LCOV - code coverage report
Current view: top level - src/backend/access/gist - gist.c (source / functions) Coverage Total Hit
Test: PostgreSQL 20devel Lines: 79.6 % 530 422
Test Date: 2026-07-13 23:15:39 Functions: 82.4 % 17 14
Legend: Lines:     hit not hit
Branches: + taken - not taken # not executed
Branches: 66.3 % 300 199

             Branch data     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) 1996-2026, 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 = palloc0_object(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                 :       10948 : gisthandler(PG_FUNCTION_ARGS)
      60                 :             : {
      61                 :             :     static const IndexAmRoutine amroutine = {
      62                 :             :         .type = T_IndexAmRoutine,
      63                 :             :         .amstrategies = 0,
      64                 :             :         .amsupport = GISTNProcs,
      65                 :             :         .amoptsprocnum = GIST_OPTIONS_PROC,
      66                 :             :         .amcanorder = false,
      67                 :             :         .amcanorderbyop = true,
      68                 :             :         .amcanhash = false,
      69                 :             :         .amconsistentequality = false,
      70                 :             :         .amconsistentordering = false,
      71                 :             :         .amcanbackward = false,
      72                 :             :         .amcanunique = false,
      73                 :             :         .amcanmulticol = true,
      74                 :             :         .amoptionalkey = true,
      75                 :             :         .amsearcharray = false,
      76                 :             :         .amsearchnulls = true,
      77                 :             :         .amstorage = true,
      78                 :             :         .amclusterable = true,
      79                 :             :         .ampredlocks = true,
      80                 :             :         .amcanparallel = false,
      81                 :             :         .amcanbuildparallel = false,
      82                 :             :         .amcaninclude = true,
      83                 :             :         .amusemaintenanceworkmem = false,
      84                 :             :         .amsummarizing = false,
      85                 :             :         .amparallelvacuumoptions =
      86                 :             :         VACUUM_OPTION_PARALLEL_BULKDEL | VACUUM_OPTION_PARALLEL_COND_CLEANUP,
      87                 :             :         .amkeytype = InvalidOid,
      88                 :             : 
      89                 :             :         .ambuild = gistbuild,
      90                 :             :         .ambuildempty = gistbuildempty,
      91                 :             :         .aminsert = gistinsert,
      92                 :             :         .aminsertcleanup = NULL,
      93                 :             :         .ambulkdelete = gistbulkdelete,
      94                 :             :         .amvacuumcleanup = gistvacuumcleanup,
      95                 :             :         .amcanreturn = gistcanreturn,
      96                 :             :         .amcostestimate = gistcostestimate,
      97                 :             :         .amgettreeheight = NULL,
      98                 :             :         .amoptions = gistoptions,
      99                 :             :         .amproperty = gistproperty,
     100                 :             :         .ambuildphasename = NULL,
     101                 :             :         .amvalidate = gistvalidate,
     102                 :             :         .amadjustmembers = gistadjustmembers,
     103                 :             :         .ambeginscan = gistbeginscan,
     104                 :             :         .amrescan = gistrescan,
     105                 :             :         .amgettuple = gistgettuple,
     106                 :             :         .amgetbitmap = gistgetbitmap,
     107                 :             :         .amendscan = gistendscan,
     108                 :             :         .ammarkpos = NULL,
     109                 :             :         .amrestrpos = NULL,
     110                 :             :         .amestimateparallelscan = NULL,
     111                 :             :         .aminitparallelscan = NULL,
     112                 :             :         .amparallelrescan = NULL,
     113                 :             :         .amtranslatestrategy = NULL,
     114                 :             :         .amtranslatecmptype = gisttranslatecmptype,
     115                 :             :     };
     116                 :             : 
     117                 :       10948 :     PG_RETURN_POINTER(&amroutine);
     118                 :             : }
     119                 :             : 
     120                 :             : /*
     121                 :             :  * Create and return a temporary memory context for use by GiST. We
     122                 :             :  * _always_ invoke user-provided methods in a temporary memory
     123                 :             :  * context, so that memory leaks in those functions cannot cause
     124                 :             :  * problems. Also, we use some additional temporary contexts in the
     125                 :             :  * GiST code itself, to avoid the need to do some awkward manual
     126                 :             :  * memory management.
