Line data Source code
1 : /*-------------------------------------------------------------------------
2 : *
3 : * gist.c
4 : * interface routines for the postgres GiST index access method.
5 : *
6 : *
7 : * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
8 : * Portions Copyright (c) 1994, Regents of the University of California
9 : *
10 : * IDENTIFICATION
11 : * src/backend/access/gist/gist.c
12 : *
13 : *-------------------------------------------------------------------------
14 : */
15 : #include "postgres.h"
16 :
17 : #include "access/gist_private.h"
18 : #include "access/gistscan.h"
19 : #include "access/xloginsert.h"
20 : #include "catalog/pg_collation.h"
21 : #include "commands/vacuum.h"
22 : #include "miscadmin.h"
23 : #include "nodes/execnodes.h"
24 : #include "storage/predicate.h"
25 : #include "utils/fmgrprotos.h"
26 : #include "utils/index_selfuncs.h"
27 : #include "utils/memutils.h"
28 : #include "utils/rel.h"
29 :
30 : /* non-export function prototypes */
31 : static void gistfixsplit(GISTInsertState *state, GISTSTATE *giststate);
32 : static bool gistinserttuple(GISTInsertState *state, GISTInsertStack *stack,
33 : GISTSTATE *giststate, IndexTuple tuple, OffsetNumber oldoffnum);
34 : static bool gistinserttuples(GISTInsertState *state, GISTInsertStack *stack,
35 : GISTSTATE *giststate,
36 : IndexTuple *tuples, int ntup, OffsetNumber oldoffnum,
37 : Buffer leftchild, Buffer rightchild,
38 : bool unlockbuf, bool unlockleftchild);
39 : static void gistfinishsplit(GISTInsertState *state, GISTInsertStack *stack,
40 : GISTSTATE *giststate, List *splitinfo, bool unlockbuf);
41 : static void gistprunepage(Relation rel, Page page, Buffer buffer,
42 : Relation heapRel);
43 :
44 :
45 : #define ROTATEDIST(d) do { \
46 : SplitPageLayout *tmp = (SplitPageLayout *) palloc0(sizeof(SplitPageLayout)); \
47 : tmp->block.blkno = InvalidBlockNumber; \
48 : tmp->buffer = InvalidBuffer; \
49 : tmp->next = (d); \
50 : (d)=tmp; \
51 : } while(0)
52 :
53 :
54 : /*
55 : * GiST handler function: return IndexAmRoutine with access method parameters
56 : * and callbacks.
57 : */
58 : Datum
59 15372 : gisthandler(PG_FUNCTION_ARGS)
60 : {
61 15372 : IndexAmRoutine *amroutine = makeNode(IndexAmRoutine);
62 :
63 15372 : amroutine->amstrategies = 0;
64 15372 : amroutine->amsupport = GISTNProcs;
65 15372 : amroutine->amoptsprocnum = GIST_OPTIONS_PROC;
66 15372 : amroutine->amcanorder = false;
67 15372 : amroutine->amcanorderbyop = true;
68 15372 : amroutine->amcanhash = false;
69 15372 : amroutine->amconsistentequality = false;
70 15372 : amroutine->amconsistentordering = false;
71 15372 : amroutine->amcanbackward = false;
72 15372 : amroutine->amcanunique = false;
73 15372 : amroutine->amcanmulticol = true;
74 15372 : amroutine->amoptionalkey = true;
75 15372 : amroutine->amsearcharray = false;
76 15372 : amroutine->amsearchnulls = true;
77 15372 : amroutine->amstorage = true;
78 15372 : amroutine->amclusterable = true;
79 15372 : amroutine->ampredlocks = true;
80 15372 : amroutine->amcanparallel = false;
81 15372 : amroutine->amcanbuildparallel = false;
82 15372 : amroutine->amcaninclude = true;
83 15372 : amroutine->amusemaintenanceworkmem = false;
84 15372 : amroutine->amsummarizing = false;
85 15372 : amroutine->amparallelvacuumoptions =
86 : VACUUM_OPTION_PARALLEL_BULKDEL | VACUUM_OPTION_PARALLEL_COND_CLEANUP;
87 15372 : amroutine->amkeytype = InvalidOid;
88 :
89 15372 : amroutine->ambuild = gistbuild;
90 15372 : amroutine->ambuildempty = gistbuildempty;
91 15372 : amroutine->aminsert = gistinsert;
92 15372 : amroutine->aminsertcleanup = NULL;
93 15372 : amroutine->ambulkdelete = gistbulkdelete;
94 15372 : amroutine->amvacuumcleanup = gistvacuumcleanup;
95 15372 : amroutine->amcanreturn = gistcanreturn;
96 15372 : amroutine->amcostestimate = gistcostestimate;
97 15372 : amroutine->amgettreeheight = NULL;
98 15372 : amroutine->amoptions = gistoptions;
99 15372 : amroutine->amproperty = gistproperty;
100 15372 : amroutine->ambuildphasename = NULL;
101 15372 : amroutine->amvalidate = gistvalidate;
102 15372 : amroutine->amadjustmembers = gistadjustmembers;
103 15372 : amroutine->ambeginscan = gistbeginscan;
104 15372 : amroutine->amrescan = gistrescan;
105 15372 : amroutine->amgettuple = gistgettuple;
106 15372 : amroutine->amgetbitmap = gistgetbitmap;
107 15372 : amroutine->amendscan = gistendscan;
108 15372 : amroutine->ammarkpos = NULL;
109 15372 : amroutine->amrestrpos = NULL;
110 15372 : amroutine->amestimateparallelscan = NULL;
111 15372 : amroutine->aminitparallelscan = NULL;
112 15372 : amroutine->amparallelrescan = NULL;
113 15372 : amroutine->amtranslatestrategy = NULL;
114 15372 : amroutine->amtranslatecmptype = gisttranslatecmptype;
115 :
116 15372 : PG_RETURN_POINTER(amroutine);
117 : }
118 :
119 : /*
120 : * Create and return a temporary memory context for use by GiST. We
121 : * _always_ invoke user-provided methods in a temporary memory
122 : * context, so that memory leaks in those functions cannot cause
123 : * problems. Also, we use some additional temporary contexts in the
124 : * GiST code itself, to avoid the need to do some awkward manual
125 : * memory management.
126 : */
127 : MemoryContext
128 9782 : createTempGistContext(void)
129 : {
130 9782 : return AllocSetContextCreate(CurrentMemoryContext,
131 : "GiST temporary context",
132 : ALLOCSET_DEFAULT_SIZES);
133 : }
134 :
135 : /*
136 : * gistbuildempty() -- build an empty gist index in the initialization fork
137 : */
138 : void
139 10 : gistbuildempty(Relation index)
140 : {
141 : Buffer buffer;
142 :
143 : /* Initialize the root page */
144 10 : buffer = ExtendBufferedRel(BMR_REL(index), INIT_FORKNUM, NULL,
145 : EB_SKIP_EXTENSION_LOCK | EB_LOCK_FIRST);
146 :
147 : /* Initialize and xlog buffer */
148 10 : START_CRIT_SECTION();
149 10 : GISTInitBuffer(buffer, F_LEAF);
150 10 : MarkBufferDirty(buffer);
151 10 : log_newpage_buffer(buffer, true);
152 10 : END_CRIT_SECTION();
153 :
154 : /* Unlock and release the buffer */
155 10 : UnlockReleaseBuffer(buffer);
156 10 : }
157 :
158 : /*
159 : * gistinsert -- wrapper for GiST tuple insertion.
160 : *
161 : * This is the public interface routine for tuple insertion in GiSTs.
162 : * It doesn't do any work; just locks the relation and passes the buck.
163 : */
164 : bool
165 304310 : gistinsert(Relation r, Datum *values, bool *isnull,
166 : ItemPointer ht_ctid, Relation heapRel,
167 : IndexUniqueCheck checkUnique,
168 : bool indexUnchanged,
169 : IndexInfo *indexInfo)
170 : {
171 304310 : GISTSTATE *giststate = (GISTSTATE *) indexInfo->ii_AmCache;
172 : IndexTuple itup;
173 : MemoryContext oldCxt;
174 :
175 : /* Initialize GISTSTATE cache if first call in this statement */
176 304310 : if (giststate == NULL)
177 : {
178 1920 : oldCxt = MemoryContextSwitchTo(indexInfo->ii_Context);
179 1920 : giststate = initGISTstate(r);
180 1920 : giststate->tempCxt = createTempGistContext();
181 1920 : indexInfo->ii_AmCache = giststate;
182 1920 : MemoryContextSwitchTo(oldCxt);
183 : }
184 :
185 304310 : oldCxt = MemoryContextSwitchTo(giststate->tempCxt);
186 :
187 304310 : itup = gistFormTuple(giststate, r, values, isnull, true);
188 304308 : itup->t_tid = *ht_ctid;
189 :
190 304308 : gistdoinsert(r, itup, 0, giststate, heapRel, false);
191 :
192 : /* cleanup */
193 304296 : MemoryContextSwitchTo(oldCxt);
194 304296 : MemoryContextReset(giststate->tempCxt);
195 :
196 304296 : return false;
197 : }
198 :
199 :
200 : /*
201 : * Place tuples from 'itup' to 'buffer'. If 'oldoffnum' is valid, the tuple
202 : * at that offset is atomically removed along with inserting the new tuples.
203 : * This is used to replace a tuple with a new one.
204 : *
205 : * If 'leftchildbuf' is valid, we're inserting the downlink for the page
206 : * to the right of 'leftchildbuf', or updating the downlink for 'leftchildbuf'.
