888 : * of the page for setting PD_ALL_VISIBLE and VM bits.
889 : */
890 1039046 : if (prstate.lpdead_items > 0)
891 107006 : prstate.all_visible = prstate.all_frozen = false;
892 :
893 : Assert(!prstate.all_frozen || prstate.all_visible);
894 :
895 : /* Any error while applying the changes is critical */
896 1039046 : START_CRIT_SECTION();
897 :
898 1039046 : if (do_hint_prune)
899 : {
900 : /*
901 : * Update the page's pd_prune_xid field to either zero, or the lowest
902 : * XID of any soon-prunable tuple.
903 : */
904 106380 : ((PageHeader) page)->pd_prune_xid = prstate.new_prune_xid;
905 :
906 : /*
907 : * Also clear the "page is full" flag, since there's no point in
908 : * repeating the prune/defrag process until something else happens to
909 : * the page.
910 : */
911 106380 : PageClearFull(page);
912 :
913 : /*
914 : * If that's all we had to do to the page, this is a non-WAL-logged
915 : * hint. If we are going to freeze or prune the page, we will mark
916 : * the buffer dirty below.
917 : */
918 106380 : if (!do_freeze && !do_prune)
919 368 : MarkBufferDirtyHint(buffer, true);
920 : }
921 :
922 1039046 : if (do_prune || do_freeze)
923 : {
924 : /* Apply the planned item changes and repair page fragmentation. */
925 148962 : if (do_prune)
926 : {
927 106424 : heap_page_prune_execute(buffer, false,
928 : prstate.redirected, prstate.nredirected,
929 : prstate.nowdead, prstate.ndead,
930 : prstate.nowunused, prstate.nunused);
931 : }
932 :
933 148962 : if (do_freeze)
934 46110 : heap_freeze_prepared_tuples(buffer, prstate.frozen, prstate.nfrozen);
935 :
936 148962 : MarkBufferDirty(buffer);
937 :
938 : /*
939 : * Emit a WAL XLOG_HEAP2_PRUNE* record showing what we did
940 : */
941 148962 : if (RelationNeedsWAL(params->relation))
942 : {
943 : /*
944 : * The snapshotConflictHorizon for the whole record should be the
945 : * most conservative of all the horizons calculated for any of the
946 : * possible modifications. If this record will prune tuples, any
947 : * transactions on the standby older than the youngest xmax of the
948 : * most recently removed tuple this record will prune will
949 : * conflict. If this record will freeze tuples, any transactions
950 : * on the standby with xids older than the youngest tuple this
951 : * record will freeze will conflict.
952 : */
953 : TransactionId conflict_xid;
954 :
955 147208 : if (TransactionIdFollows(prstate.frz_conflict_horizon,
956 : prstate.latest_xid_removed))
957 43260 : conflict_xid = prstate.frz_conflict_horizon;
958 : else
959 103948 : conflict_xid = prstate.latest_xid_removed;
960 :
961 147208 : log_heap_prune_and_freeze(params->relation, buffer,
962 : InvalidBuffer, /* vmbuffer */
963 : 0, /* vmflags */
964 : conflict_xid,
965 : true, params->reason,
966 : prstate.frozen, prstate.nfrozen,
967 : prstate.redirected, prstate.nredirected,
968 : prstate.nowdead, prstate.ndead,
969 : prstate.nowunused, prstate.nunused);
970 : }
971 : }
972 :
973 1039046 : END_CRIT_SECTION();
974 :
975 : /* Copy information back for caller */
976 1039046 : presult->ndeleted = prstate.ndeleted;
977 1039046 : presult->nnewlpdead = prstate.ndead;
978 1039046 : presult->nfrozen = prstate.nfrozen;
979 1039046 : presult->live_tuples = prstate.live_tuples;
980 1039046 : presult->recently_dead_tuples = prstate.recently_dead_tuples;
981 1039046 : presult->all_visible = prstate.all_visible;
982 1039046 : presult->all_frozen = prstate.all_frozen;
983 1039046 : presult->hastup = prstate.hastup;
984 :
985 : /*
986 : * For callers planning to update the visibility map, the conflict horizon
987 : * for that record must be the newest xmin on the page. However, if the
988 : * page is completely frozen, there can be no conflict and the
989 : * vm_conflict_horizon should remain InvalidTransactionId. This includes
990 : * the case that we just froze all the tuples; the prune-freeze record
991 : * included the conflict XID already so the caller doesn't need it.
992 : */
993 1039046 : if (presult->all_frozen)
994 457928 : presult->vm_conflict_horizon = InvalidTransactionId;
995 : else
996 581118 : presult->vm_conflict_horizon = prstate.visibility_cutoff_xid;
997 :
998 1039046 : presult->lpdead_items = prstate.lpdead_items;
999 : /* the presult->deadoffsets array was already filled in */
1000 :
1001 1039046 : if (prstate.attempt_freeze)
1002 : {
1003 954034 : if (presult->nfrozen > 0)
1004 : {
1005 46110 : *new_relfrozen_xid = prstate.pagefrz.FreezePageRelfrozenXid;
1006 46110 : *new_relmin_mxid = prstate.pagefrz.FreezePageRelminMxid;
1007 : }
1008 : else
1009 : {
1010 907924 : *new_relfrozen_xid = prstate.pagefrz.NoFreezePageRelfrozenXid;
1011 907924 : *new_relmin_mxid = prstate.pagefrz.NoFreezePageRelminMxid;
1012 : }
1013 : }
1014 1039046 : }
1015 :
1016 :
1017 : /*
1018 : * Perform visibility checks for heap pruning.
1019 : */
1020 : static HTSV_Result
1021 49320470 : heap_prune_satisfies_vacuum(PruneState *prstate, HeapTuple tup, Buffer buffer)
1022 : {
1023 : HTSV_Result res;
1024 : TransactionId dead_after;
1025 :
1026 49320470 : res = HeapTupleSatisfiesVacuumHorizon(tup, buffer, &dead_after);
1027 :
1028 49320470 : if (res != HEAPTUPLE_RECENTLY_DEAD)
1029 45991674 : return res;
1030 :
1031 : /*
1032 : * For VACUUM, we must be sure to prune tuples with xmax older than
1033 : * OldestXmin -- a visibility cutoff determined at the beginning of
1034 : * vacuuming the relation. OldestXmin is used for freezing determination
1035 : * and we cannot freeze dead tuples' xmaxes.
1036 : */
1037 3328796 : if (prstate->cutoffs &&
1038 1765660 : TransactionIdIsValid(prstate->cutoffs->OldestXmin) &&
1039 1765660 : NormalTransactionIdPrecedes(dead_after, prstate->cutoffs->OldestXmin))
1040 1272102 : return HEAPTUPLE_DEAD;
1041 :
1042 : /*
1043 : * Determine whether or not the tuple is considered dead when compared
1044 : * with the provided GlobalVisState. On-access pruning does not provide
1045 : * VacuumCutoffs. And for vacuum, even if the tuple's xmax is not older
1046 : * than OldestXmin, GlobalVisTestIsRemovableXid() could find the row dead
1047 : * if the GlobalVisState has been updated since the beginning of vacuuming
1048 : * the relation.
1049 : */
1050 2056694 : if (GlobalVisTestIsRemovableXid(prstate->vistest, dead_after))
1051 1498428 : return HEAPTUPLE_DEAD;
1052 :
1053 558266 : return res;
1054 : }
1055 :
1056 :
1057 : /*
1058 : * Pruning calculates tuple visibility once and saves the results in an array
1059 : * of int8. See PruneState.htsv for details. This helper function is meant
1060 : * to guard against examining visibility status array members which have not
1061 : * yet been computed.
1062 : */
1063 : static inline HTSV_Result
1064 49292610 : htsv_get_valid_status(int status)
1065 : {
1066 : Assert(status >= HEAPTUPLE_DEAD &&
1067 : status <= HEAPTUPLE_DELETE_IN_PROGRESS);
1068 49292610 : return (HTSV_Result) status;
1069 : }
1070 :
1071 : /*
1072 : * Prune specified line pointer or a HOT chain originating at line pointer.