     127                 :             :  */
     128                 :             : MemoryContext
     129                 :        9617 : createTempGistContext(void)
     130                 :             : {
     131                 :        9617 :     return AllocSetContextCreate(CurrentMemoryContext,
     132                 :             :                                  "GiST temporary context",
     133                 :             :                                  ALLOCSET_DEFAULT_SIZES);
     134                 :             : }
     135                 :             : 
     136                 :             : /*
     137                 :             :  *  gistbuildempty() -- build an empty gist index in the initialization fork
     138                 :             :  */
     139                 :             : void
     140                 :           6 : gistbuildempty(Relation index)
     141                 :             : {
     142                 :             :     Buffer      buffer;
     143                 :             : 
     144                 :             :     /* Initialize the root page */
     145                 :           6 :     buffer = ExtendBufferedRel(BMR_REL(index), INIT_FORKNUM, NULL,
     146                 :             :                                EB_SKIP_EXTENSION_LOCK | EB_LOCK_FIRST);
     147                 :             : 
     148                 :             :     /* Initialize and xlog buffer */
     149                 :           6 :     START_CRIT_SECTION();
     150                 :           6 :     GISTInitBuffer(buffer, F_LEAF);
     151                 :           6 :     MarkBufferDirty(buffer);
     152                 :           6 :     log_newpage_buffer(buffer, true);
     153                 :           6 :     END_CRIT_SECTION();
     154                 :             : 
     155                 :             :     /* Unlock and release the buffer */
     156                 :           6 :     UnlockReleaseBuffer(buffer);
     157                 :           6 : }
     158                 :             : 
     159                 :             : /*
     160                 :             :  *  gistinsert -- wrapper for GiST tuple insertion.
     161                 :             :  *
     162                 :             :  *    This is the public interface routine for tuple insertion in GiSTs.
     163                 :             :  *    It doesn't do any work; just locks the relation and passes the buck.
     164                 :             :  */
     165                 :             : bool
     166                 :      190224 : gistinsert(Relation r, Datum *values, bool *isnull,
     167                 :             :            ItemPointer ht_ctid, Relation heapRel,
     168                 :             :            IndexUniqueCheck checkUnique,
     169                 :             :            bool indexUnchanged,
     170                 :             :            IndexInfo *indexInfo)
     171                 :             : {
     172                 :      190224 :     GISTSTATE  *giststate = (GISTSTATE *) indexInfo->ii_AmCache;
     173                 :             :     IndexTuple  itup;
     174                 :             :     MemoryContext oldCxt;
     175                 :             : 
     176                 :             :     /* Initialize GISTSTATE cache if first call in this statement */
     177         [ +  + ]:      190224 :     if (giststate == NULL)
     178                 :             :     {
     179                 :        1929 :         oldCxt = MemoryContextSwitchTo(indexInfo->ii_Context);
     180                 :        1929 :         giststate = initGISTstate(r);
     181                 :        1929 :         giststate->tempCxt = createTempGistContext();
     182                 :        1929 :         indexInfo->ii_AmCache = giststate;
     183                 :        1929 :         MemoryContextSwitchTo(oldCxt);
     184                 :             :     }
     185                 :             : 
     186                 :      190224 :     oldCxt = MemoryContextSwitchTo(giststate->tempCxt);
     187                 :             : 
     188                 :      190224 :     itup = gistFormTuple(giststate, r, values, isnull, true);
     189                 :      190223 :     itup->t_tid = *ht_ctid;
     190                 :             : 
     191                 :      190223 :     gistdoinsert(r, itup, 0, giststate, heapRel, false);
     192                 :             : 
     193                 :             :     /* cleanup */
     194                 :      190217 :     MemoryContextSwitchTo(oldCxt);
     195                 :      190217 :     MemoryContextReset(giststate->tempCxt);
     196                 :             : 
     197                 :      190217 :     return false;
     198                 :             : }
     199                 :             : 
     200                 :             : 
     201                 :             : /*
     202                 :             :  * Place tuples from 'itup' to 'buffer'. If 'oldoffnum' is valid, the tuple
     203                 :             :  * at that offset is atomically removed along with inserting the new tuples.
     204                 :             :  * This is used to replace a tuple with a new one.
     205                 :             :  *
     206                 :             :  * If 'leftchildbuf' is valid, we're inserting the downlink for the page
     207                 :             :  * to the right of 'leftchildbuf', or updating the downlink for 'leftchildbuf'.