207 : * F_FOLLOW_RIGHT flag on 'leftchildbuf' is cleared and NSN is set.
208 : *
209 : * If 'markfollowright' is true and the page is split, the left child is
210 : * marked with F_FOLLOW_RIGHT flag. That is the normal case. During buffered
211 : * index build, however, there is no concurrent access and the page splitting
212 : * is done in a slightly simpler fashion, and false is passed.
213 : *
214 : * If there is not enough room on the page, it is split. All the split
215 : * pages are kept pinned and locked and returned in *splitinfo, the caller
216 : * is responsible for inserting the downlinks for them. However, if
217 : * 'buffer' is the root page and it needs to be split, gistplacetopage()
218 : * performs the split as one atomic operation, and *splitinfo is set to NIL.
219 : * In that case, we continue to hold the root page locked, and the child
220 : * pages are released; note that new tuple(s) are *not* on the root page
221 : * but in one of the new child pages.
222 : *
223 : * If 'newblkno' is not NULL, returns the block number of page the first
224 : * new/updated tuple was inserted to. Usually it's the given page, but could
225 : * be its right sibling if the page was split.
226 : *
227 : * Returns 'true' if the page was split, 'false' otherwise.
228 : */
229 : bool
230 1631480 : gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
231 : Buffer buffer,
232 : IndexTuple *itup, int ntup, OffsetNumber oldoffnum,
233 : BlockNumber *newblkno,
234 : Buffer leftchildbuf,
235 : List **splitinfo,
236 : bool markfollowright,
237 : Relation heapRel,
238 : bool is_build)
239 : {
240 1631480 : BlockNumber blkno = BufferGetBlockNumber(buffer);
241 1631480 : Page page = BufferGetPage(buffer);
242 1631480 : bool is_leaf = (GistPageIsLeaf(page)) ? true : false;
243 : XLogRecPtr recptr;
244 : bool is_split;
245 :
246 : /*
247 : * Refuse to modify a page that's incompletely split. This should not
248 : * happen because we finish any incomplete splits while we walk down the
249 : * tree. However, it's remotely possible that another concurrent inserter
250 : * splits a parent page, and errors out before completing the split. We
251 : * will just throw an error in that case, and leave any split we had in
252 : * progress unfinished too. The next insert that comes along will clean up
253 : * the mess.
254 : */
255 1631480 : if (GistFollowRight(page))
256 0 : elog(ERROR, "concurrent GiST page split was incomplete");
257 :
258 : /* should never try to insert to a deleted page */
259 : Assert(!GistPageIsDeleted(page));
260 :
261 1631480 : *splitinfo = NIL;
262 :
263 : /*
264 : * if isupdate, remove old key: This node's key has been modified, either
265 : * because a child split occurred or because we needed to adjust our key
266 : * for an insert in a child node. Therefore, remove the old version of
267 : * this node's key.
268 : *
269 : * for WAL replay, in the non-split case we handle this by setting up a
270 : * one-element todelete array; in the split case, it's handled implicitly
271 : * because the tuple vector passed to gistSplit won't include this tuple.
272 : */
273 1631480 : is_split = gistnospace(page, itup, ntup, oldoffnum, freespace);
274 :
275 : /*
276 : * If leaf page is full, try at first to delete dead tuples. And then
277 : * check again.
278 : */
279 1631480 : if (is_split && GistPageIsLeaf(page) && GistPageHasGarbage(page))
280 : {
281 0 : gistprunepage(rel, page, buffer, heapRel);
282 0 : is_split = gistnospace(page, itup, ntup, oldoffnum, freespace);
283 : }
284 :
285 1631480 : if (is_split)
286 : {
287 : /* no space for insertion */
288 : IndexTuple *itvec;
289 : int tlen;
290 25184 : SplitPageLayout *dist = NULL,
291 : *ptr;
292 25184 : BlockNumber oldrlink = InvalidBlockNumber;
293 25184 : GistNSN oldnsn = 0;
294 : SplitPageLayout rootpg;
295 : bool is_rootsplit;
296 : int npage;
297 :
298 25184 : is_rootsplit = (blkno == GIST_ROOT_BLKNO);
299 :
300 : /*
301 : * Form index tuples vector to split. If we're replacing an old tuple,
302 : * remove the old version from the vector.
303 : */
304 25184 : itvec = gistextractpage(page, &tlen);
305 25184 : if (OffsetNumberIsValid(oldoffnum))
306 : {
307 : /* on inner page we should remove old tuple */
308 5534 : int pos = oldoffnum - FirstOffsetNumber;
309 :
310 5534 : tlen--;
311 5534 : if (pos != tlen)
312 3528 : memmove(itvec + pos, itvec + pos + 1, sizeof(IndexTuple) * (tlen - pos));
313 : }
314 25184 : itvec = gistjoinvector(itvec, &tlen, itup, ntup);
315 25184 : dist = gistSplit(rel, page, itvec, tlen, giststate);
316 :
317 : /*
318 : * Check that split didn't produce too many pages.
319 : */
320 25184 : npage = 0;
321 75668 : for (ptr = dist; ptr; ptr = ptr->next)
322 50484 : npage++;
323 : /* in a root split, we'll add one more page to the list below */
324 25184 : if (is_rootsplit)
325 356 : npage++;
326 25184 : if (npage > GIST_MAX_SPLIT_PAGES)
327 0 : elog(ERROR, "GiST page split into too many halves (%d, maximum %d)",
328 : npage, GIST_MAX_SPLIT_PAGES);
329 :
330 : /*
331 : * Set up pages to work with. Allocate new buffers for all but the
332 : * leftmost page. The original page becomes the new leftmost page, and
333 : * is just replaced with the new contents.
334 : *
335 : * For a root-split, allocate new buffers for all child pages, the
336 : * original page is overwritten with new root page containing
337 : * downlinks to the new child pages.
338 : */
339 25184 : ptr = dist;
340 25184 : if (!is_rootsplit)
341 : {
342 : /* save old rightlink and NSN */
343 24828 : oldrlink = GistPageGetOpaque(page)->rightlink;
344 24828 : oldnsn = GistPageGetNSN(page);
345 :
346 24828 : dist->buffer = buffer;
347 24828 : dist->block.blkno = BufferGetBlockNumber(buffer);
348 24828 : dist->page = PageGetTempPageCopySpecial(BufferGetPage(buffer));
349 :
350 : /* clean all flags except F_LEAF */
351 24828 : GistPageGetOpaque(dist->page)->flags = (is_leaf) ? F_LEAF : 0;
352 :
353 24828 : ptr = ptr->next;
354 : }
355 50840 : for (; ptr; ptr = ptr->next)
356 : {
357 : /* Allocate new page */
358 25656 : ptr->buffer = gistNewBuffer(rel, heapRel);
359 25656 : GISTInitBuffer(ptr->buffer, (is_leaf) ? F_LEAF : 0);
360 25656 : ptr->page = BufferGetPage(ptr->buffer);
361 25656 : ptr->block.blkno = BufferGetBlockNumber(ptr->buffer);
362 25656 : PredicateLockPageSplit(rel,
363 : BufferGetBlockNumber(buffer),
364 : BufferGetBlockNumber(ptr->buffer));
365 : }
366 :
367 : /*
368 : * Now that we know which blocks the new pages go to, set up downlink
369 : * tuples to point to them.
370 : */
371 75668 : for (ptr = dist; ptr; ptr = ptr->next)
372 : {
373 50484 : ItemPointerSetBlockNumber(&(ptr->itup->t_tid), ptr->block.blkno);
374 50484 : GistTupleSetValid(ptr->itup);
375 : }
376 :
377 : /*
378 : * If this is a root split, we construct the new root page with the
379 : * downlinks here directly, instead of requiring the caller to insert
380 : * them. Add the new root page to the list along with the child pages.
381 : */
382 25184 : if (is_rootsplit)
383 : {
384 : IndexTuple *downlinks;
385 356 : int ndownlinks = 0;
386 : int i;
387 :
388 356 : rootpg.buffer = buffer;
389 356 : rootpg.page = PageGetTempPageCopySpecial(BufferGetPage(rootpg.buffer));
390 356 : GistPageGetOpaque(rootpg.page)->flags = 0;
391 :
392 : /* Prepare a vector of all the downlinks */
393 1074 : for (ptr = dist; ptr; ptr = ptr->next)
394 718 : ndownlinks++;
395 356 : downlinks = palloc(sizeof(IndexTuple) * ndownlinks);
396 1074 : for (i = 0, ptr = dist; ptr; ptr = ptr->next)
397 718 : downlinks[i++] = ptr->itup;
398 :
399 356 : rootpg.block.blkno = GIST_ROOT_BLKNO;
400 356 : rootpg.block.num = ndownlinks;
401 356 : rootpg.list = gistfillitupvec(downlinks, ndownlinks,
402 : &(rootpg.lenlist));
403 356 : rootpg.itup = NULL;
404 :
405 356 : rootpg.next = dist;
406 356 : dist = &rootpg;
407 : }
408 : else
409 : {
410 : /* Prepare split-info to be returned to caller */
411 74594 : for (ptr = dist; ptr; ptr = ptr->next)
412 : {
413 49766 : GISTPageSplitInfo *si = palloc(sizeof(GISTPageSplitInfo));
414 :
415 49766 : si->buf = ptr->buffer;
416 49766 : si->downlink = ptr->itup;
417 49766 : *splitinfo = lappend(*splitinfo, si);
418 : }
419 : }
420 :
421 : /*
422 : * Fill all pages. All the pages are new, ie. freshly allocated empty
423 : * pages, or a temporary copy of the old page.