1073 : *
1074 : * Tuple visibility information is provided in prstate->htsv.
1075 : *
1076 : * If the item is an index-referenced tuple (i.e. not a heap-only tuple),
1077 : * the HOT chain is pruned by removing all DEAD tuples at the start of the HOT
1078 : * chain. We also prune any RECENTLY_DEAD tuples preceding a DEAD tuple.
1079 : * This is OK because a RECENTLY_DEAD tuple preceding a DEAD tuple is really
1080 : * DEAD, our visibility test is just too coarse to detect it.
1081 : *
1082 : * Pruning must never leave behind a DEAD tuple that still has tuple storage.
1083 : * VACUUM isn't prepared to deal with that case.
1084 : *
1085 : * The root line pointer is redirected to the tuple immediately after the
1086 : * latest DEAD tuple. If all tuples in the chain are DEAD, the root line
1087 : * pointer is marked LP_DEAD. (This includes the case of a DEAD simple
1088 : * tuple, which we treat as a chain of length 1.)
1089 : *
1090 : * We don't actually change the page here. We just add entries to the arrays in
1091 : * prstate showing the changes to be made. Items to be redirected are added
1092 : * to the redirected[] array (two entries per redirection); items to be set to
1093 : * LP_DEAD state are added to nowdead[]; and items to be set to LP_UNUSED
1094 : * state are added to nowunused[]. We perform bookkeeping of live tuples,
1095 : * visibility etc. based on what the page will look like after the changes
1096 : * applied. All that bookkeeping is performed in the heap_prune_record_*()
1097 : * subroutines. The division of labor is that heap_prune_chain() decides the
1098 : * fate of each tuple, ie. whether it's going to be removed, redirected or
1099 : * left unchanged, and the heap_prune_record_*() subroutines update PruneState
1100 : * based on that outcome.
1101 : */
1102 : static void
1103 49072516 : heap_prune_chain(Page page, BlockNumber blockno, OffsetNumber maxoff,
1104 : OffsetNumber rootoffnum, PruneState *prstate)
1105 : {
1106 49072516 : TransactionId priorXmax = InvalidTransactionId;
1107 : ItemId rootlp;
1108 : OffsetNumber offnum;
1109 : OffsetNumber chainitems[MaxHeapTuplesPerPage];
1110 :
1111 : /*
1112 : * After traversing the HOT chain, ndeadchain is the index in chainitems
1113 : * of the first live successor after the last dead item.
1114 : */
1115 49072516 : int ndeadchain = 0,
1116 49072516 : nchain = 0;
1117 :
1118 49072516 : rootlp = PageGetItemId(page, rootoffnum);
1119 :
1120 : /* Start from the root tuple */
1121 49072516 : offnum = rootoffnum;
1122 :
1123 : /* while not end of the chain */
1124 : for (;;)
1125 885188 : {
1126 : HeapTupleHeader htup;
1127 : ItemId lp;
1128 :
1129 : /* Sanity check (pure paranoia) */
1130 49957704 : if (offnum < FirstOffsetNumber)
1131 0 : break;
1132 :
1133 : /*
1134 : * An offset past the end of page's line pointer array is possible
1135 : * when the array was truncated (original item must have been unused)
1136 : */
1137 49957704 : if (offnum > maxoff)
1138 0 : break;
1139 :
1140 : /* If item is already processed, stop --- it must not be same chain */
1141 49957704 : if (prstate->processed[offnum])
1142 0 : break;
1143 :
1144 49957704 : lp = PageGetItemId(page, offnum);
1145 :
1146 : /*
1147 : * Unused item obviously isn't part of the chain. Likewise, a dead
1148 : * line pointer can't be part of the chain. Both of those cases were
1149 : * already marked as processed.
1150 : */
1151 : Assert(ItemIdIsUsed(lp));
1152 : Assert(!ItemIdIsDead(lp));
1153 :
1154 : /*
1155 : * If we are looking at the redirected root line pointer, jump to the
1156 : * first normal tuple in the chain. If we find a redirect somewhere
1157 : * else, stop --- it must not be same chain.
1158 : */
1159 49957704 : if (ItemIdIsRedirected(lp))
1160 : {
1161 665094 : if (nchain > 0)
1162 0 : break; /* not at start of chain */
1163 665094 : chainitems[nchain++] = offnum;
1164 665094 : offnum = ItemIdGetRedirect(rootlp);
1165 665094 : continue;
1166 : }
1167 :
1168 : Assert(ItemIdIsNormal(lp));
1169 :
1170 49292610 : htup = (HeapTupleHeader) PageGetItem(page, lp);
1171 :
1172 : /*
1173 : * Check the tuple XMIN against prior XMAX, if any
1174 : */
1175 49512704 : if (TransactionIdIsValid(priorXmax) &&
1176 220094 : !TransactionIdEquals(HeapTupleHeaderGetXmin(htup), priorXmax))
1177 0 : break;
1178 :
1179 : /*
1180 : * OK, this tuple is indeed a member of the chain.
1181 : */
1182 49292610 : chainitems[nchain++] = offnum;
1183 :
1184 49292610 : switch (htsv_get_valid_status(prstate->htsv[offnum]))
1185 : {
1186 2853570 : case HEAPTUPLE_DEAD:
1187 :
1188 : /* Remember the last DEAD tuple seen */
1189 2853570 : ndeadchain = nchain;
1190 2853570 : HeapTupleHeaderAdvanceConflictHorizon(htup,
1191 : &prstate->latest_xid_removed);
1192 : /* Advance to next chain member */
1193 2853570 : break;
1194 :
1195 558266 : case HEAPTUPLE_RECENTLY_DEAD:
1196 :
1197 : /*
1198 : * We don't need to advance the conflict horizon for
1199 : * RECENTLY_DEAD tuples, even if we are removing them. This
1200 : * is because we only remove RECENTLY_DEAD tuples if they
1201 : * precede a DEAD tuple, and the DEAD tuple must have been
1202 : * inserted by a newer transaction than the RECENTLY_DEAD
1203 : * tuple by virtue of being later in the chain. We will have
1204 : * advanced the conflict horizon for the DEAD tuple.
1205 : */
1206 :
1207 : /*
1208 : * Advance past RECENTLY_DEAD tuples just in case there's a
1209 : * DEAD one after them. We have to make sure that we don't
1210 : * miss any DEAD tuples, since DEAD tuples that still have
1211 : * tuple storage after pruning will confuse VACUUM.
1212 : */
1213 558266 : break;
1214 :
1215 45880774 : case HEAPTUPLE_DELETE_IN_PROGRESS:
1216 : case HEAPTUPLE_LIVE:
1217 : case HEAPTUPLE_INSERT_IN_PROGRESS:
1218 45880774 : goto process_chain;
1219 :
1220 0 : default:
1221 0 : elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result");
1222 : goto process_chain;
1223 : }
1224 :
1225 : /*
1226 : * If the tuple is not HOT-updated, then we are at the end of this
1227 : * HOT-update chain.
1228 : */
1229 3411836 : if (!HeapTupleHeaderIsHotUpdated(htup))
1230 3191742 : goto process_chain;
1231 :
1232 : /* HOT implies it can't have moved to different partition */
1233 : Assert(!HeapTupleHeaderIndicatesMovedPartitions(htup));
1234 :
1235 : /*
1236 : * Advance to next chain member.
1237 : */
1238 : Assert(ItemPointerGetBlockNumber(&htup->t_ctid) == blockno);
1239 220094 : offnum = ItemPointerGetOffsetNumber(&htup->t_ctid);
1240 220094 : priorXmax = HeapTupleHeaderGetUpdateXid(htup);
1241 : }
1242 :
1243 0 : if (ItemIdIsRedirected(rootlp) && nchain < 2)
1244 : {
1245 : /*
1246 : * We found a redirect item that doesn't point to a valid follow-on
1247 : * item. This can happen if the loop in heap_page_prune_and_freeze()
1248 : * caused us to visit the dead successor of a redirect item before
1249 : * visiting the redirect item. We can clean up by setting the
1250 : * redirect item to LP_DEAD state or LP_UNUSED if the caller
1251 : * indicated.