     208                 :             :  * F_FOLLOW_RIGHT flag on 'leftchildbuf' is cleared and NSN is set.
     209                 :             :  *
     210                 :             :  * If 'markfollowright' is true and the page is split, the left child is
     211                 :             :  * marked with F_FOLLOW_RIGHT flag. That is the normal case. During buffered
     212                 :             :  * index build, however, there is no concurrent access and the page splitting
     213                 :             :  * is done in a slightly simpler fashion, and false is passed.
     214                 :             :  *
     215                 :             :  * If there is not enough room on the page, it is split. All the split
     216                 :             :  * pages are kept pinned and locked and returned in *splitinfo, the caller
     217                 :             :  * is responsible for inserting the downlinks for them. However, if
     218                 :             :  * 'buffer' is the root page and it needs to be split, gistplacetopage()
     219                 :             :  * performs the split as one atomic operation, and *splitinfo is set to NIL.
     220                 :             :  * In that case, we continue to hold the root page locked, and the child
     221                 :             :  * pages are released; note that new tuple(s) are *not* on the root page
     222                 :             :  * but in one of the new child pages.
     223                 :             :  *
     224                 :             :  * If 'newblkno' is not NULL, returns the block number of page the first
     225                 :             :  * new/updated tuple was inserted to. Usually it's the given page, but could
     226                 :             :  * be its right sibling if the page was split.
     227                 :             :  *
     228                 :             :  * Returns 'true' if the page was split, 'false' otherwise.
     229                 :             :  */
     230                 :             : bool
     231                 :     1020126 : gistplacetopage(Relation rel, Size freespace, GISTSTATE *giststate,
     232                 :             :                 Buffer buffer,
     233                 :             :                 IndexTuple *itup, int ntup, OffsetNumber oldoffnum,
     234                 :             :                 BlockNumber *newblkno,
     235                 :             :                 Buffer leftchildbuf,
     236                 :             :                 List **splitinfo,
     237                 :             :                 bool markfollowright,
     238                 :             :                 Relation heapRel,
     239                 :             :                 bool is_build)
     240                 :             : {
     241                 :     1020126 :     BlockNumber blkno = BufferGetBlockNumber(buffer);
     242                 :     1020126 :     Page        page = BufferGetPage(buffer);
     243                 :     1020126 :     bool        is_leaf = (GistPageIsLeaf(page)) ? true : false;
     244                 :             :     XLogRecPtr  recptr;
     245                 :             :     bool        is_split;
     246                 :             : 
     247                 :             :     /*
     248                 :             :      * Refuse to modify a page that's incompletely split. This should not
     249                 :             :      * happen because we finish any incomplete splits while we walk down the
     250                 :             :      * tree. However, it's remotely possible that another concurrent inserter
     251                 :             :      * splits a parent page, and errors out before completing the split. We
     252                 :             :      * will just throw an error in that case, and leave any split we had in
     253                 :             :      * progress unfinished too. The next insert that comes along will clean up
     254                 :             :      * the mess.
     255                 :             :      */
     256         [ -  + ]:     1020126 :     if (GistFollowRight(page))
     257         [ #  # ]:           0 :         elog(ERROR, "concurrent GiST page split was incomplete");
     258                 :             : 
     259                 :             :     /* should never try to insert to a deleted page */
     260                 :             :     Assert(!GistPageIsDeleted(page));
     261                 :             : 
     262                 :     1020126 :     *splitinfo = NIL;
     263                 :             : 
     264                 :             :     /*
     265                 :             :      * if isupdate, remove old key: This node's key has been modified, either
     266                 :             :      * because a child split occurred or because we needed to adjust our key
     267                 :             :      * for an insert in a child node. Therefore, remove the old version of
     268                 :             :      * this node's key.
     269                 :             :      *
     270                 :             :      * for WAL replay, in the non-split case we handle this by setting up a
     271                 :             :      * one-element todelete array; in the split case, it's handled implicitly
     272                 :             :      * because the tuple vector passed to gistSplit won't include this tuple.
     273                 :             :      */
     274                 :     1020126 :     is_split = gistnospace(page, itup, ntup, oldoffnum, freespace);
     275                 :             : 
     276                 :             :     /*
     277                 :             :      * If leaf page is full, try at first to delete dead tuples. And then
     278                 :             :      * check again.