424 : */
425 76024 : for (ptr = dist; ptr; ptr = ptr->next)
426 : {
427 50840 : char *data = (char *) (ptr->list);
428 :
429 1772254 : for (int i = 0; i < ptr->block.num; i++)
430 : {
431 1721414 : IndexTuple thistup = (IndexTuple) data;
432 :
433 1721414 : if (PageAddItem(ptr->page, data, IndexTupleSize(thistup), i + FirstOffsetNumber, false, false) == InvalidOffsetNumber)
434 0 : elog(ERROR, "failed to add item to index page in \"%s\"", RelationGetRelationName(rel));
435 :
436 : /*
437 : * If this is the first inserted/updated tuple, let the caller
438 : * know which page it landed on.
439 : */
440 1721414 : if (newblkno && ItemPointerEquals(&thistup->t_tid, &(*itup)->t_tid))
441 774 : *newblkno = ptr->block.blkno;
442 :
443 1721414 : data += IndexTupleSize(thistup);
444 : }
445 :
446 : /* Set up rightlinks */
447 50840 : if (ptr->next && ptr->block.blkno != GIST_ROOT_BLKNO)
448 50600 : GistPageGetOpaque(ptr->page)->rightlink =
449 25300 : ptr->next->block.blkno;
450 : else
451 25540 : GistPageGetOpaque(ptr->page)->rightlink = oldrlink;
452 :
453 : /*
454 : * Mark the all but the right-most page with the follow-right
455 : * flag. It will be cleared as soon as the downlink is inserted
456 : * into the parent, but this ensures that if we error out before
457 : * that, the index is still consistent. (in buffering build mode,
458 : * any error will abort the index build anyway, so this is not
459 : * needed.)
460 : */
461 50840 : if (ptr->next && !is_rootsplit && markfollowright)
462 24170 : GistMarkFollowRight(ptr->page);
463 : else
464 26670 : GistClearFollowRight(ptr->page);
465 :
466 : /*
467 : * Copy the NSN of the original page to all pages. The
468 : * F_FOLLOW_RIGHT flags ensure that scans will follow the
469 : * rightlinks until the downlinks are inserted.
470 : */
471 50840 : GistPageSetNSN(ptr->page, oldnsn);
472 : }
473 :
474 : /*
475 : * gistXLogSplit() needs to WAL log a lot of pages, prepare WAL
476 : * insertion for that. NB: The number of pages and data segments
477 : * specified here must match the calculations in gistXLogSplit()!
478 : */
479 25184 : if (!is_build && RelationNeedsWAL(rel))
480 3462 : XLogEnsureRecordSpace(npage, 1 + npage * 2);
481 :
482 25184 : START_CRIT_SECTION();
483 :
484 : /*
485 : * Must mark buffers dirty before XLogInsert, even though we'll still
486 : * be changing their opaque fields below.
487 : */
488 76024 : for (ptr = dist; ptr; ptr = ptr->next)
489 50840 : MarkBufferDirty(ptr->buffer);
490 25184 : if (BufferIsValid(leftchildbuf))
491 5354 : MarkBufferDirty(leftchildbuf);
492 :
493 : /*
494 : * The first page in the chain was a temporary working copy meant to
495 : * replace the old page. Copy it over the old page.
496 : */
497 25184 : PageRestoreTempPage(dist->page, BufferGetPage(dist->buffer));
498 25184 : dist->page = BufferGetPage(dist->buffer);
499 :
500 : /*
501 : * Write the WAL record.
502 : *
503 : * If we're building a new index, however, we don't WAL-log changes
504 : * yet. The LSN-NSN interlock between parent and child requires that
505 : * LSNs never move backwards, so set the LSNs to a value that's
506 : * smaller than any real or fake unlogged LSN that might be generated
507 : * later. (There can't be any concurrent scans during index build, so
508 : * we don't need to be able to detect concurrent splits yet.)
509 : */
510 25184 : if (is_build)
511 21718 : recptr = GistBuildLSN;
512 : else
513 : {
514 3466 : if (RelationNeedsWAL(rel))
515 3462 : recptr = gistXLogSplit(is_leaf,
516 : dist, oldrlink, oldnsn, leftchildbuf,
517 : markfollowright);
518 : else
519 4 : recptr = gistGetFakeLSN(rel);
520 : }
521 :
522 76024 : for (ptr = dist; ptr; ptr = ptr->next)
523 50840 : PageSetLSN(ptr->page, recptr);
524 :
525 : /*
526 : * Return the new child buffers to the caller.
527 : *
528 : * If this was a root split, we've already inserted the downlink
529 : * pointers, in the form of a new root page. Therefore we can release
530 : * all the new buffers, and keep just the root page locked.
531 : */
532 25184 : if (is_rootsplit)
533 : {
534 1074 : for (ptr = dist->next; ptr; ptr = ptr->next)
535 718 : UnlockReleaseBuffer(ptr->buffer);
536 : }
537 : }
538 : else
539 : {
540 : /*
541 : * Enough space. We always get here if ntup==0.
542 : */
543 1606296 : START_CRIT_SECTION();
544 :
545 : /*
546 : * Delete old tuple if any, then insert new tuple(s) if any. If
547 : * possible, use the fast path of PageIndexTupleOverwrite.
548 : */
549 1606296 : if (OffsetNumberIsValid(oldoffnum))
550 : {
551 735792 : if (ntup == 1)
552 : {
553 : /* One-for-one replacement, so use PageIndexTupleOverwrite */
554 716324 : if (!PageIndexTupleOverwrite(page, oldoffnum, *itup, IndexTupleSize(*itup)))
555 0 : elog(ERROR, "failed to add item to index page in \"%s\"",
556 : RelationGetRelationName(rel));
557 : }
558 : else
559 : {
560 : /* Delete old, then append new tuple(s) to page */
561 19468 : PageIndexTupleDelete(page, oldoffnum);
562 19468 : gistfillbuffer(page, itup, ntup, InvalidOffsetNumber);
563 : }
564 : }
565 : else
566 : {
567 : /* Just append new tuples at the end of the page */
568 870504 : gistfillbuffer(page, itup, ntup, InvalidOffsetNumber);
569 : }
570 :
571 1606296 : MarkBufferDirty(buffer);
572 :
573 1606296 : if (BufferIsValid(leftchildbuf))
574 18816 : MarkBufferDirty(leftchildbuf);
575 :
576 1606296 : if (is_build)
577 1111704 : recptr = GistBuildLSN;
578 : else
579 : {
580 494592 : if (RelationNeedsWAL(rel))
581 494514 : {
582 494514 : OffsetNumber ndeloffs = 0,
583 : deloffs[1];
584 :
585 494514 : if (OffsetNumberIsValid(oldoffnum))
586 : {
587 193740 : deloffs[0] = oldoffnum;
588 193740 : ndeloffs = 1;
589 : }
590 :
591 494514 : recptr = gistXLogUpdate(buffer,
592 : deloffs, ndeloffs, itup, ntup,
593 : leftchildbuf);
594 : }
595 : else
596 78 : recptr = gistGetFakeLSN(rel);
597 : }
598 1606296 : PageSetLSN(page, recptr);
599 :
600 1606296 : if (newblkno)
601 104370 : *newblkno = blkno;
602 : }
603 :
604 : /*
605 : * If we inserted the downlink for a child page, set NSN and clear
606 : * F_FOLLOW_RIGHT flag on the left child, so that concurrent scans know to
607 : * follow the rightlink if and only if they looked at the parent page
608 : * before we inserted the downlink.
609 : *
610 : * Note that we do this *after* writing the WAL record. That means that
611 : * the possible full page image in the WAL record does not include these
612 : * changes, and they must be replayed even if the page is restored from
613 : * the full page image. There's a chicken-and-egg problem: if we updated
614 : * the child pages first, we wouldn't know the recptr of the WAL record
615 : * we're about to write.
616 : */
617 1631480 : if (BufferIsValid(leftchildbuf))
618 : {
619 24170 : Page leftpg = BufferGetPage(leftchildbuf);
620 :
621 24170 : GistPageSetNSN(leftpg, recptr);
622 24170 : GistClearFollowRight(leftpg);
623 :
624 24170 : PageSetLSN(leftpg, recptr);
625 : }
626 :
627 1631480 : END_CRIT_SECTION();
628 :
629 1631480 : return is_split;
630 : }
631 :
632 : /*
633 : * Workhorse routine for doing insertion into a GiST index. Note that
634 : * this routine assumes it is invoked in a short-lived memory context,
635 : * so it does not bother releasing palloc'd allocations.
636 : */
637 : void
638 854626 : gistdoinsert(Relation r, IndexTuple itup, Size freespace,
639 : GISTSTATE *giststate, Relation heapRel, bool is_build)
640 : {
641 : ItemId iid;
642 : IndexTuple idxtuple;
643 : GISTInsertStack firststack;
644 : GISTInsertStack *stack;
645 : GISTInsertState state;
646 854626 : bool xlocked = false;
647 :
648 854626 : memset(&state, 0, sizeof(GISTInsertState));
649 854626 : state.freespace = freespace;
650 854626 : state.r = r;
651 854626 : state.heapRel = heapRel;
652 854626 : state.is_build = is_build;
653 :
654 : /* Start from the root */
655 854626 : firststack.blkno = GIST_ROOT_BLKNO;
656 854626 : firststack.lsn = 0;
657 854626 : firststack.retry_from_parent = false;
658 854626 : firststack.parent = NULL;
659 854626 : firststack.downlinkoffnum = InvalidOffsetNumber;
660 854626 : state.stack = stack = &firststack;
661 :
662 : /*
663 : * Walk down along the path of smallest penalty, updating the parent
664 : * pointers with the key we're inserting as we go. If we crash in the
665 : * middle, the tree is consistent, although the possible parent updates
666 : * were a waste.