1252 : */
1253 0 : heap_prune_record_dead_or_unused(prstate, rootoffnum, false);
1254 0 : return;
1255 : }
1256 :
1257 0 : process_chain:
1258 :
1259 49072516 : if (ndeadchain == 0)
1260 : {
1261 : /*
1262 : * No DEAD tuple was found, so the chain is entirely composed of
1263 : * normal, unchanged tuples. Leave it alone.
1264 : */
1265 46293112 : int i = 0;
1266 :
1267 46293112 : if (ItemIdIsRedirected(rootlp))
1268 : {
1269 630518 : heap_prune_record_unchanged_lp_redirect(prstate, rootoffnum);
1270 630518 : i++;
1271 : }
1272 92594672 : for (; i < nchain; i++)
1273 46301560 : heap_prune_record_unchanged_lp_normal(page, prstate, chainitems[i]);
1274 : }
1275 2779404 : else if (ndeadchain == nchain)
1276 : {
1277 : /*
1278 : * The entire chain is dead. Mark the root line pointer LP_DEAD, and
1279 : * fully remove the other tuples in the chain.
1280 : */
1281 2647046 : heap_prune_record_dead_or_unused(prstate, rootoffnum, ItemIdIsNormal(rootlp));
1282 2717070 : for (int i = 1; i < nchain; i++)
1283 70024 : heap_prune_record_unused(prstate, chainitems[i], true);
1284 : }
1285 : else
1286 : {
1287 : /*
1288 : * We found a DEAD tuple in the chain. Redirect the root line pointer
1289 : * to the first non-DEAD tuple, and mark as unused each intermediate
1290 : * item that we are able to remove from the chain.
1291 : */
1292 132358 : heap_prune_record_redirect(prstate, rootoffnum, chainitems[ndeadchain],
1293 132358 : ItemIdIsNormal(rootlp));
1294 171076 : for (int i = 1; i < ndeadchain; i++)
1295 38718 : heap_prune_record_unused(prstate, chainitems[i], true);
1296 :
1297 : /* the rest of tuples in the chain are normal, unchanged tuples */
1298 269838 : for (int i = ndeadchain; i < nchain; i++)
1299 137480 : heap_prune_record_unchanged_lp_normal(page, prstate, chainitems[i]);
1300 : }
1301 : }
1302 :
1303 : /* Record lowest soon-prunable XID */
1304 : static void
1305 11436896 : heap_prune_record_prunable(PruneState *prstate, TransactionId xid)
1306 : {
1307 : /*
1308 : * This should exactly match the PageSetPrunable macro. We can't store
1309 : * directly into the page header yet, so we update working state.
1310 : */
1311 : Assert(TransactionIdIsNormal(xid));
1312 22423368 : if (!TransactionIdIsValid(prstate->new_prune_xid) ||
1313 10986472 : TransactionIdPrecedes(xid, prstate->new_prune_xid))
1314 452852 : prstate->new_prune_xid = xid;
1315 11436896 : }
1316 :
1317 : /* Record line pointer to be redirected */
1318 : static void
1319 132358 : heap_prune_record_redirect(PruneState *prstate,
1320 : OffsetNumber offnum, OffsetNumber rdoffnum,
1321 : bool was_normal)
1322 : {
1323 : Assert(!prstate->processed[offnum]);
1324 132358 : prstate->processed[offnum] = true;
1325 :
1326 : /*
1327 : * Do not mark the redirect target here. It needs to be counted
1328 : * separately as an unchanged tuple.
1329 : */
1330 :
1331 : Assert(prstate->nredirected < MaxHeapTuplesPerPage);
1332 132358 : prstate->redirected[prstate->nredirected * 2] = offnum;
1333 132358 : prstate->redirected[prstate->nredirected * 2 + 1] = rdoffnum;
1334 :
1335 132358 : prstate->nredirected++;
1336 :
1337 : /*
1338 : * If the root entry had been a normal tuple, we are deleting it, so count
1339 : * it in the result. But changing a redirect (even to DEAD state) doesn't
1340 : * count.
1341 : */
1342 132358 : if (was_normal)
1343 116706 : prstate->ndeleted++;
1344 :
1345 132358 : prstate->hastup = true;
1346 132358 : }
1347 :
1348 : /* Record line pointer to be marked dead */
1349 : static void
1350 2576914 : heap_prune_record_dead(PruneState *prstate, OffsetNumber offnum,
1351 : bool was_normal)
1352 : {
1353 : Assert(!prstate->processed[offnum]);
1354 2576914 : prstate->processed[offnum] = true;
1355 :
1356 : Assert(prstate->ndead < MaxHeapTuplesPerPage);
1357 2576914 : prstate->nowdead[prstate->ndead] = offnum;
1358 2576914 : prstate->ndead++;
1359 :
1360 : /*
1361 : * Deliberately delay unsetting all_visible and all_frozen until later
1362 : * during pruning. Removable dead tuples shouldn't preclude freezing the
1363 : * page.
1364 : */
1365 :
1366 : /* Record the dead offset for vacuum */
1367 2576914 : prstate->deadoffsets[prstate->lpdead_items++] = offnum;
1368 :
1369 : /*
1370 : * If the root entry had been a normal tuple, we are deleting it, so count
1371 : * it in the result. But changing a redirect (even to DEAD state) doesn't
1372 : * count.
1373 : */
1374 2576914 : if (was_normal)
1375 2557990 : prstate->ndeleted++;
1376 2576914 : }
1377 :
1378 : /*
1379 : * Depending on whether or not the caller set mark_unused_now to true, record that a
1380 : * line pointer should be marked LP_DEAD or LP_UNUSED. There are other cases in
1381 : * which we will mark line pointers LP_UNUSED, but we will not mark line
1382 : * pointers LP_DEAD if mark_unused_now is true.
1383 : */
1384 : static void
1385 2647046 : heap_prune_record_dead_or_unused(PruneState *prstate, OffsetNumber offnum,
1386 : bool was_normal)
1387 : {
1388 : /*
1389 : * If the caller set mark_unused_now to true, we can remove dead tuples
1390 : * during pruning instead of marking their line pointers dead. Set this
1391 : * tuple's line pointer LP_UNUSED. We hint that this option is less
1392 : * likely.
1393 : */
1394 2647046 : if (unlikely(prstate->mark_unused_now))
1395 70132 : heap_prune_record_unused(prstate, offnum, was_normal);
1396 : else
1397 2576914 : heap_prune_record_dead(prstate, offnum, was_normal);
1398 2647046 : }
1399 :
1400 : /* Record line pointer to be marked unused */
1401 : static void
1402 183150 : heap_prune_record_unused(PruneState *prstate, OffsetNumber offnum, bool was_normal)
1403 : {
1404 : Assert(!prstate->processed[offnum]);
1405 183150 : prstate->processed[offnum] = true;
1406 :
1407 : Assert(prstate->nunused < MaxHeapTuplesPerPage);
1408 183150 : prstate->nowunused[prstate->nunused] = offnum;
1409 183150 : prstate->nunused++;
1410 :
1411 : /*
1412 : * If the root entry had been a normal tuple, we are deleting it, so count
1413 : * it in the result. But changing a redirect (even to DEAD state) doesn't
1414 : * count.
1415 : */
1416 183150 : if (was_normal)
1417 183150 : prstate->ndeleted++;
1418 183150 : }
1419 :
1420 : /*
1421 : * Record an unused line pointer that is left unchanged.
1422 : */
1423 : static void
1424 642676 : heap_prune_record_unchanged_lp_unused(Page page, PruneState *prstate, OffsetNumber offnum)
1425 : {
1426 : Assert(!prstate->processed[offnum]);
1427 642676 : prstate->processed[offnum] = true;
1428 642676 : }
1429 :
1430 : /*
1431 : * Record line pointer that is left unchanged. We consider freezing it, and
1432 : * update bookkeeping of tuple counts and page visibility.