     279                 :             :      */
     280   [ +  +  +  +  :     1020126 :     if (is_split && GistPageIsLeaf(page) && GistPageHasGarbage(page))
                   -  + ]
     281                 :             :     {
     282                 :           0 :         gistprunepage(rel, page, buffer, heapRel);
     283                 :           0 :         is_split = gistnospace(page, itup, ntup, oldoffnum, freespace);
     284                 :             :     }
     285                 :             : 
     286         [ +  + ]:     1020126 :     if (is_split)
     287                 :             :     {
     288                 :             :         /* no space for insertion */
     289                 :             :         IndexTuple *itvec;
     290                 :             :         int         tlen;
     291                 :       14283 :         SplitPageLayout *dist = NULL,
     292                 :             :                    *ptr;
     293                 :       14283 :         BlockNumber oldrlink = InvalidBlockNumber;
     294                 :       14283 :         GistNSN     oldnsn = InvalidXLogRecPtr;
     295                 :             :         SplitPageLayout rootpg;
     296                 :             :         bool        is_rootsplit;
     297                 :             :         int         npage;
     298                 :             : 
     299                 :       14283 :         is_rootsplit = (blkno == GIST_ROOT_BLKNO);
     300                 :             : 
     301                 :             :         /*
     302                 :             :          * Form index tuples vector to split. If we're replacing an old tuple,
     303                 :             :          * remove the old version from the vector.
     304                 :             :          */
     305                 :       14283 :         itvec = gistextractpage(page, &tlen);
     306   [ +  +  +  -  :       14283 :         if (OffsetNumberIsValid(oldoffnum))
                   +  + ]
     307                 :             :         {
     308                 :             :             /* on inner page we should remove old tuple */
     309                 :        2770 :             int         pos = oldoffnum - FirstOffsetNumber;
     310                 :             : 
     311                 :        2770 :             tlen--;
     312         [ +  + ]:        2770 :             if (pos != tlen)
     313                 :        1768 :                 memmove(itvec + pos, itvec + pos + 1, sizeof(IndexTuple) * (tlen - pos));
     314                 :             :         }
     315                 :       14283 :         itvec = gistjoinvector(itvec, &tlen, itup, ntup);
     316                 :       14283 :         dist = gistSplit(rel, page, itvec, tlen, giststate);
     317                 :             : 
     318                 :             :         /*
     319                 :             :          * Check that split didn't produce too many pages.
     320                 :             :          */
     321                 :       14283 :         npage = 0;
     322         [ +  + ]:       42906 :         for (ptr = dist; ptr; ptr = ptr->next)
     323                 :       28623 :             npage++;
     324                 :             :         /* in a root split, we'll add one more page to the list below */
     325         [ +  + ]:       14283 :         if (is_rootsplit)
     326                 :         203 :             npage++;
     327         [ -  + ]:       14283 :         if (npage > GIST_MAX_SPLIT_PAGES)
     328         [ #  # ]:           0 :             elog(ERROR, "GiST page split into too many halves (%d, maximum %d)",
     329                 :             :                  npage, GIST_MAX_SPLIT_PAGES);
     330                 :             : 
     331                 :             :         /*
     332                 :             :          * Set up pages to work with. Allocate new buffers for all but the
     333                 :             :          * leftmost page. The original page becomes the new leftmost page, and
     334                 :             :          * is just replaced with the new contents.
     335                 :             :          *
     336                 :             :          * For a root-split, allocate new buffers for all child pages, the
     337                 :             :          * original page is overwritten with new root page containing
     338                 :             :          * downlinks to the new child pages.