667 : */
668 : for (;;)
669 : {
670 : /*
671 : * If we split an internal page while descending the tree, we have to
672 : * retry at the parent. (Normally, the LSN-NSN interlock below would
673 : * also catch this and cause us to retry. But LSNs are not updated
674 : * during index build.)
675 : */
676 1978630 : while (stack->retry_from_parent)
677 : {
678 382 : if (xlocked)
679 0 : LockBuffer(stack->buffer, GIST_UNLOCK);
680 382 : xlocked = false;
681 382 : ReleaseBuffer(stack->buffer);
682 382 : state.stack = stack = stack->parent;
683 : }
684 :
685 1978248 : if (XLogRecPtrIsInvalid(stack->lsn))
686 1978074 : stack->buffer = ReadBuffer(state.r, stack->blkno);
687 :
688 : /*
689 : * Be optimistic and grab shared lock first. Swap it for an exclusive
690 : * lock later if we need to update the page.
691 : */
692 1978248 : if (!xlocked)
693 : {
694 1978246 : LockBuffer(stack->buffer, GIST_SHARE);
695 1978246 : gistcheckpage(state.r, stack->buffer);
696 : }
697 :
698 1978248 : stack->page = BufferGetPage(stack->buffer);
699 1978248 : stack->lsn = xlocked ?
700 1978248 : PageGetLSN(stack->page) : BufferGetLSNAtomic(stack->buffer);
701 : Assert(!RelationNeedsWAL(state.r) || !XLogRecPtrIsInvalid(stack->lsn));
702 :
703 : /*
704 : * If this page was split but the downlink was never inserted to the
705 : * parent because the inserting backend crashed before doing that, fix
706 : * that now.
707 : */
708 1978248 : if (GistFollowRight(stack->page))
709 : {
710 0 : if (!xlocked)
711 : {
712 0 : LockBuffer(stack->buffer, GIST_UNLOCK);
713 0 : LockBuffer(stack->buffer, GIST_EXCLUSIVE);
714 0 : xlocked = true;
715 : /* someone might've completed the split when we unlocked */
716 0 : if (!GistFollowRight(stack->page))
717 0 : continue;
718 : }
719 0 : gistfixsplit(&state, giststate);
720 :
721 0 : UnlockReleaseBuffer(stack->buffer);
722 0 : xlocked = false;
723 0 : state.stack = stack = stack->parent;
724 0 : continue;
725 : }
726 :
727 3101738 : if ((stack->blkno != GIST_ROOT_BLKNO &&
728 1123490 : stack->parent->lsn < GistPageGetNSN(stack->page)) ||
729 1978248 : GistPageIsDeleted(stack->page))
730 : {
731 : /*
732 : * Concurrent split or page deletion detected. There's no
733 : * guarantee that the downlink for this page is consistent with
734 : * the tuple we're inserting anymore, so go back to parent and
735 : * rechoose the best child.
736 : */
737 0 : UnlockReleaseBuffer(stack->buffer);
738 0 : xlocked = false;
739 0 : state.stack = stack = stack->parent;
740 0 : continue;
741 : }
742 :
743 1978248 : if (!GistPageIsLeaf(stack->page))
744 : {
745 : /*
746 : * This is an internal page so continue to walk down the tree.
747 : * Find the child node that has the minimum insertion penalty.
748 : */
749 : BlockNumber childblkno;
750 : IndexTuple newtup;
751 : GISTInsertStack *item;
752 : OffsetNumber downlinkoffnum;
753 :
754 1123622 : downlinkoffnum = gistchoose(state.r, stack->page, itup, giststate);
755 1123622 : iid = PageGetItemId(stack->page, downlinkoffnum);
756 1123622 : idxtuple = (IndexTuple) PageGetItem(stack->page, iid);
757 1123622 : childblkno = ItemPointerGetBlockNumber(&(idxtuple->t_tid));
758 :
759 : /*
760 : * Check that it's not a leftover invalid tuple from pre-9.1
761 : */
762 1123622 : if (GistTupleIsInvalid(idxtuple))
763 0 : ereport(ERROR,
764 : (errmsg("index \"%s\" contains an inner tuple marked as invalid",
765 : RelationGetRelationName(r)),
766 : errdetail("This is caused by an incomplete page split at crash recovery before upgrading to PostgreSQL 9.1."),
767 : errhint("Please REINDEX it.")));
768 :
769 : /*
770 : * Check that the key representing the target child node is
771 : * consistent with the key we're inserting. Update it if it's not.
772 : */
773 1123622 : newtup = gistgetadjusted(state.r, idxtuple, itup, giststate);
774 1123622 : if (newtup)
775 : {
776 : /*
777 : * Swap shared lock for an exclusive one. Beware, the page may
778 : * change while we unlock/lock the page...
779 : */
780 647552 : if (!xlocked)
781 : {
782 647552 : LockBuffer(stack->buffer, GIST_UNLOCK);
783 647552 : LockBuffer(stack->buffer, GIST_EXCLUSIVE);
784 647552 : xlocked = true;
785 647552 : stack->page = BufferGetPage(stack->buffer);
786 :
787 647552 : if (PageGetLSN(stack->page) != stack->lsn)
788 : {
789 : /* the page was changed while we unlocked it, retry */
790 0 : continue;
791 : }
792 : }
793 :
794 : /*
795 : * Update the tuple.
796 : *
797 : * We still hold the lock after gistinserttuple(), but it
798 : * might have to split the page to make the updated tuple fit.
799 : * In that case the updated tuple might migrate to the other
800 : * half of the split, so we have to go back to the parent and
801 : * descend back to the half that's a better fit for the new
802 : * tuple.
803 : */
804 647552 : if (gistinserttuple(&state, stack, giststate, newtup,
805 : downlinkoffnum))
806 : {
807 : /*
808 : * If this was a root split, the root page continues to be
809 : * the parent and the updated tuple went to one of the
810 : * child pages, so we just need to retry from the root
811 : * page.
812 : */
813 174 : if (stack->blkno != GIST_ROOT_BLKNO)
814 : {
815 172 : UnlockReleaseBuffer(stack->buffer);
816 172 : xlocked = false;
817 172 : state.stack = stack = stack->parent;
818 : }
819 174 : continue;
820 : }
821 : }
822 1123448 : LockBuffer(stack->buffer, GIST_UNLOCK);
823 1123448 : xlocked = false;
824 :
825 : /* descend to the chosen child */
826 1123448 : item = (GISTInsertStack *) palloc0(sizeof(GISTInsertStack));
827 1123448 : item->blkno = childblkno;
828 1123448 : item->parent = stack;
829 1123448 : item->downlinkoffnum = downlinkoffnum;
830 1123448 : state.stack = stack = item;
831 : }
832 : else
833 : {
834 : /*
835 : * Leaf page. Insert the new key. We've already updated all the
836 : * parents on the way down, but we might have to split the page if
837 : * it doesn't fit. gistinserttuple() will take care of that.
838 : */
839 :
840 : /*
841 : * Swap shared lock for an exclusive one. Be careful, the page may
842 : * change while we unlock/lock the page...
843 : */
844 854626 : if (!xlocked)
845 : {
846 854626 : LockBuffer(stack->buffer, GIST_UNLOCK);
847 854626 : LockBuffer(stack->buffer, GIST_EXCLUSIVE);
848 854626 : xlocked = true;
849 854626 : stack->page = BufferGetPage(stack->buffer);
850 854626 : stack->lsn = PageGetLSN(stack->page);
851 :
852 854626 : if (stack->blkno == GIST_ROOT_BLKNO)
853 : {
854 : /*
855 : * the only page that can become inner instead of leaf is
856 : * the root page, so for root we should recheck it
857 : */
858 38802 : if (!GistPageIsLeaf(stack->page))
859 : {
860 : /*
861 : * very rare situation: during unlock/lock index with
862 : * number of pages = 1 was increased
863 : */
864 0 : LockBuffer(stack->buffer, GIST_UNLOCK);
865 0 : xlocked = false;
866 0 : continue;
867 : }
868 :
869 : /*
870 : * we don't need to check root split, because checking
871 : * leaf/inner is enough to recognize split for root
872 : */
873 : }
874 1631648 : else if ((GistFollowRight(stack->page) ||
875 815824 : stack->parent->lsn < GistPageGetNSN(stack->page)) ||
876 815824 : GistPageIsDeleted(stack->page))
877 : {
878 : /*
879 : * The page was split or deleted while we momentarily
880 : * unlocked the page. Go back to parent.
881 : */
882 0 : UnlockReleaseBuffer(stack->buffer);
883 0 : xlocked = false;
884 0 : state.stack = stack = stack->parent;
885 0 : continue;
886 : }
887 : }
888 :
889 : /* now state.stack->(page, buffer and blkno) points to leaf page */
890 :
891 854626 : gistinserttuple(&state, stack, giststate, itup,
892 : InvalidOffsetNumber);
893 854614 : LockBuffer(stack->buffer, GIST_UNLOCK);
894 :
895 : /* Release any pins we might still hold before exiting */
896 2832112 : for (; stack; stack = stack->parent)
897 1977498 : ReleaseBuffer(stack->buffer);
898 854614 : break;
899 : }
900 : }
901 854614 : }
902 :
903 : /*
904 : * Traverse the tree to find path from root page to specified "child" block.