1433 : */
1434 : static void
1435 46462624 : heap_prune_record_unchanged_lp_normal(Page page, PruneState *prstate, OffsetNumber offnum)
1436 : {
1437 : HeapTupleHeader htup;
1438 :
1439 : Assert(!prstate->processed[offnum]);
1440 46462624 : prstate->processed[offnum] = true;
1441 :
1442 46462624 : prstate->hastup = true; /* the page is not empty */
1443 :
1444 : /*
1445 : * The criteria for counting a tuple as live in this block need to match
1446 : * what analyze.c's acquire_sample_rows() does, otherwise VACUUM and
1447 : * ANALYZE may produce wildly different reltuples values, e.g. when there
1448 : * are many recently-dead tuples.
1449 : *
1450 : * The logic here is a bit simpler than acquire_sample_rows(), as VACUUM
1451 : * can't run inside a transaction block, which makes some cases impossible
1452 : * (e.g. in-progress insert from the same transaction).
1453 : *
1454 : * HEAPTUPLE_DEAD are handled by the other heap_prune_record_*()
1455 : * subroutines. They don't count dead items like acquire_sample_rows()
1456 : * does, because we assume that all dead items will become LP_UNUSED
1457 : * before VACUUM finishes. This difference is only superficial. VACUUM
1458 : * effectively agrees with ANALYZE about DEAD items, in the end. VACUUM
1459 : * won't remember LP_DEAD items, but only because they're not supposed to
1460 : * be left behind when it is done. (Cases where we bypass index vacuuming
1461 : * will violate this optimistic assumption, but the overall impact of that
1462 : * should be negligible.)
1463 : */
1464 46462624 : htup = (HeapTupleHeader) PageGetItem(page, PageGetItemId(page, offnum));
1465 :
1466 46462624 : switch (prstate->htsv[offnum])
1467 : {
1468 34900302 : case HEAPTUPLE_LIVE:
1469 :
1470 : /*
1471 : * Count it as live. Not only is this natural, but it's also what
1472 : * acquire_sample_rows() does.
1473 : */
1474 34900302 : prstate->live_tuples++;
1475 :
1476 : /*
1477 : * Is the tuple definitely visible to all transactions?
1478 : *
1479 : * NB: Like with per-tuple hint bits, we can't set the
1480 : * PD_ALL_VISIBLE flag if the inserter committed asynchronously.
1481 : * See SetHintBits for more info. Check that the tuple is hinted
1482 : * xmin-committed because of that.
1483 : */
1484 34900302 : if (prstate->all_visible)
1485 : {
1486 : TransactionId xmin;
1487 :
1488 27256758 : if (!HeapTupleHeaderXminCommitted(htup))
1489 : {
1490 536 : prstate->all_visible = false;
1491 536 : prstate->all_frozen = false;
1492 536 : break;
1493 : }
1494 :
1495 : /*
1496 : * The inserter definitely committed. But is it old enough
1497 : * that everyone sees it as committed? A FrozenTransactionId
1498 : * is seen as committed to everyone. Otherwise, we check if
1499 : * there is a snapshot that considers this xid to still be
1500 : * running, and if so, we don't consider the page all-visible.
1501 : */
1502 27256222 : xmin = HeapTupleHeaderGetXmin(htup);
1503 :
1504 : /*
1505 : * For now always use prstate->cutoffs for this test, because
1506 : * we only update 'all_visible' and 'all_frozen' when freezing
1507 : * is requested. We could use GlobalVisTestIsRemovableXid
1508 : * instead, if a non-freezing caller wanted to set the VM bit.
1509 : */
1510 : Assert(prstate->cutoffs);
1511 27256222 : if (!TransactionIdPrecedes(xmin, prstate->cutoffs->OldestXmin))
1512 : {
1513 5806 : prstate->all_visible = false;
1514 5806 : prstate->all_frozen = false;
1515 5806 : break;
1516 : }
1517 :
1518 : /* Track newest xmin on page. */
1519 27250416 : if (TransactionIdFollows(xmin, prstate->visibility_cutoff_xid) &&
1520 : TransactionIdIsNormal(xmin))
1521 216464 : prstate->visibility_cutoff_xid = xmin;
1522 : }
1523 34893960 : break;
1524 :
1525 558266 : case HEAPTUPLE_RECENTLY_DEAD:
1526 558266 : prstate->recently_dead_tuples++;
1527 558266 : prstate->all_visible = false;
1528 558266 : prstate->all_frozen = false;
1529 :
1530 : /*
1531 : * This tuple will soon become DEAD. Update the hint field so
1532 : * that the page is reconsidered for pruning in future.
1533 : */
1534 558266 : heap_prune_record_prunable(prstate,
1535 : HeapTupleHeaderGetUpdateXid(htup));
1536 558266 : break;
1537 :
1538 125426 : case HEAPTUPLE_INSERT_IN_PROGRESS:
1539 :
1540 : /*
1541 : * We do not count these rows as live, because we expect the
1542 : * inserting transaction to update the counters at commit, and we
1543 : * assume that will happen only after we report our results. This
1544 : * assumption is a bit shaky, but it is what acquire_sample_rows()
1545 : * does, so be consistent.
1546 : */
1547 125426 : prstate->all_visible = false;
1548 125426 : prstate->all_frozen = false;
1549 :
1550 : /*
1551 : * If we wanted to optimize for aborts, we might consider marking
1552 : * the page prunable when we see INSERT_IN_PROGRESS. But we
1553 : * don't. See related decisions about when to mark the page
1554 : * prunable in heapam.c.
1555 : */
1556 125426 : break;
1557 :
1558 10878630 : case HEAPTUPLE_DELETE_IN_PROGRESS:
1559 :
1560 : /*
1561 : * This an expected case during concurrent vacuum. Count such
1562 : * rows as live. As above, we assume the deleting transaction
1563 : * will commit and update the counters after we report.
1564 : */
1565 10878630 : prstate->live_tuples++;
1566 10878630 : prstate->all_visible = false;
1567 10878630 : prstate->all_frozen = false;
1568 :
1569 : /*
1570 : * This tuple may soon become DEAD. Update the hint field so that
1571 : * the page is reconsidered for pruning in future.
1572 : */
1573 10878630 : heap_prune_record_prunable(prstate,
1574 : HeapTupleHeaderGetUpdateXid(htup));
1575 10878630 : break;
1576 :
1577 0 : default:
1578 :
1579 : /*
1580 : * DEAD tuples should've been passed to heap_prune_record_dead()
1581 : * or heap_prune_record_unused() instead.
1582 : */
1583 0 : elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result %d",
1584 : prstate->htsv[offnum]);
1585 : break;
1586 : }
1587 :
1588 : /* Consider freezing any normal tuples which will not be removed */
1589 46462624 : if (prstate->attempt_freeze)
1590 : {
1591 : bool totally_frozen;
1592 :
1593 43485568 : if ((heap_prepare_freeze_tuple(htup,
1594 43485568 : prstate->cutoffs,
1595 : &prstate->pagefrz,
1596 43485568 : &prstate->frozen[prstate->nfrozen],
1597 : &totally_frozen)))
1598 : {
1599 : /* Save prepared freeze plan for later */
1600 4116250 : prstate->frozen[prstate->nfrozen++].offset = offnum;
1601 : }
1602 :
1603 : /*
1604 : * If any tuple isn't either totally frozen already or eligible to
1605 : * become totally frozen (according to its freeze plan), then the page
1606 : * definitely cannot be set all-frozen in the visibility map later on.
1607 : */
1608 43485568 : if (!totally_frozen)
1609 12031334 : prstate->all_frozen = false;
1610 : }
1611 46462624 : }
1612 :
1613 :
1614 : /*
1615 : * Record line pointer that was already LP_DEAD and is left unchanged.