     339                 :             :          */
     340                 :       14283 :         ptr = dist;
     341         [ +  + ]:       14283 :         if (!is_rootsplit)
     342                 :             :         {
     343                 :             :             /* save old rightlink and NSN */
     344                 :       14080 :             oldrlink = GistPageGetOpaque(page)->rightlink;
     345                 :       14080 :             oldnsn = GistPageGetNSN(page);
     346                 :             : 
     347                 :       14080 :             dist->buffer = buffer;
     348                 :       14080 :             dist->block.blkno = BufferGetBlockNumber(buffer);
     349                 :       14080 :             dist->page = PageGetTempPageCopySpecial(BufferGetPage(buffer));
     350                 :             : 
     351                 :             :             /* clean all flags except F_LEAF */
     352                 :       14080 :             GistPageGetOpaque(dist->page)->flags = (is_leaf) ? F_LEAF : 0;
     353                 :             : 
     354                 :       14080 :             ptr = ptr->next;
     355                 :             :         }
     356         [ +  + ]:       28826 :         for (; ptr; ptr = ptr->next)
     357                 :             :         {
     358                 :             :             /* Allocate new page */
     359                 :       14543 :             ptr->buffer = gistNewBuffer(rel, heapRel);
     360                 :       14543 :             GISTInitBuffer(ptr->buffer, (is_leaf) ? F_LEAF : 0);
     361                 :       14543 :             ptr->page = BufferGetPage(ptr->buffer);
     362                 :       14543 :             ptr->block.blkno = BufferGetBlockNumber(ptr->buffer);
     363                 :       14543 :             PredicateLockPageSplit(rel,
     364                 :             :                                    BufferGetBlockNumber(buffer),
     365                 :             :                                    BufferGetBlockNumber(ptr->buffer));
     366                 :             :         }
     367                 :             : 
     368                 :             :         /*
     369                 :             :          * Now that we know which blocks the new pages go to, set up downlink
     370                 :             :          * tuples to point to them.
     371                 :             :          */
     372         [ +  + ]:       42906 :         for (ptr = dist; ptr; ptr = ptr->next)
     373                 :             :         {
     374                 :       28623 :             ItemPointerSetBlockNumber(&(ptr->itup->t_tid), ptr->block.blkno);
     375                 :       28623 :             GistTupleSetValid(ptr->itup);
     376                 :             :         }
     377                 :             : 
     378                 :             :         /*
     379                 :             :          * If this is a root split, we construct the new root page with the
     380                 :             :          * downlinks here directly, instead of requiring the caller to insert
     381                 :             :          * them. Add the new root page to the list along with the child pages.
     382                 :             :          */
     383         [ +  + ]:       14283 :         if (is_rootsplit)
     384                 :             :         {
     385                 :             :             IndexTuple *downlinks;
     386                 :         203 :             int         ndownlinks = 0;
     387                 :             :             int         i;
     388                 :             : 
     389                 :         203 :             rootpg.buffer = buffer;
     390                 :         203 :             rootpg.page = PageGetTempPageCopySpecial(BufferGetPage(rootpg.buffer));
     391                 :         203 :             GistPageGetOpaque(rootpg.page)->flags = 0;
     392                 :             : 
     393                 :             :             /* Prepare a vector of all the downlinks */
     394         [ +  + ]:         612 :             for (ptr = dist; ptr; ptr = ptr->next)
     395                 :         409 :                 ndownlinks++;
     396                 :         203 :             downlinks = palloc_array(IndexTuple, ndownlinks);
     397         [ +  + ]:         612 :             for (i = 0, ptr = dist; ptr; ptr = ptr->next)
     398                 :         409 :                 downlinks[i++] = ptr->itup;
     399                 :             : 
     400                 :         203 :             rootpg.block.blkno = GIST_ROOT_BLKNO;
     401                 :         203 :             rootpg.block.num = ndownlinks;
     402                 :         203 :             rootpg.list = gistfillitupvec(downlinks, ndownlinks,
     403                 :             :                                           &(rootpg.lenlist));
     404                 :         203 :             rootpg.itup = NULL;
     405                 :             : 
     406                 :         203 :             rootpg.next = dist;
     407                 :         203 :             dist = &rootpg;
     408                 :             :         }
     409                 :             :         else
     410                 :             :         {
     411                 :             :             /* Prepare split-info to be returned to caller */
     412         [ +  + ]:       42294 :             for (ptr = dist; ptr; ptr = ptr->next)
     413                 :             :             {
     414                 :       28214 :                 GISTPageSplitInfo *si = palloc_object(GISTPageSplitInfo);
     415                 :             : 
     416                 :       28214 :                 si->buf = ptr->buffer;
     417                 :       28214 :                 si->downlink = ptr->itup;
     418                 :       28214 :                 *splitinfo = lappend(*splitinfo, si);
     419                 :             :             }
     420                 :             :         }
     421                 :             : 
     422                 :             :         /*
     423                 :             :          * Fill all pages. All the pages are new, ie. freshly allocated empty
     424                 :             :          * pages, or a temporary copy of the old page.