905 : *
906 : * returns a new insertion stack, starting from the parent of "child", up
907 : * to the root. *downlinkoffnum is set to the offset of the downlink in the
908 : * direct parent of child.
909 : *
910 : * To prevent deadlocks, this should lock only one page at a time.
911 : */
912 : static GISTInsertStack *
913 2 : gistFindPath(Relation r, BlockNumber child, OffsetNumber *downlinkoffnum)
914 : {
915 : Page page;
916 : Buffer buffer;
917 : OffsetNumber i,
918 : maxoff;
919 : ItemId iid;
920 : IndexTuple idxtuple;
921 : List *fifo;
922 : GISTInsertStack *top,
923 : *ptr;
924 : BlockNumber blkno;
925 :
926 2 : top = (GISTInsertStack *) palloc0(sizeof(GISTInsertStack));
927 2 : top->blkno = GIST_ROOT_BLKNO;
928 2 : top->downlinkoffnum = InvalidOffsetNumber;
929 :
930 2 : fifo = list_make1(top);
931 4 : while (fifo != NIL)
932 : {
933 : /* Get next page to visit */
934 4 : top = linitial(fifo);
935 4 : fifo = list_delete_first(fifo);
936 :
937 4 : buffer = ReadBuffer(r, top->blkno);
938 4 : LockBuffer(buffer, GIST_SHARE);
939 4 : gistcheckpage(r, buffer);
940 4 : page = BufferGetPage(buffer);
941 :
942 4 : if (GistPageIsLeaf(page))
943 : {
944 : /*
945 : * Because we scan the index top-down, all the rest of the pages
946 : * in the queue must be leaf pages as well.
947 : */
948 0 : UnlockReleaseBuffer(buffer);
949 0 : break;
950 : }
951 :
952 : /* currently, internal pages are never deleted */
953 : Assert(!GistPageIsDeleted(page));
954 :
955 4 : top->lsn = BufferGetLSNAtomic(buffer);
956 :
957 : /*
958 : * If F_FOLLOW_RIGHT is set, the page to the right doesn't have a
959 : * downlink. This should not normally happen..
960 : */
961 4 : if (GistFollowRight(page))
962 0 : elog(ERROR, "concurrent GiST page split was incomplete");
963 :
964 4 : if (top->parent && top->parent->lsn < GistPageGetNSN(page) &&
965 0 : GistPageGetOpaque(page)->rightlink != InvalidBlockNumber /* sanity check */ )
966 : {
967 : /*
968 : * Page was split while we looked elsewhere. We didn't see the
969 : * downlink to the right page when we scanned the parent, so add
970 : * it to the queue now.
971 : *
972 : * Put the right page ahead of the queue, so that we visit it
973 : * next. That's important, because if this is the lowest internal
974 : * level, just above leaves, we might already have queued up some
975 : * leaf pages, and we assume that there can't be any non-leaf
976 : * pages behind leaf pages.
977 : */
978 0 : ptr = (GISTInsertStack *) palloc0(sizeof(GISTInsertStack));
979 0 : ptr->blkno = GistPageGetOpaque(page)->rightlink;
980 0 : ptr->downlinkoffnum = InvalidOffsetNumber;
981 0 : ptr->parent = top->parent;
982 :
983 0 : fifo = lcons(ptr, fifo);
984 : }
985 :
986 4 : maxoff = PageGetMaxOffsetNumber(page);
987 :
988 24 : for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
989 : {
990 22 : iid = PageGetItemId(page, i);
991 22 : idxtuple = (IndexTuple) PageGetItem(page, iid);
992 22 : blkno = ItemPointerGetBlockNumber(&(idxtuple->t_tid));
993 22 : if (blkno == child)
994 : {
995 : /* Found it! */
996 2 : UnlockReleaseBuffer(buffer);
997 2 : *downlinkoffnum = i;
998 2 : return top;
999 : }
1000 : else
1001 : {
1002 : /* Append this child to the list of pages to visit later */
1003 20 : ptr = (GISTInsertStack *) palloc0(sizeof(GISTInsertStack));
1004 20 : ptr->blkno = blkno;
1005 20 : ptr->downlinkoffnum = i;
1006 20 : ptr->parent = top;
1007 :
1008 20 : fifo = lappend(fifo, ptr);
1009 : }
1010 : }
1011 :
1012 2 : UnlockReleaseBuffer(buffer);
1013 : }
1014 :
1015 0 : elog(ERROR, "failed to re-find parent of a page in index \"%s\", block %u",
1016 : RelationGetRelationName(r), child);
1017 : return NULL; /* keep compiler quiet */
1018 : }
1019 :
1020 : /*
1021 : * Updates the stack so that child->parent is the correct parent of the
1022 : * child. child->parent must be exclusively locked on entry, and will
1023 : * remain so at exit, but it might not be the same page anymore.
1024 : */
1025 : static void
1026 24172 : gistFindCorrectParent(Relation r, GISTInsertStack *child, bool is_build)
1027 : {
1028 24172 : GISTInsertStack *parent = child->parent;
1029 : ItemId iid;
1030 : IndexTuple idxtuple;
1031 : OffsetNumber maxoff;
1032 : GISTInsertStack *ptr;
1033 :
1034 24172 : gistcheckpage(r, parent->buffer);
1035 24172 : parent->page = BufferGetPage(parent->buffer);
1036 24172 : maxoff = PageGetMaxOffsetNumber(parent->page);
1037 :
1038 : /* Check if the downlink is still where it was before */
1039 24172 : if (child->downlinkoffnum != InvalidOffsetNumber && child->downlinkoffnum <= maxoff)
1040 : {
1041 24130 : iid = PageGetItemId(parent->page, child->downlinkoffnum);
1042 24130 : idxtuple = (IndexTuple) PageGetItem(parent->page, iid);
1043 24130 : if (ItemPointerGetBlockNumber(&(idxtuple->t_tid)) == child->blkno)
1044 24130 : return; /* still there */
1045 : }
1046 :
1047 : /*
1048 : * The page has changed since we looked. During normal operation, every
1049 : * update of a page changes its LSN, so the LSN we memorized should have
1050 : * changed too.
1051 : *
1052 : * During index build, however, we don't WAL-log the changes until we have
1053 : * built the index, so the LSN doesn't change. There is no concurrent
1054 : * activity during index build, but we might have changed the parent
1055 : * ourselves.
1056 : *
1057 : * We will also get here if child->downlinkoffnum is invalid. That happens
1058 : * if 'parent' had been updated by an earlier call to this function on its
1059 : * grandchild, which had to move right.
1060 : */
1061 : Assert(parent->lsn != PageGetLSN(parent->page) || is_build ||
1062 : child->downlinkoffnum == InvalidOffsetNumber);
1063 :
1064 : /*
1065 : * Scan the page to re-find the downlink. If the page was split, it might
1066 : * have moved to a different page, so follow the right links until we find
1067 : * it.
1068 : */
1069 : while (true)
1070 22 : {
1071 : OffsetNumber i;
1072 :
1073 64 : maxoff = PageGetMaxOffsetNumber(parent->page);
1074 302 : for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
1075 : {
1076 278 : iid = PageGetItemId(parent->page, i);
1077 278 : idxtuple = (IndexTuple) PageGetItem(parent->page, iid);
1078 278 : if (ItemPointerGetBlockNumber(&(idxtuple->t_tid)) == child->blkno)
1079 : {
1080 : /* yes!!, found */
1081 40 : child->downlinkoffnum = i;
1082 40 : return;
1083 : }
1084 : }
1085 :
1086 24 : parent->blkno = GistPageGetOpaque(parent->page)->rightlink;
1087 24 : parent->downlinkoffnum = InvalidOffsetNumber;
1088 24 : UnlockReleaseBuffer(parent->buffer);
1089 24 : if (parent->blkno == InvalidBlockNumber)
1090 : {
1091 : /*
1092 : * End of chain and still didn't find parent. It's a very-very
1093 : * rare situation when the root was split.
1094 : */
1095 2 : break;
1096 : }
1097 22 : parent->buffer = ReadBuffer(r, parent->blkno);
1098 22 : LockBuffer(parent->buffer, GIST_EXCLUSIVE);
1099 22 : gistcheckpage(r, parent->buffer);
1100 22 : parent->page = BufferGetPage(parent->buffer);
1101 : }
1102 :
1103 : /*
1104 : * awful!!, we need search tree to find parent ... , but before we should
1105 : * release all old parent
1106 : */
1107 :
1108 2 : ptr = child->parent->parent; /* child->parent already released above */
1109 2 : while (ptr)
1110 : {
1111 0 : ReleaseBuffer(ptr->buffer);
1112 0 : ptr = ptr->parent;
1113 : }
1114 :
1115 : /* ok, find new path */
1116 2 : ptr = parent = gistFindPath(r, child->blkno, &child->downlinkoffnum);
1117 :
1118 : /* read all buffers as expected by caller */
1119 : /* note we don't lock them or gistcheckpage them here! */
1120 6 : while (ptr)
1121 : {
1122 4 : ptr->buffer = ReadBuffer(r, ptr->blkno);
1123 4 : ptr->page = BufferGetPage(ptr->buffer);
1124 4 : ptr = ptr->parent;
1125 : }
1126 :
1127 : /* install new chain of parents to stack */
1128 2 : child->parent = parent;
1129 :
1130 : /* make recursive call to normal processing */
1131 2 : LockBuffer(child->parent->buffer, GIST_EXCLUSIVE);
1132 2 : gistFindCorrectParent(r, child, is_build);
1133 : }
1134 :
1135 : /*
1136 : * Form a downlink pointer for the page in 'buf'.