1616 : */
1617 : static void
1618 1977078 : heap_prune_record_unchanged_lp_dead(Page page, PruneState *prstate, OffsetNumber offnum)
1619 : {
1620 : Assert(!prstate->processed[offnum]);
1621 1977078 : prstate->processed[offnum] = true;
1622 :
1623 : /*
1624 : * Deliberately don't set hastup for LP_DEAD items. We make the soft
1625 : * assumption that any LP_DEAD items encountered here will become
1626 : * LP_UNUSED later on, before count_nondeletable_pages is reached. If we
1627 : * don't make this assumption then rel truncation will only happen every
1628 : * other VACUUM, at most. Besides, VACUUM must treat
1629 : * hastup/nonempty_pages as provisional no matter how LP_DEAD items are
1630 : * handled (handled here, or handled later on).
1631 : *
1632 : * Similarly, don't unset all_visible and all_frozen until later, at the
1633 : * end of heap_page_prune_and_freeze(). This will allow us to attempt to
1634 : * freeze the page after pruning. As long as we unset it before updating
1635 : * the visibility map, this will be correct.
1636 : */
1637 :
1638 : /* Record the dead offset for vacuum */
1639 1977078 : prstate->deadoffsets[prstate->lpdead_items++] = offnum;
1640 1977078 : }
1641 :
1642 : /*
1643 : * Record LP_REDIRECT that is left unchanged.
1644 : */
1645 : static void
1646 630518 : heap_prune_record_unchanged_lp_redirect(PruneState *prstate, OffsetNumber offnum)
1647 : {
1648 : /*
1649 : * A redirect line pointer doesn't count as a live tuple.
1650 : *
1651 : * If we leave a redirect line pointer in place, there will be another
1652 : * tuple on the page that it points to. We will do the bookkeeping for
1653 : * that separately. So we have nothing to do here, except remember that
1654 : * we processed this item.
1655 : */
1656 : Assert(!prstate->processed[offnum]);
1657 630518 : prstate->processed[offnum] = true;
1658 630518 : }
1659 :
1660 : /*
1661 : * Perform the actual page changes needed by heap_page_prune_and_freeze().
1662 : *
1663 : * If 'lp_truncate_only' is set, we are merely marking LP_DEAD line pointers
1664 : * as unused, not redirecting or removing anything else. The
1665 : * PageRepairFragmentation() call is skipped in that case.
1666 : *
1667 : * If 'lp_truncate_only' is not set, the caller must hold a cleanup lock on
1668 : * the buffer. If it is set, an ordinary exclusive lock suffices.
1669 : */
1670 : void
1671 126566 : heap_page_prune_execute(Buffer buffer, bool lp_truncate_only,
1672 : OffsetNumber *redirected, int nredirected,
1673 : OffsetNumber *nowdead, int ndead,
1674 : OffsetNumber *nowunused, int nunused)
1675 : {
1676 126566 : Page page = BufferGetPage(buffer);
1677 : OffsetNumber *offnum;
1678 : HeapTupleHeader htup PG_USED_FOR_ASSERTS_ONLY;
1679 :
1680 : /* Shouldn't be called unless there's something to do */
1681 : Assert(nredirected > 0 || ndead > 0 || nunused > 0);
1682 :
1683 : /* If 'lp_truncate_only', we can only remove already-dead line pointers */
1684 : Assert(!lp_truncate_only || (nredirected == 0 && ndead == 0));
1685 :
1686 : /* Update all redirected line pointers */
1687 126566 : offnum = redirected;
1688 296452 : for (int i = 0; i < nredirected; i++)
1689 : {
1690 169886 : OffsetNumber fromoff = *offnum++;
1691 169886 : OffsetNumber tooff = *offnum++;
1692 169886 : ItemId fromlp = PageGetItemId(page, fromoff);
1693 : ItemId tolp PG_USED_FOR_ASSERTS_ONLY;
1694 :
1695 : #ifdef USE_ASSERT_CHECKING
1696 :
1697 : /*
1698 : * Any existing item that we set as an LP_REDIRECT (any 'from' item)
1699 : * must be the first item from a HOT chain. If the item has tuple
1700 : * storage then it can't be a heap-only tuple. Otherwise we are just
1701 : * maintaining an existing LP_REDIRECT from an existing HOT chain that
1702 : * has been pruned at least once before now.
1703 : */
1704 : if (!ItemIdIsRedirected(fromlp))
1705 : {
1706 : Assert(ItemIdHasStorage(fromlp) && ItemIdIsNormal(fromlp));
1707 :
1708 : htup = (HeapTupleHeader) PageGetItem(page, fromlp);
1709 : Assert(!HeapTupleHeaderIsHeapOnly(htup));
1710 : }
1711 : else
1712 : {
1713 : /* We shouldn't need to redundantly set the redirect */
1714 : Assert(ItemIdGetRedirect(fromlp) != tooff);
1715 : }
1716 :
1717 : /*
1718 : * The item that we're about to set as an LP_REDIRECT (the 'from'
1719 : * item) will point to an existing item (the 'to' item) that is
1720 : * already a heap-only tuple. There can be at most one LP_REDIRECT
1721 : * item per HOT chain.
1722 : *
1723 : * We need to keep around an LP_REDIRECT item (after original
1724 : * non-heap-only root tuple gets pruned away) so that it's always
1725 : * possible for VACUUM to easily figure out what TID to delete from
1726 : * indexes when an entire HOT chain becomes dead. A heap-only tuple
1727 : * can never become LP_DEAD; an LP_REDIRECT item or a regular heap
1728 : * tuple can.
1729 : *
1730 : * This check may miss problems, e.g. the target of a redirect could
1731 : * be marked as unused subsequently. The page_verify_redirects() check
1732 : * below will catch such problems.
1733 : */
1734 : tolp = PageGetItemId(page, tooff);
1735 : Assert(ItemIdHasStorage(tolp) && ItemIdIsNormal(tolp));
1736 : htup = (HeapTupleHeader) PageGetItem(page, tolp);
1737 : Assert(HeapTupleHeaderIsHeapOnly(htup));
1738 : #endif
1739 :
1740 169886 : ItemIdSetRedirect(fromlp, tooff);
1741 : }
1742 :
1743 : /* Update all now-dead line pointers */
1744 126566 : offnum = nowdead;
1745 3249594 : for (int i = 0; i < ndead; i++)
1746 : {
1747 3123028 : OffsetNumber off = *offnum++;
1748 3123028 : ItemId lp = PageGetItemId(page, off);
1749 :
1750 : #ifdef USE_ASSERT_CHECKING
1751 :
1752 : /*
1753 : * An LP_DEAD line pointer must be left behind when the original item
1754 : * (which is dead to everybody) could still be referenced by a TID in
1755 : * an index. This should never be necessary with any individual
1756 : * heap-only tuple item, though. (It's not clear how much of a problem
1757 : * that would be, but there is no reason to allow it.)
1758 : */
1759 : if (ItemIdHasStorage(lp))
1760 : {
1761 : Assert(ItemIdIsNormal(lp));
1762 : htup = (HeapTupleHeader) PageGetItem(page, lp);
1763 : Assert(!HeapTupleHeaderIsHeapOnly(htup));
1764 : }
1765 : else
1766 : {
1767 : /* Whole HOT chain becomes dead */
1768 : Assert(ItemIdIsRedirected(lp));
1769 : }
1770 : #endif
1771 :
1772 3123028 : ItemIdSetDead(lp);
1773 : }
1774 :
1775 : /* Update all now-unused line pointers */
1776 126566 : offnum = nowunused;
1777 746950 : for (int i = 0; i < nunused; i++)
1778 : {
1779 620384 : OffsetNumber off = *offnum++;
1780 620384 : ItemId lp = PageGetItemId(page, off);
1781 :
1782 : #ifdef USE_ASSERT_CHECKING
1783 :
1784 : if (lp_truncate_only)
1785 : {
1786 : /* Setting LP_DEAD to LP_UNUSED in vacuum's second pass */
1787 : Assert(ItemIdIsDead(lp) && !ItemIdHasStorage(lp));
1788 : }
1789 : else
1790 : {
1791 : /*
1792 : * When heap_page_prune_and_freeze() was called, mark_unused_now
1793 : * may have been passed as true, which allows would-be LP_DEAD
1794 : * items to be made LP_UNUSED instead. This is only possible if
1795 : * the relation has no indexes. If there are any dead items, then
1796 : * mark_unused_now was not true and every item being marked
1797 : * LP_UNUSED must refer to a heap-only tuple.