     425                 :             :          */
     426         [ +  + ]:       43109 :         for (ptr = dist; ptr; ptr = ptr->next)
     427                 :             :         {
     428                 :       28826 :             char       *data = (char *) (ptr->list);
     429                 :             : 
     430         [ +  + ]:     1111774 :             for (int i = 0; i < ptr->block.num; i++)
     431                 :             :             {
     432                 :     1082948 :                 IndexTuple  thistup = (IndexTuple) data;
     433                 :             : 
     434         [ -  + ]:     1082948 :                 if (PageAddItem(ptr->page, data, IndexTupleSize(thistup), i + FirstOffsetNumber, false, false) == InvalidOffsetNumber)
     435         [ #  # ]:           0 :                     elog(ERROR, "failed to add item to index page in \"%s\"", RelationGetRelationName(rel));
     436                 :             : 
     437                 :             :                 /*
     438                 :             :                  * If this is the first inserted/updated tuple, let the caller
     439                 :             :                  * know which page it landed on.
     440                 :             :                  */
     441   [ +  +  +  + ]:     1082948 :                 if (newblkno && ItemPointerEquals(&thistup->t_tid, &(*itup)->t_tid))
     442                 :         516 :                     *newblkno = ptr->block.blkno;
     443                 :             : 
     444                 :     1082948 :                 data += IndexTupleSize(thistup);
     445                 :             :             }
     446                 :             : 
     447                 :             :             /* Set up rightlinks */
     448   [ +  +  +  + ]:       28826 :             if (ptr->next && ptr->block.blkno != GIST_ROOT_BLKNO)
     449                 :       28680 :                 GistPageGetOpaque(ptr->page)->rightlink =
     450                 :       14340 :                     ptr->next->block.blkno;
     451                 :             :             else
     452                 :       14486 :                 GistPageGetOpaque(ptr->page)->rightlink = oldrlink;
     453                 :             : 
     454                 :             :             /*
     455                 :             :              * Mark the all but the right-most page with the follow-right
     456                 :             :              * flag. It will be cleared as soon as the downlink is inserted
     457                 :             :              * into the parent, but this ensures that if we error out before
     458                 :             :              * that, the index is still consistent. (in buffering build mode,
     459                 :             :              * any error will abort the index build anyway, so this is not
     460                 :             :              * needed.)
     461                 :             :              */
     462   [ +  +  +  +  :       28826 :             if (ptr->next && !is_rootsplit && markfollowright)
                   +  + ]
     463                 :       13622 :                 GistMarkFollowRight(ptr->page);
     464                 :             :             else
     465                 :       15204 :                 GistClearFollowRight(ptr->page);
     466                 :             : 
     467                 :             :             /*
     468                 :             :              * Copy the NSN of the original page to all pages. The
     469                 :             :              * F_FOLLOW_RIGHT flags ensure that scans will follow the
     470                 :             :              * rightlinks until the downlinks are inserted.
     471                 :             :              */
     472                 :       28826 :             GistPageSetNSN(ptr->page, oldnsn);
     473                 :             :         }
     474                 :             : 
     475                 :             :         /*
     476                 :             :          * gistXLogSplit() needs to WAL log a lot of pages, prepare WAL
     477                 :             :          * insertion for that. NB: The number of pages and data segments
     478                 :             :          * specified here must match the calculations in gistXLogSplit()!
     479                 :             :          */
     480   [ +  +  +  +  :       14283 :         if (!is_build && RelationNeedsWAL(rel))
          -  +  -  -  -  
                      - ]
     481                 :        2184 :             XLogEnsureRecordSpace(npage, 1 + npage * 2);
     482                 :             : 
     483                 :       14283 :         START_CRIT_SECTION();
     484                 :             : 
     485                 :             :         /*
     486                 :             :          * Must mark buffers dirty before XLogInsert, even though we'll still
     487                 :             :          * be changing their opaque fields below.
     488                 :             :          */
     489         [ +  + ]:       43109 :         for (ptr = dist; ptr; ptr = ptr->next)
     490                 :       28826 :             MarkBufferDirty(ptr->buffer);
     491         [ +  + ]:       14283 :         if (BufferIsValid(leftchildbuf))
     492                 :        2679 :             MarkBufferDirty(leftchildbuf);
     493                 :             : 
     494                 :             :         /*
     495                 :             :          * The first page in the chain was a temporary working copy meant to
     496                 :             :          * replace the old page. Copy it over the old page.