1137 : */
1138 : static IndexTuple
1139 0 : gistformdownlink(Relation rel, Buffer buf, GISTSTATE *giststate,
1140 : GISTInsertStack *stack, bool is_build)
1141 : {
1142 0 : Page page = BufferGetPage(buf);
1143 : OffsetNumber maxoff;
1144 : OffsetNumber offset;
1145 0 : IndexTuple downlink = NULL;
1146 :
1147 0 : maxoff = PageGetMaxOffsetNumber(page);
1148 0 : for (offset = FirstOffsetNumber; offset <= maxoff; offset = OffsetNumberNext(offset))
1149 : {
1150 : IndexTuple ituple = (IndexTuple)
1151 0 : PageGetItem(page, PageGetItemId(page, offset));
1152 :
1153 0 : if (downlink == NULL)
1154 0 : downlink = CopyIndexTuple(ituple);
1155 : else
1156 : {
1157 : IndexTuple newdownlink;
1158 :
1159 0 : newdownlink = gistgetadjusted(rel, downlink, ituple,
1160 : giststate);
1161 0 : if (newdownlink)
1162 0 : downlink = newdownlink;
1163 : }
1164 : }
1165 :
1166 : /*
1167 : * If the page is completely empty, we can't form a meaningful downlink
1168 : * for it. But we have to insert a downlink for the page. Any key will do,
1169 : * as long as its consistent with the downlink of parent page, so that we
1170 : * can legally insert it to the parent. A minimal one that matches as few
1171 : * scans as possible would be best, to keep scans from doing useless work,
1172 : * but we don't know how to construct that. So we just use the downlink of
1173 : * the original page that was split - that's as far from optimal as it can
1174 : * get but will do..
1175 : */
1176 0 : if (!downlink)
1177 : {
1178 : ItemId iid;
1179 :
1180 0 : LockBuffer(stack->parent->buffer, GIST_EXCLUSIVE);
1181 0 : gistFindCorrectParent(rel, stack, is_build);
1182 0 : iid = PageGetItemId(stack->parent->page, stack->downlinkoffnum);
1183 0 : downlink = (IndexTuple) PageGetItem(stack->parent->page, iid);
1184 0 : downlink = CopyIndexTuple(downlink);
1185 0 : LockBuffer(stack->parent->buffer, GIST_UNLOCK);
1186 : }
1187 :
1188 0 : ItemPointerSetBlockNumber(&(downlink->t_tid), BufferGetBlockNumber(buf));
1189 0 : GistTupleSetValid(downlink);
1190 :
1191 0 : return downlink;
1192 : }
1193 :
1194 :
1195 : /*
1196 : * Complete the incomplete split of state->stack->page.
1197 : */
1198 : static void
1199 0 : gistfixsplit(GISTInsertState *state, GISTSTATE *giststate)
1200 : {
1201 0 : GISTInsertStack *stack = state->stack;
1202 : Buffer buf;
1203 : Page page;
1204 0 : List *splitinfo = NIL;
1205 :
1206 0 : ereport(LOG,
1207 : (errmsg("fixing incomplete split in index \"%s\", block %u",
1208 : RelationGetRelationName(state->r), stack->blkno)));
1209 :
1210 : Assert(GistFollowRight(stack->page));
1211 : Assert(OffsetNumberIsValid(stack->downlinkoffnum));
1212 :
1213 0 : buf = stack->buffer;
1214 :
1215 : /*
1216 : * Read the chain of split pages, following the rightlinks. Construct a
1217 : * downlink tuple for each page.
1218 : */
1219 : for (;;)
1220 0 : {
1221 0 : GISTPageSplitInfo *si = palloc(sizeof(GISTPageSplitInfo));
1222 : IndexTuple downlink;
1223 :
1224 0 : page = BufferGetPage(buf);
1225 :
1226 : /* Form the new downlink tuples to insert to parent */
1227 0 : downlink = gistformdownlink(state->r, buf, giststate, stack, state->is_build);
1228 :
1229 0 : si->buf = buf;
1230 0 : si->downlink = downlink;
1231 :
1232 0 : splitinfo = lappend(splitinfo, si);
1233 :
1234 0 : if (GistFollowRight(page))
1235 : {
1236 : /* lock next page */
1237 0 : buf = ReadBuffer(state->r, GistPageGetOpaque(page)->rightlink);
1238 0 : LockBuffer(buf, GIST_EXCLUSIVE);
1239 : }
1240 : else
1241 0 : break;
1242 : }
1243 :
1244 : /* Insert the downlinks */
1245 0 : gistfinishsplit(state, stack, giststate, splitinfo, false);
1246 0 : }
1247 :
1248 : /*
1249 : * Insert or replace a tuple in stack->buffer. If 'oldoffnum' is valid, the
1250 : * tuple at 'oldoffnum' is replaced, otherwise the tuple is inserted as new.
1251 : * 'stack' represents the path from the root to the page being updated.
1252 : *
1253 : * The caller must hold an exclusive lock on stack->buffer. The lock is still
1254 : * held on return, but the page might not contain the inserted tuple if the
1255 : * page was split. The function returns true if the page was split, false
1256 : * otherwise.
1257 : */
1258 : static bool
1259 1502178 : gistinserttuple(GISTInsertState *state, GISTInsertStack *stack,
1260 : GISTSTATE *giststate, IndexTuple tuple, OffsetNumber oldoffnum)
1261 : {
1262 1502178 : return gistinserttuples(state, stack, giststate, &tuple, 1, oldoffnum,
1263 : InvalidBuffer, InvalidBuffer, false, false);
1264 : }
1265 :
1266 : /* ----------------
1267 : * An extended workhorse version of gistinserttuple(). This version allows
1268 : * inserting multiple tuples, or replacing a single tuple with multiple tuples.
1269 : * This is used to recursively update the downlinks in the parent when a page
1270 : * is split.
1271 : *
1272 : * If leftchild and rightchild are valid, we're inserting/replacing the
1273 : * downlink for rightchild, and leftchild is its left sibling. We clear the
1274 : * F_FOLLOW_RIGHT flag and update NSN on leftchild, atomically with the
1275 : * insertion of the downlink.
1276 : *
1277 : * To avoid holding locks for longer than necessary, when recursing up the
1278 : * tree to update the parents, the locking is a bit peculiar here. On entry,
1279 : * the caller must hold an exclusive lock on stack->buffer, as well as
1280 : * leftchild and rightchild if given. On return:
1281 : *
1282 : * - Lock on stack->buffer is released, if 'unlockbuf' is true. The page is
1283 : * always kept pinned, however.
1284 : * - Lock on 'leftchild' is released, if 'unlockleftchild' is true. The page
1285 : * is kept pinned.
1286 : * - Lock and pin on 'rightchild' are always released.
1287 : *
1288 : * Returns 'true' if the page had to be split. Note that if the page was
1289 : * split, the inserted/updated tuples might've been inserted to a right
1290 : * sibling of stack->buffer instead of stack->buffer itself.
1291 : */
1292 : static bool
1293 1526348 : gistinserttuples(GISTInsertState *state, GISTInsertStack *stack,
1294 : GISTSTATE *giststate,
1295 : IndexTuple *tuples, int ntup, OffsetNumber oldoffnum,
1296 : Buffer leftchild, Buffer rightchild,
1297 : bool unlockbuf, bool unlockleftchild)
1298 : {
1299 : List *splitinfo;
1300 : bool is_split;
1301 :
1302 : /*
1303 : * Check for any rw conflicts (in serializable isolation level) just
1304 : * before we intend to modify the page
1305 : */
1306 1526348 : CheckForSerializableConflictIn(state->r, NULL, BufferGetBlockNumber(stack->buffer));
1307 :
1308 : /* Insert the tuple(s) to the page, splitting the page if necessary */
1309 1526336 : is_split = gistplacetopage(state->r, state->freespace, giststate,
1310 : stack->buffer,
1311 : tuples, ntup,
1312 : oldoffnum, NULL,
1313 : leftchild,
1314 : &splitinfo,
1315 : true,
1316 : state->heapRel,
1317 1526336 : state->is_build);
1318 :
1319 : /*
1320 : * Before recursing up in case the page was split, release locks on the
1321 : * child pages. We don't need to keep them locked when updating the
1322 : * parent.
1323 : */
1324 1526336 : if (BufferIsValid(rightchild))
1325 24170 : UnlockReleaseBuffer(rightchild);
1326 1526336 : if (BufferIsValid(leftchild) && unlockleftchild)
1327 5224 : LockBuffer(leftchild, GIST_UNLOCK);
1328 :
1329 : /*
1330 : * If we had to split, insert/update the downlinks in the parent. If the
1331 : * caller requested us to release the lock on stack->buffer, tell
1332 : * gistfinishsplit() to do that as soon as it's safe to do so. If we
1333 : * didn't have to split, release it ourselves.
1334 : */
1335 1526336 : if (splitinfo)
1336 24060 : gistfinishsplit(state, stack, giststate, splitinfo, unlockbuf);
1337 1502276 : else if (unlockbuf)
1338 18836 : LockBuffer(stack->buffer, GIST_UNLOCK);
1339 :
1340 1526336 : return is_split;
1341 : }
1342 :
1343 : /*
1344 : * Finish an incomplete split by inserting/updating the downlinks in parent
1345 : * page. 'splitinfo' contains all the child pages involved in the split,
1346 : * from left-to-right.