1798 : */
1799 : if (ndead > 0)
1800 : {
1801 : Assert(ItemIdHasStorage(lp) && ItemIdIsNormal(lp));
1802 : htup = (HeapTupleHeader) PageGetItem(page, lp);
1803 : Assert(HeapTupleHeaderIsHeapOnly(htup));
1804 : }
1805 : else
1806 : Assert(ItemIdIsUsed(lp));
1807 : }
1808 :
1809 : #endif
1810 :
1811 620384 : ItemIdSetUnused(lp);
1812 : }
1813 :
1814 126566 : if (lp_truncate_only)
1815 5546 : PageTruncateLinePointerArray(page);
1816 : else
1817 : {
1818 : /*
1819 : * Finally, repair any fragmentation, and update the page's hint bit
1820 : * about whether it has free pointers.
1821 : */
1822 121020 : PageRepairFragmentation(page);
1823 :
1824 : /*
1825 : * Now that the page has been modified, assert that redirect items
1826 : * still point to valid targets.
1827 : */
1828 121020 : page_verify_redirects(page);
1829 : }
1830 126566 : }
1831 :
1832 :
1833 : /*
1834 : * If built with assertions, verify that all LP_REDIRECT items point to a
1835 : * valid item.
1836 : *
1837 : * One way that bugs related to HOT pruning show is redirect items pointing to
1838 : * removed tuples. It's not trivial to reliably check that marking an item
1839 : * unused will not orphan a redirect item during heap_prune_chain() /
1840 : * heap_page_prune_execute(), so we additionally check the whole page after
1841 : * pruning. Without this check such bugs would typically only cause asserts
1842 : * later, potentially well after the corruption has been introduced.
1843 : *
1844 : * Also check comments in heap_page_prune_execute()'s redirection loop.
1845 : */
1846 : static void
1847 121020 : page_verify_redirects(Page page)
1848 : {
1849 : #ifdef USE_ASSERT_CHECKING
1850 : OffsetNumber offnum;
1851 : OffsetNumber maxoff;
1852 :
1853 : maxoff = PageGetMaxOffsetNumber(page);
1854 : for (offnum = FirstOffsetNumber;
1855 : offnum <= maxoff;
1856 : offnum = OffsetNumberNext(offnum))
1857 : {
1858 : ItemId itemid = PageGetItemId(page, offnum);
1859 : OffsetNumber targoff;
1860 : ItemId targitem;
1861 : HeapTupleHeader htup;
1862 :
1863 : if (!ItemIdIsRedirected(itemid))
1864 : continue;
1865 :
1866 : targoff = ItemIdGetRedirect(itemid);
1867 : targitem = PageGetItemId(page, targoff);
1868 :
1869 : Assert(ItemIdIsUsed(targitem));
1870 : Assert(ItemIdIsNormal(targitem));
1871 : Assert(ItemIdHasStorage(targitem));
1872 : htup = (HeapTupleHeader) PageGetItem(page, targitem);
1873 : Assert(HeapTupleHeaderIsHeapOnly(htup));
1874 : }
1875 : #endif
1876 121020 : }
1877 :
1878 :
1879 : /*
1880 : * For all items in this page, find their respective root line pointers.
1881 : * If item k is part of a HOT-chain with root at item j, then we set
1882 : * root_offsets[k - 1] = j.
1883 : *
1884 : * The passed-in root_offsets array must have MaxHeapTuplesPerPage entries.
1885 : * Unused entries are filled with InvalidOffsetNumber (zero).
1886 : *
1887 : * The function must be called with at least share lock on the buffer, to
1888 : * prevent concurrent prune operations.
1889 : *
1890 : * Note: The information collected here is valid only as long as the caller
1891 : * holds a pin on the buffer. Once pin is released, a tuple might be pruned
1892 : * and reused by a completely unrelated tuple.
1893 : */
1894 : void
1895 227630 : heap_get_root_tuples(Page page, OffsetNumber *root_offsets)
1896 : {
1897 : OffsetNumber offnum,
1898 : maxoff;
1899 :
1900 227630 : MemSet(root_offsets, InvalidOffsetNumber,
1901 : MaxHeapTuplesPerPage * sizeof(OffsetNumber));
1902 :
1903 227630 : maxoff = PageGetMaxOffsetNumber(page);
1904 18232608 : for (offnum = FirstOffsetNumber; offnum <= maxoff; offnum = OffsetNumberNext(offnum))
1905 : {
1906 18004978 : ItemId lp = PageGetItemId(page, offnum);
1907 : HeapTupleHeader htup;
1908 : OffsetNumber nextoffnum;
1909 : TransactionId priorXmax;
1910 :
1911 : /* skip unused and dead items */
1912 18004978 : if (!ItemIdIsUsed(lp) || ItemIdIsDead(lp))
1913 22240 : continue;
1914 :
1915 17982738 : if (ItemIdIsNormal(lp))
1916 : {
1917 17974294 : htup = (HeapTupleHeader) PageGetItem(page, lp);
1918 :
1919 : /*
1920 : * Check if this tuple is part of a HOT-chain rooted at some other
1921 : * tuple. If so, skip it for now; we'll process it when we find
1922 : * its root.
1923 : */
1924 17974294 : if (HeapTupleHeaderIsHeapOnly(htup))
1925 9068 : continue;
1926 :
1927 : /*
1928 : * This is either a plain tuple or the root of a HOT-chain.
1929 : * Remember it in the mapping.
1930 : */
1931 17965226 : root_offsets[offnum - 1] = offnum;
1932 :
1933 : /* If it's not the start of a HOT-chain, we're done with it */
1934 17965226 : if (!HeapTupleHeaderIsHotUpdated(htup))
1935 17964760 : continue;
1936 :
1937 : /* Set up to scan the HOT-chain */
1938 466 : nextoffnum = ItemPointerGetOffsetNumber(&htup->t_ctid);
1939 466 : priorXmax = HeapTupleHeaderGetUpdateXid(htup);
1940 : }
1941 : else
1942 : {
1943 : /* Must be a redirect item. We do not set its root_offsets entry */
1944 : Assert(ItemIdIsRedirected(lp));
1945 : /* Set up to scan the HOT-chain */
1946 8444 : nextoffnum = ItemIdGetRedirect(lp);
1947 8444 : priorXmax = InvalidTransactionId;
1948 : }
1949 :
1950 : /*
1951 : * Now follow the HOT-chain and collect other tuples in the chain.
1952 : *
1953 : * Note: Even though this is a nested loop, the complexity of the
1954 : * function is O(N) because a tuple in the page should be visited not
1955 : * more than twice, once in the outer loop and once in HOT-chain
1956 : * chases.
1957 : */
1958 : for (;;)
1959 : {
1960 : /* Sanity check (pure paranoia) */
1961 9062 : if (offnum < FirstOffsetNumber)
1962 0 : break;
1963 :
1964 : /*
1965 : * An offset past the end of page's line pointer array is possible
1966 : * when the array was truncated
1967 : */
1968 9062 : if (offnum > maxoff)
1969 0 : break;
1970 :
1971 9062 : lp = PageGetItemId(page, nextoffnum);
1972 :
1973 : /* Check for broken chains */
1974 9062 : if (!ItemIdIsNormal(lp))
1975 0 : break;
1976 :
1977 9062 : htup = (HeapTupleHeader) PageGetItem(page, lp);
1978 :
1979 9680 : if (TransactionIdIsValid(priorXmax) &&
1980 618 : !TransactionIdEquals(priorXmax, HeapTupleHeaderGetXmin(htup)))
1981 0 : break;
1982 :
1983 : /* Remember the root line pointer for this item */
1984 9062 : root_offsets[nextoffnum - 1] = offnum;
1985 :
1986 : /* Advance to next chain member, if any */
1987 9062 : if (!HeapTupleHeaderIsHotUpdated(htup))
1988 8910 : break;
1989 :
1990 : /* HOT implies it can't have moved to different partition */
1991 : Assert(!HeapTupleHeaderIndicatesMovedPartitions(htup));
1992 :
1993 152 : nextoffnum = ItemPointerGetOffsetNumber(&htup->t_ctid);
1994 152 : priorXmax = HeapTupleHeaderGetUpdateXid(htup);
1995 : }
1996 : }
1997 227630 : }
1998 :
1999 :
2000 : /*
2001 : * Compare fields that describe actions required to freeze tuple with caller's
2002 : * open plan. If everything matches then the frz tuple plan is equivalent to
2003 : * caller's plan.