     497                 :             :          */
     498                 :       14283 :         PageRestoreTempPage(dist->page, BufferGetPage(dist->buffer));
     499                 :       14283 :         dist->page = BufferGetPage(dist->buffer);
     500                 :             : 
     501                 :             :         /*
     502                 :             :          * Write the WAL record.
     503                 :             :          *
     504                 :             :          * If we're building a new index, however, we don't WAL-log changes
     505                 :             :          * yet. The LSN-NSN interlock between parent and child requires that
     506                 :             :          * LSNs never move backwards, so set the LSNs to a value that's
     507                 :             :          * smaller than any real or fake unlogged LSN that might be generated
     508                 :             :          * later. (There can't be any concurrent scans during index build, so
     509                 :             :          * we don't need to be able to detect concurrent splits yet.)
     510                 :             :          */
     511         [ +  + ]:       14283 :         if (is_build)
     512                 :       12095 :             recptr = GistBuildLSN;
     513                 :             :         else
     514                 :             :         {
     515   [ +  +  -  +  :        2188 :             if (RelationNeedsWAL(rel))
             -  -  -  - ]
     516                 :        2184 :                 recptr = gistXLogSplit(is_leaf,
     517                 :             :                                        dist, oldrlink, oldnsn, leftchildbuf,
     518                 :             :                                        markfollowright);
     519                 :             :             else
     520                 :           4 :                 recptr = XLogGetFakeLSN(rel);
     521                 :             :         }
     522                 :             : 
     523         [ +  + ]:       43109 :         for (ptr = dist; ptr; ptr = ptr->next)
     524                 :       28826 :             PageSetLSN(ptr->page, recptr);
     525                 :             : 
     526                 :             :         /*
     527                 :             :          * Return the new child buffers to the caller.
     528                 :             :          *
     529                 :             :          * If this was a root split, we've already inserted the downlink
     530                 :             :          * pointers, in the form of a new root page. Therefore we can release
     531                 :             :          * all the new buffers, and keep just the root page locked.
     532                 :             :          */
     533         [ +  + ]:       14283 :         if (is_rootsplit)
     534                 :             :         {
     535         [ +  + ]:         612 :             for (ptr = dist->next; ptr; ptr = ptr->next)
     536                 :         409 :                 UnlockReleaseBuffer(ptr->buffer);
     537                 :             :         }
     538                 :             :     }
     539                 :             :     else
     540                 :             :     {
     541                 :             :         /*
     542                 :             :          * Enough space.  We always get here if ntup==0.
     543                 :             :          */
     544                 :     1005843 :         START_CRIT_SECTION();
     545                 :             : 
     546                 :             :         /*
     547                 :             :          * Delete old tuple if any, then insert new tuple(s) if any.  If
     548                 :             :          * possible, use the fast path of PageIndexTupleOverwrite.
     549                 :             :          */
     550   [ +  +  +  -  :     1005843 :         if (OffsetNumberIsValid(oldoffnum))
                   +  + ]
     551                 :             :         {
     552         [ +  + ]:      460499 :             if (ntup == 1)
     553                 :             :             {
     554                 :             :                 /* One-for-one replacement, so use PageIndexTupleOverwrite */
     555         [ -  + ]:      449109 :                 if (!PageIndexTupleOverwrite(page, oldoffnum, *itup, IndexTupleSize(*itup)))
     556         [ #  # ]:           0 :                     elog(ERROR, "failed to add item to index page in \"%s\"",
     557                 :             :                          RelationGetRelationName(rel));
     558                 :             :             }
     559                 :             :             else
     560                 :             :             {
     561                 :             :                 /* Delete old, then append new tuple(s) to page */
     562                 :       11390 :                 PageIndexTupleDelete(page, oldoffnum);
     563                 :       11390 :                 gistfillbuffer(page, itup, ntup, InvalidOffsetNumber);
     564                 :             :             }
     565                 :             :         }
     566                 :             :         else
     567                 :             :         {
     568                 :             :             /* Just append new tuples at the end of the page */
     569                 :      545344 :             gistfillbuffer(page, itup, ntup, InvalidOffsetNumber);
     570                 :             :         }
     571                 :             : 
     572                 :     1005843 :         MarkBufferDirty(buffer);
     573                 :             : 
     574         [ +  + ]:     1005843 :         if (BufferIsValid(leftchildbuf))
     575                 :       10943 :             MarkBufferDirty(leftchildbuf);