1347 : *
1348 : * On entry, the caller must hold a lock on stack->buffer and all the child
1349 : * pages in 'splitinfo'. If 'unlockbuf' is true, the lock on stack->buffer is
1350 : * released on return. The child pages are always unlocked and unpinned.
1351 : */
1352 : static void
1353 24060 : gistfinishsplit(GISTInsertState *state, GISTInsertStack *stack,
1354 : GISTSTATE *giststate, List *splitinfo, bool unlockbuf)
1355 : {
1356 : GISTPageSplitInfo *right;
1357 : GISTPageSplitInfo *left;
1358 : IndexTuple tuples[2];
1359 :
1360 : /* A split always contains at least two halves */
1361 : Assert(list_length(splitinfo) >= 2);
1362 :
1363 : /*
1364 : * We need to insert downlinks for each new page, and update the downlink
1365 : * for the original (leftmost) page in the split. Begin at the rightmost
1366 : * page, inserting one downlink at a time until there's only two pages
1367 : * left. Finally insert the downlink for the last new page and update the
1368 : * downlink for the original page as one operation.
1369 : */
1370 24060 : LockBuffer(stack->parent->buffer, GIST_EXCLUSIVE);
1371 :
1372 : /*
1373 : * Insert downlinks for the siblings from right to left, until there are
1374 : * only two siblings left.
1375 : */
1376 24170 : for (int pos = list_length(splitinfo) - 1; pos > 1; pos--)
1377 : {
1378 110 : right = (GISTPageSplitInfo *) list_nth(splitinfo, pos);
1379 110 : left = (GISTPageSplitInfo *) list_nth(splitinfo, pos - 1);
1380 :
1381 110 : gistFindCorrectParent(state->r, stack, state->is_build);
1382 110 : if (gistinserttuples(state, stack->parent, giststate,
1383 : &right->downlink, 1,
1384 : InvalidOffsetNumber,
1385 : left->buf, right->buf, false, false))
1386 : {
1387 : /*
1388 : * If the parent page was split, the existing downlink might have
1389 : * moved.
1390 : */
1391 12 : stack->downlinkoffnum = InvalidOffsetNumber;
1392 : }
1393 : /* gistinserttuples() released the lock on right->buf. */
1394 : }
1395 :
1396 24060 : right = (GISTPageSplitInfo *) lsecond(splitinfo);
1397 24060 : left = (GISTPageSplitInfo *) linitial(splitinfo);
1398 :
1399 : /*
1400 : * Finally insert downlink for the remaining right page and update the
1401 : * downlink for the original page to not contain the tuples that were
1402 : * moved to the new pages.
1403 : */
1404 24060 : tuples[0] = left->downlink;
1405 24060 : tuples[1] = right->downlink;
1406 24060 : gistFindCorrectParent(state->r, stack, state->is_build);
1407 24060 : (void) gistinserttuples(state, stack->parent, giststate,
1408 : tuples, 2,
1409 24060 : stack->downlinkoffnum,
1410 : left->buf, right->buf,
1411 : true, /* Unlock parent */
1412 : unlockbuf /* Unlock stack->buffer if caller
1413 : * wants that */
1414 : );
1415 :
1416 : /*
1417 : * The downlink might have moved when we updated it. Even if the page
1418 : * wasn't split, because gistinserttuples() implements updating the old
1419 : * tuple by removing and re-inserting it!
1420 : */
1421 24060 : stack->downlinkoffnum = InvalidOffsetNumber;
1422 :
1423 : Assert(left->buf == stack->buffer);
1424 :
1425 : /*
1426 : * If we split the page because we had to adjust the downlink on an
1427 : * internal page, while descending the tree for inserting a new tuple,
1428 : * then this might no longer be the correct page for the new tuple. The
1429 : * downlink to this page might not cover the new tuple anymore, it might
1430 : * need to go to the newly-created right sibling instead. Tell the caller
1431 : * to walk back up the stack, to re-check at the parent which page to
1432 : * insert to.
1433 : *
1434 : * Normally, the LSN-NSN interlock during the tree descend would also
1435 : * detect that a concurrent split happened (by ourselves), and cause us to
1436 : * retry at the parent. But that mechanism doesn't work during index
1437 : * build, because we don't do WAL-logging, and don't update LSNs, during
1438 : * index build.
1439 : */
1440 24060 : stack->retry_from_parent = true;
1441 24060 : }
1442 :
1443 : /*
1444 : * gistSplit -- split a page in the tree and fill struct
1445 : * used for XLOG and real writes buffers. Function is recursive, ie
1446 : * it will split page until keys will fit in every page.
1447 : */
1448 : SplitPageLayout *
1449 26742 : gistSplit(Relation r,
1450 : Page page,
1451 : IndexTuple *itup, /* contains compressed entry */
1452 : int len,
1453 : GISTSTATE *giststate)
1454 : {
1455 : IndexTuple *lvectup,
1456 : *rvectup;
1457 : GistSplitVector v;
1458 : int i;
1459 26742 : SplitPageLayout *res = NULL;
1460 :
1461 : /* this should never recurse very deeply, but better safe than sorry */
1462 26742 : check_stack_depth();
1463 :
1464 : /* there's no point in splitting an empty page */
1465 : Assert(len > 0);
1466 :
1467 : /*
1468 : * If a single tuple doesn't fit on a page, no amount of splitting will
1469 : * help.
1470 : */
1471 26742 : if (len == 1)
1472 0 : ereport(ERROR,
1473 : (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
1474 : errmsg("index row size %zu exceeds maximum %zu for index \"%s\"",
1475 : IndexTupleSize(itup[0]), GiSTPageSize,
1476 : RelationGetRelationName(r))));
1477 :
1478 26742 : memset(v.spl_lisnull, true,
1479 26742 : sizeof(bool) * giststate->nonLeafTupdesc->natts);
1480 26742 : memset(v.spl_risnull, true,
1481 26742 : sizeof(bool) * giststate->nonLeafTupdesc->natts);
1482 26742 : gistSplitByKey(r, page, itup, len, giststate, &v, 0);
1483 :
1484 : /* form left and right vector */
1485 26742 : lvectup = (IndexTuple *) palloc(sizeof(IndexTuple) * (len + 1));
1486 26742 : rvectup = (IndexTuple *) palloc(sizeof(IndexTuple) * (len + 1));
1487 :
1488 1145500 : for (i = 0; i < v.splitVector.spl_nleft; i++)
1489 1118758 : lvectup[i] = itup[v.splitVector.spl_left[i] - 1];
1490 :
1491 1277604 : for (i = 0; i < v.splitVector.spl_nright; i++)
1492 1250862 : rvectup[i] = itup[v.splitVector.spl_right[i] - 1];
1493 :
1494 : /* finalize splitting (may need another split) */
1495 26742 : if (!gistfitpage(rvectup, v.splitVector.spl_nright))
1496 : {
1497 698 : res = gistSplit(r, page, rvectup, v.splitVector.spl_nright, giststate);
1498 : }
1499 : else
1500 : {
1501 26044 : ROTATEDIST(res);
1502 26044 : res->block.num = v.splitVector.spl_nright;
1503 26044 : res->list = gistfillitupvec(rvectup, v.splitVector.spl_nright, &(res->lenlist));
1504 26044 : res->itup = gistFormTuple(giststate, r, v.spl_rattr, v.spl_risnull, false);
1505 : }
1506 :
1507 26742 : if (!gistfitpage(lvectup, v.splitVector.spl_nleft))
1508 : {
1509 : SplitPageLayout *resptr,
1510 : *subres;
1511 :
1512 496 : resptr = subres = gistSplit(r, page, lvectup, v.splitVector.spl_nleft, giststate);
1513 :
1514 : /* install on list's tail */
1515 1234 : while (resptr->next)
1516 738 : resptr = resptr->next;
1517 :
1518 496 : resptr->next = res;
1519 496 : res = subres;
1520 : }
1521 : else
1522 : {
1523 26246 : ROTATEDIST(res);
1524 26246 : res->block.num = v.splitVector.spl_nleft;
1525 26246 : res->list = gistfillitupvec(lvectup, v.splitVector.spl_nleft, &(res->lenlist));
1526 26246 : res->itup = gistFormTuple(giststate, r, v.spl_lattr, v.spl_lisnull, false);
1527 : }
1528 :
1529 26742 : return res;
1530 : }
1531 :
1532 : /*
1533 : * Create a GISTSTATE and fill it with information about the index
1534 : */
1535 : GISTSTATE *
1536 9372 : initGISTstate(Relation index)
1537 : {
1538 : GISTSTATE *giststate;
1539 : MemoryContext scanCxt;
1540 : MemoryContext oldCxt;
1541 : int i;
1542 :
1543 : /* safety check to protect fixed-size arrays in GISTSTATE */
1544 9372 : if (index->rd_att->natts > INDEX_MAX_KEYS)
1545 0 : elog(ERROR, "numberOfAttributes %d > %d",
1546 : index->rd_att->natts, INDEX_MAX_KEYS);
1547 :
1548 : /* Create the memory context that will hold the GISTSTATE */
1549 9372 : scanCxt = AllocSetContextCreate(CurrentMemoryContext,
1550 : "GiST scan context",
1551 : ALLOCSET_DEFAULT_SIZES);
1552 9372 : oldCxt = MemoryContextSwitchTo(scanCxt);
1553 :
1554 : /* Create and fill in the GISTSTATE */
1555 9372 : giststate = (GISTSTATE *) palloc(sizeof(GISTSTATE));
1556 :
1557 9372 : giststate->scanCxt = scanCxt;
1558 9372 : giststate->tempCxt = scanCxt; /* caller must change this if needed */
1559 9372 : giststate->leafTupdesc = index->rd_att;
1560 :
1561 : /*
1562 : * The truncated tupdesc for non-leaf index tuples, which doesn't contain
1563 : * the INCLUDE attributes.