2004 : */
2005 : static inline bool
2006 1882042 : heap_log_freeze_eq(xlhp_freeze_plan *plan, HeapTupleFreeze *frz)
2007 : {
2008 1882042 : if (plan->xmax == frz->xmax &&
2009 1879422 : plan->t_infomask2 == frz->t_infomask2 &&
2010 1877722 : plan->t_infomask == frz->t_infomask &&
2011 1872450 : plan->frzflags == frz->frzflags)
2012 1872450 : return true;
2013 :
2014 : /* Caller must call heap_log_freeze_new_plan again for frz */
2015 9592 : return false;
2016 : }
2017 :
2018 : /*
2019 : * Comparator used to deduplicate the freeze plans used in WAL records.
2020 : */
2021 : static int
2022 2621858 : heap_log_freeze_cmp(const void *arg1, const void *arg2)
2023 : {
2024 2621858 : HeapTupleFreeze *frz1 = (HeapTupleFreeze *) arg1;
2025 2621858 : HeapTupleFreeze *frz2 = (HeapTupleFreeze *) arg2;
2026 :
2027 2621858 : if (frz1->xmax < frz2->xmax)
2028 26544 : return -1;
2029 2595314 : else if (frz1->xmax > frz2->xmax)
2030 28194 : return 1;
2031 :
2032 2567120 : if (frz1->t_infomask2 < frz2->t_infomask2)
2033 9282 : return -1;
2034 2557838 : else if (frz1->t_infomask2 > frz2->t_infomask2)
2035 9406 : return 1;
2036 :
2037 2548432 : if (frz1->t_infomask < frz2->t_infomask)
2038 20790 : return -1;
2039 2527642 : else if (frz1->t_infomask > frz2->t_infomask)
2040 31540 : return 1;
2041 :
2042 2496102 : if (frz1->frzflags < frz2->frzflags)
2043 0 : return -1;
2044 2496102 : else if (frz1->frzflags > frz2->frzflags)
2045 0 : return 1;
2046 :
2047 : /*
2048 : * heap_log_freeze_eq would consider these tuple-wise plans to be equal.
2049 : * (So the tuples will share a single canonical freeze plan.)
2050 : *
2051 : * We tiebreak on page offset number to keep each freeze plan's page
2052 : * offset number array individually sorted. (Unnecessary, but be tidy.)
2053 : */
2054 2496102 : if (frz1->offset < frz2->offset)
2055 2102164 : return -1;
2056 393938 : else if (frz1->offset > frz2->offset)
2057 393938 : return 1;
2058 :
2059 : Assert(false);
2060 0 : return 0;
2061 : }
2062 :
2063 : /*
2064 : * Start new plan initialized using tuple-level actions. At least one tuple
2065 : * will have steps required to freeze described by caller's plan during REDO.
2066 : */
2067 : static inline void
2068 55698 : heap_log_freeze_new_plan(xlhp_freeze_plan *plan, HeapTupleFreeze *frz)
2069 : {
2070 55698 : plan->xmax = frz->xmax;
2071 55698 : plan->t_infomask2 = frz->t_infomask2;
2072 55698 : plan->t_infomask = frz->t_infomask;
2073 55698 : plan->frzflags = frz->frzflags;
2074 55698 : plan->ntuples = 1; /* for now */
2075 55698 : }
2076 :
2077 : /*
2078 : * Deduplicate tuple-based freeze plans so that each distinct set of
2079 : * processing steps is only stored once in the WAL record.
2080 : * Called during original execution of freezing (for logged relations).
2081 : *
2082 : * Return value is number of plans set in *plans_out for caller. Also writes
2083 : * an array of offset numbers into *offsets_out output argument for caller
2084 : * (actually there is one array per freeze plan, but that's not of immediate
2085 : * concern to our caller).
2086 : */
2087 : static int
2088 46106 : heap_log_freeze_plan(HeapTupleFreeze *tuples, int ntuples,
2089 : xlhp_freeze_plan *plans_out,
2090 : OffsetNumber *offsets_out)
2091 : {
2092 46106 : int nplans = 0;
2093 :
2094 : /* Sort tuple-based freeze plans in the order required to deduplicate */
2095 46106 : qsort(tuples, ntuples, sizeof(HeapTupleFreeze), heap_log_freeze_cmp);
2096 :
2097 1974254 : for (int i = 0; i < ntuples; i++)
2098 : {
2099 1928148 : HeapTupleFreeze *frz = tuples + i;
2100 :
2101 1928148 : if (i == 0)
2102 : {
2103 : /* New canonical freeze plan starting with first tup */
2104 46106 : heap_log_freeze_new_plan(plans_out, frz);
2105 46106 : nplans++;
2106 : }
2107 1882042 : else if (heap_log_freeze_eq(plans_out, frz))
2108 : {
2109 : /* tup matches open canonical plan -- include tup in it */
2110 : Assert(offsets_out[i - 1] < frz->offset);
2111 1872450 : plans_out->ntuples++;
2112 : }
2113 : else
2114 : {
2115 : /* Tup doesn't match current plan -- done with it now */
2116 9592 : plans_out++;
2117 :
2118 : /* New canonical freeze plan starting with this tup */
2119 9592 : heap_log_freeze_new_plan(plans_out, frz);
2120 9592 : nplans++;
2121 : }
2122 :
2123 : /*
2124 : * Save page offset number in dedicated buffer in passing.
2125 : *
2126 : * REDO routine relies on the record's offset numbers array grouping
2127 : * offset numbers by freeze plan. The sort order within each grouping
2128 : * is ascending offset number order, just to keep things tidy.
2129 : */
2130 1928148 : offsets_out[i] = frz->offset;
2131 : }
2132 :
2133 : Assert(nplans > 0 && nplans <= ntuples);
2134 :
2135 46106 : return nplans;
2136 : }
2137 :
2138 : /*
2139 : * Write an XLOG_HEAP2_PRUNE* WAL record
2140 : *
2141 : * This is used for several different page maintenance operations:
2142 : *
2143 : * - Page pruning, in VACUUM's 1st pass or on access: Some items are
2144 : * redirected, some marked dead, and some removed altogether.
2145 : *
2146 : * - Freezing: Items are marked as 'frozen'.
2147 : *
2148 : * - Vacuum, 2nd pass: Items that are already LP_DEAD are marked as unused.
2149 : *
2150 : * They have enough commonalities that we use a single WAL record for them
2151 : * all.
2152 : *
2153 : * If replaying the record requires a cleanup lock, pass cleanup_lock = true.
2154 : * Replaying 'redirected' or 'dead' items always requires a cleanup lock, but
2155 : * replaying 'unused' items depends on whether they were all previously marked
2156 : * as dead.
2157 : *
2158 : * If the VM is being updated, vmflags will contain the bits to set. In this
2159 : * case, vmbuffer should already have been updated and marked dirty and should
2160 : * still be pinned and locked.
2161 : *
2162 : * Note: This function scribbles on the 'frozen' array.
2163 : *
2164 : * Note: This is called in a critical section, so careful what you do here.