1564 : *
1565 : * It is used to form tuples during tuple adjustment and page split.
1566 : * B-tree creates shortened tuple descriptor for every truncated tuple,
1567 : * because it is doing this less often: it does not have to form truncated
1568 : * tuples during page split. Also, B-tree is not adjusting tuples on
1569 : * internal pages the way GiST does.
1570 : */
1571 18744 : giststate->nonLeafTupdesc = CreateTupleDescTruncatedCopy(index->rd_att,
1572 9372 : IndexRelationGetNumberOfKeyAttributes(index));
1573 :
1574 24854 : for (i = 0; i < IndexRelationGetNumberOfKeyAttributes(index); i++)
1575 : {
1576 15482 : fmgr_info_copy(&(giststate->consistentFn[i]),
1577 15482 : index_getprocinfo(index, i + 1, GIST_CONSISTENT_PROC),
1578 : scanCxt);
1579 15482 : fmgr_info_copy(&(giststate->unionFn[i]),
1580 15482 : index_getprocinfo(index, i + 1, GIST_UNION_PROC),
1581 : scanCxt);
1582 :
1583 : /* opclasses are not required to provide a Compress method */
1584 15482 : if (OidIsValid(index_getprocid(index, i + 1, GIST_COMPRESS_PROC)))
1585 5390 : fmgr_info_copy(&(giststate->compressFn[i]),
1586 5390 : index_getprocinfo(index, i + 1, GIST_COMPRESS_PROC),
1587 : scanCxt);
1588 : else
1589 10092 : giststate->compressFn[i].fn_oid = InvalidOid;
1590 :
1591 : /* opclasses are not required to provide a Decompress method */
1592 15482 : if (OidIsValid(index_getprocid(index, i + 1, GIST_DECOMPRESS_PROC)))
1593 1622 : fmgr_info_copy(&(giststate->decompressFn[i]),
1594 1622 : index_getprocinfo(index, i + 1, GIST_DECOMPRESS_PROC),
1595 : scanCxt);
1596 : else
1597 13860 : giststate->decompressFn[i].fn_oid = InvalidOid;
1598 :
1599 15482 : fmgr_info_copy(&(giststate->penaltyFn[i]),
1600 15482 : index_getprocinfo(index, i + 1, GIST_PENALTY_PROC),
1601 : scanCxt);
1602 15482 : fmgr_info_copy(&(giststate->picksplitFn[i]),
1603 15482 : index_getprocinfo(index, i + 1, GIST_PICKSPLIT_PROC),
1604 : scanCxt);
1605 15482 : fmgr_info_copy(&(giststate->equalFn[i]),
1606 15482 : index_getprocinfo(index, i + 1, GIST_EQUAL_PROC),
1607 : scanCxt);
1608 :
1609 : /* opclasses are not required to provide a Distance method */
1610 15482 : if (OidIsValid(index_getprocid(index, i + 1, GIST_DISTANCE_PROC)))
1611 1914 : fmgr_info_copy(&(giststate->distanceFn[i]),
1612 1914 : index_getprocinfo(index, i + 1, GIST_DISTANCE_PROC),
1613 : scanCxt);
1614 : else
1615 13568 : giststate->distanceFn[i].fn_oid = InvalidOid;
1616 :
1617 : /* opclasses are not required to provide a Fetch method */
1618 15482 : if (OidIsValid(index_getprocid(index, i + 1, GIST_FETCH_PROC)))
1619 1378 : fmgr_info_copy(&(giststate->fetchFn[i]),
1620 1378 : index_getprocinfo(index, i + 1, GIST_FETCH_PROC),
1621 : scanCxt);
1622 : else
1623 14104 : giststate->fetchFn[i].fn_oid = InvalidOid;
1624 :
1625 : /*
1626 : * If the index column has a specified collation, we should honor that
1627 : * while doing comparisons. However, we may have a collatable storage
1628 : * type for a noncollatable indexed data type. If there's no index
1629 : * collation then specify default collation in case the support
1630 : * functions need collation. This is harmless if the support
1631 : * functions don't care about collation, so we just do it
1632 : * unconditionally. (We could alternatively call get_typcollation,
1633 : * but that seems like expensive overkill --- there aren't going to be
1634 : * any cases where a GiST storage type has a nondefault collation.)
1635 : */
1636 15482 : if (OidIsValid(index->rd_indcollation[i]))
1637 194 : giststate->supportCollation[i] = index->rd_indcollation[i];
1638 : else
1639 15288 : giststate->supportCollation[i] = DEFAULT_COLLATION_OID;
1640 : }
1641 :
1642 : /* No opclass information for INCLUDE attributes */
1643 9874 : for (; i < index->rd_att->natts; i++)
1644 : {
1645 502 : giststate->consistentFn[i].fn_oid = InvalidOid;
1646 502 : giststate->unionFn[i].fn_oid = InvalidOid;
1647 502 : giststate->compressFn[i].fn_oid = InvalidOid;
1648 502 : giststate->decompressFn[i].fn_oid = InvalidOid;
1649 502 : giststate->penaltyFn[i].fn_oid = InvalidOid;
1650 502 : giststate->picksplitFn[i].fn_oid = InvalidOid;
1651 502 : giststate->equalFn[i].fn_oid = InvalidOid;
1652 502 : giststate->distanceFn[i].fn_oid = InvalidOid;
1653 502 : giststate->fetchFn[i].fn_oid = InvalidOid;
1654 502 : giststate->supportCollation[i] = InvalidOid;
1655 : }
1656 :
1657 9372 : MemoryContextSwitchTo(oldCxt);
1658 :
1659 9372 : return giststate;
1660 : }
1661 :
1662 : void
1663 7164 : freeGISTstate(GISTSTATE *giststate)
1664 : {
1665 : /* It's sufficient to delete the scanCxt */
1666 7164 : MemoryContextDelete(giststate->scanCxt);
1667 7164 : }
1668 :
1669 : /*
1670 : * gistprunepage() -- try to remove LP_DEAD items from the given page.
1671 : * Function assumes that buffer is exclusively locked.
1672 : */
1673 : static void
1674 0 : gistprunepage(Relation rel, Page page, Buffer buffer, Relation heapRel)
1675 : {
1676 : OffsetNumber deletable[MaxIndexTuplesPerPage];
1677 0 : int ndeletable = 0;
1678 : OffsetNumber offnum,
1679 : maxoff;
1680 :
1681 : Assert(GistPageIsLeaf(page));
1682 :
1683 : /*
1684 : * Scan over all items to see which ones need to be deleted according to
1685 : * LP_DEAD flags.
1686 : */
1687 0 : maxoff = PageGetMaxOffsetNumber(page);
1688 0 : for (offnum = FirstOffsetNumber;
1689 0 : offnum <= maxoff;
1690 0 : offnum = OffsetNumberNext(offnum))
1691 : {
1692 0 : ItemId itemId = PageGetItemId(page, offnum);
1693 :
1694 0 : if (ItemIdIsDead(itemId))
1695 0 : deletable[ndeletable++] = offnum;
1696 : }
1697 :
1698 0 : if (ndeletable > 0)
1699 : {
1700 0 : TransactionId snapshotConflictHorizon = InvalidTransactionId;
1701 :
1702 0 : if (XLogStandbyInfoActive() && RelationNeedsWAL(rel))
1703 : snapshotConflictHorizon =
1704 0 : index_compute_xid_horizon_for_tuples(rel, heapRel, buffer,
1705 : deletable, ndeletable);
1706 :
1707 0 : START_CRIT_SECTION();
1708 :
1709 0 : PageIndexMultiDelete(page, deletable, ndeletable);
1710 :
1711 : /*
1712 : * Mark the page as not containing any LP_DEAD items. This is not
1713 : * certainly true (there might be some that have recently been marked,
1714 : * but weren't included in our target-item list), but it will almost
1715 : * always be true and it doesn't seem worth an additional page scan to
1716 : * check it. Remember that F_HAS_GARBAGE is only a hint anyway.
1717 : */
1718 0 : GistClearPageHasGarbage(page);
1719 :
1720 0 : MarkBufferDirty(buffer);
1721 :
1722 : /* XLOG stuff */
1723 0 : if (RelationNeedsWAL(rel))
1724 0 : {
1725 : XLogRecPtr recptr;
1726 :
1727 0 : recptr = gistXLogDelete(buffer,
1728 : deletable, ndeletable,
1729 : snapshotConflictHorizon,
1730 : heapRel);
1731 :
1732 0 : PageSetLSN(page, recptr);
1733 : }
1734 : else
1735 0 : PageSetLSN(page, gistGetFakeLSN(rel));
1736 :
1737 0 : END_CRIT_SECTION();
1738 : }
1739 :
1740 : /*
1741 : * Note: if we didn't find any LP_DEAD items, then the page's
1742 : * F_HAS_GARBAGE hint bit is falsely set. We do not bother expending a
1743 : * separate write to clear it, however. We will clear it when we split
1744 : * the page.
1745 : */
1746 0 : }
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