2165 : */
2166 : void
2167 172274 : log_heap_prune_and_freeze(Relation relation, Buffer buffer,
2168 : Buffer vmbuffer, uint8 vmflags,
2169 : TransactionId conflict_xid,
2170 : bool cleanup_lock,
2171 : PruneReason reason,
2172 : HeapTupleFreeze *frozen, int nfrozen,
2173 : OffsetNumber *redirected, int nredirected,
2174 : OffsetNumber *dead, int ndead,
2175 : OffsetNumber *unused, int nunused)
2176 : {
2177 : xl_heap_prune xlrec;
2178 : XLogRecPtr recptr;
2179 : uint8 info;
2180 : uint8 regbuf_flags_heap;
2181 :
2182 : /* The following local variables hold data registered in the WAL record: */
2183 : xlhp_freeze_plan plans[MaxHeapTuplesPerPage];
2184 : xlhp_freeze_plans freeze_plans;
2185 : xlhp_prune_items redirect_items;
2186 : xlhp_prune_items dead_items;
2187 : xlhp_prune_items unused_items;
2188 : OffsetNumber frz_offsets[MaxHeapTuplesPerPage];
2189 172274 : bool do_prune = nredirected > 0 || ndead > 0 || nunused > 0;
2190 172274 : bool do_set_vm = vmflags & VISIBILITYMAP_VALID_BITS;
2191 :
2192 : Assert((vmflags & VISIBILITYMAP_VALID_BITS) == vmflags);
2193 :
2194 172274 : xlrec.flags = 0;
2195 172274 : regbuf_flags_heap = REGBUF_STANDARD;
2196 :
2197 : /*
2198 : * We can avoid an FPI of the heap page if the only modification we are
2199 : * making to it is to set PD_ALL_VISIBLE and checksums/wal_log_hints are
2200 : * disabled. Note that if we explicitly skip an FPI, we must not stamp the
2201 : * heap page with this record's LSN. Recovery skips records <= the stamped
2202 : * LSN, so this could lead to skipping an earlier FPI needed to repair a
2203 : * torn page.
2204 : */
2205 172274 : if (!do_prune &&
2206 0 : nfrozen == 0 &&
2207 0 : (!do_set_vm || !XLogHintBitIsNeeded()))
2208 0 : regbuf_flags_heap |= REGBUF_NO_IMAGE;
2209 :
2210 : /*
2211 : * Prepare data for the buffer. The arrays are not actually in the
2212 : * buffer, but we pretend that they are. When XLogInsert stores a full
2213 : * page image, the arrays can be omitted.
2214 : */
2215 172274 : XLogBeginInsert();
2216 172274 : XLogRegisterBuffer(0, buffer, regbuf_flags_heap);
2217 :
2218 172274 : if (do_set_vm)
2219 24808 : XLogRegisterBuffer(1, vmbuffer, 0);
2220 :
2221 172274 : if (nfrozen > 0)
2222 : {
2223 : int nplans;
2224 :
2225 46106 : xlrec.flags |= XLHP_HAS_FREEZE_PLANS;
2226 :
2227 : /*
2228 : * Prepare deduplicated representation for use in the WAL record. This
2229 : * destructively sorts frozen tuples array in-place.
2230 : */
2231 46106 : nplans = heap_log_freeze_plan(frozen, nfrozen, plans, frz_offsets);
2232 :
2233 46106 : freeze_plans.nplans = nplans;
2234 46106 : XLogRegisterBufData(0, &freeze_plans,
2235 : offsetof(xlhp_freeze_plans, plans));
2236 46106 : XLogRegisterBufData(0, plans,
2237 : sizeof(xlhp_freeze_plan) * nplans);
2238 : }
2239 172274 : if (nredirected > 0)
2240 : {
2241 34438 : xlrec.flags |= XLHP_HAS_REDIRECTIONS;
2242 :
2243 34438 : redirect_items.ntargets = nredirected;
2244 34438 : XLogRegisterBufData(0, &redirect_items,
2245 : offsetof(xlhp_prune_items, data));
2246 34438 : XLogRegisterBufData(0, redirected,
2247 : sizeof(OffsetNumber[2]) * nredirected);
2248 : }
2249 172274 : if (ndead > 0)
2250 : {
2251 78052 : xlrec.flags |= XLHP_HAS_DEAD_ITEMS;
2252 :
2253 78052 : dead_items.ntargets = ndead;
2254 78052 : XLogRegisterBufData(0, &dead_items,
2255 : offsetof(xlhp_prune_items, data));
2256 78052 : XLogRegisterBufData(0, dead,
2257 : sizeof(OffsetNumber) * ndead);
2258 : }
2259 172274 : if (nunused > 0)
2260 : {
2261 48314 : xlrec.flags |= XLHP_HAS_NOW_UNUSED_ITEMS;
2262 :
2263 48314 : unused_items.ntargets = nunused;
2264 48314 : XLogRegisterBufData(0, &unused_items,
2265 : offsetof(xlhp_prune_items, data));
2266 48314 : XLogRegisterBufData(0, unused,
2267 : sizeof(OffsetNumber) * nunused);
2268 : }
2269 172274 : if (nfrozen > 0)
2270 46106 : XLogRegisterBufData(0, frz_offsets,
2271 : sizeof(OffsetNumber) * nfrozen);
2272 :
2273 : /*
2274 : * Prepare the main xl_heap_prune record. We already set the XLHP_HAS_*
2275 : * flag above.
2276 : */
2277 172274 : if (vmflags & VISIBILITYMAP_ALL_VISIBLE)
2278 : {
2279 24808 : xlrec.flags |= XLHP_VM_ALL_VISIBLE;
2280 24808 : if (vmflags & VISIBILITYMAP_ALL_FROZEN)
2281 19968 : xlrec.flags |= XLHP_VM_ALL_FROZEN;
2282 : }
2283 172274 : if (RelationIsAccessibleInLogicalDecoding(relation))
2284 1296 : xlrec.flags |= XLHP_IS_CATALOG_REL;
2285 172274 : if (TransactionIdIsValid(conflict_xid))
2286 142144 : xlrec.flags |= XLHP_HAS_CONFLICT_HORIZON;
2287 172274 : if (cleanup_lock)
2288 147208 : xlrec.flags |= XLHP_CLEANUP_LOCK;
2289 : else
2290 : {
2291 : Assert(nredirected == 0 && ndead == 0);
2292 : /* also, any items in 'unused' must've been LP_DEAD previously */
2293 : }
2294 172274 : XLogRegisterData(&xlrec, SizeOfHeapPrune);
2295 172274 : if (TransactionIdIsValid(conflict_xid))
2296 142144 : XLogRegisterData(&conflict_xid, sizeof(TransactionId));
2297 :
2298 172274 : switch (reason)
2299 : {
2300 84580 : case PRUNE_ON_ACCESS:
2301 84580 : info = XLOG_HEAP2_PRUNE_ON_ACCESS;
2302 84580 : break;
2303 62628 : case PRUNE_VACUUM_SCAN:
2304 62628 : info = XLOG_HEAP2_PRUNE_VACUUM_SCAN;
2305 62628 : break;
2306 25066 : case PRUNE_VACUUM_CLEANUP:
2307 25066 : info = XLOG_HEAP2_PRUNE_VACUUM_CLEANUP;
2308 25066 : break;
2309 0 : default:
2310 0 : elog(ERROR, "unrecognized prune reason: %d", (int) reason);
2311 : break;
2312 : }
2313 172274 : recptr = XLogInsert(RM_HEAP2_ID, info);
2314 :
2315 172274 : if (do_set_vm)
2316 : {
2317 : Assert(BufferIsDirty(vmbuffer));
2318 24808 : PageSetLSN(BufferGetPage(vmbuffer), recptr);
2319 : }
2320 :
2321 : /*
2322 : * See comment at the top of the function about regbuf_flags_heap for
2323 : * details on when we can advance the page LSN.
2324 : */
2325 172274 : if (do_prune || nfrozen > 0 || (do_set_vm && XLogHintBitIsNeeded()))
2326 : {
2327 : Assert(BufferIsDirty(buffer));
2328 172274 : PageSetLSN(BufferGetPage(buffer), recptr);
2329 : }
2330 172274 : }
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