     576                 :             : 
     577         [ +  + ]:     1005843 :         if (is_build)
     578                 :      699623 :             recptr = GistBuildLSN;
     579                 :             :         else
     580                 :             :         {
     581   [ +  +  +  +  :      306220 :             if (RelationNeedsWAL(rel))
             +  -  +  - ]
     582                 :      306168 :             {
     583                 :      306168 :                 OffsetNumber ndeloffs = 0,
     584                 :             :                             deloffs[1];
     585                 :             : 
     586   [ +  +  +  -  :      306168 :                 if (OffsetNumberIsValid(oldoffnum))
                   +  + ]
     587                 :             :                 {
     588                 :      118175 :                     deloffs[0] = oldoffnum;
     589                 :      118175 :                     ndeloffs = 1;
     590                 :             :                 }
     591                 :             : 
     592                 :      306168 :                 recptr = gistXLogUpdate(buffer,
     593                 :             :                                         deloffs, ndeloffs, itup, ntup,
     594                 :             :                                         leftchildbuf);
     595                 :             :             }
     596                 :             :             else
     597                 :          52 :                 recptr = XLogGetFakeLSN(rel);
     598                 :             :         }
     599                 :     1005843 :         PageSetLSN(page, recptr);
     600                 :             : 
     601         [ +  + ]:     1005843 :         if (newblkno)
     602                 :       69580 :             *newblkno = blkno;
     603                 :             :     }
     604                 :             : 
     605                 :             :     /*
     606                 :             :      * If we inserted the downlink for a child page, set NSN and clear
     607                 :             :      * F_FOLLOW_RIGHT flag on the left child, so that concurrent scans know to
     608                 :             :      * follow the rightlink if and only if they looked at the parent page
     609                 :             :      * before we inserted the downlink.
     610                 :             :      *
     611                 :             :      * Note that we do this *after* writing the WAL record. That means that
     612                 :             :      * the possible full page image in the WAL record does not include these
     613                 :             :      * changes, and they must be replayed even if the page is restored from
     614                 :             :      * the full page image. There's a chicken-and-egg problem: if we updated
     615                 :             :      * the child pages first, we wouldn't know the recptr of the WAL record
     616                 :             :      * we're about to write.
     617                 :             :      */
     618         [ +  + ]:     1020126 :     if (BufferIsValid(leftchildbuf))
     619                 :             :     {
     620                 :       13622 :         Page        leftpg = BufferGetPage(leftchildbuf);
     621                 :             : 
     622                 :       13622 :         GistPageSetNSN(leftpg, recptr);
     623                 :       13622 :         GistClearFollowRight(leftpg);
     624                 :             : 
     625                 :       13622 :         PageSetLSN(leftpg, recptr);
     626                 :             :     }
     627                 :             : 
     628                 :     1020126 :     END_CRIT_SECTION();
     629                 :             : 
     630                 :     1020126 :     return is_split;
     631                 :             : }
     632                 :             : 
     633                 :             : /*
     634                 :             :  * Workhorse routine for doing insertion into a GiST index. Note that
     635                 :             :  * this routine assumes it is invoked in a short-lived memory context,
     636                 :             :  * so it does not bother releasing palloc'd allocations.
     637                 :             :  */
     638                 :             : void
     639                 :      533189 : gistdoinsert(Relation r, IndexTuple itup, Size freespace,
     640                 :             :              GISTSTATE *giststate, Relation heapRel, bool is_build)
     641                 :             : {
     642                 :             :     ItemId      iid;
     643                 :             :     IndexTuple  idxtuple;
     644                 :             :     GISTInsertStack firststack;
     645                 :             :     GISTInsertStack *stack;
     646                 :             :     GISTInsertState state;
     647                 :      533189 :     bool        xlocked = false;
     648                 :             : 
     649                 :      533189 :     memset(&state, 0, sizeof(GISTInsertState));
     650                 :      533189 :     state.freespace = freespace;
     651                 :      533189 :     state.r = r;
     652                 :      533189 :     state.heapRel = heapRel;
     653                 :      533189 :     state.is_build = is_build;
     654                 :             : 
     655                 :             :     /* Start from the root */
     656                 :      533189 :     firststack.blkno = GIST_ROOT_BLKNO;
     657                 :      533189 :     firststack.lsn = InvalidXLogRecPtr;
     658                 :      533189 :     firststack.retry_from_parent = false;
     659                 :      533189 :     firststack.parent = NULL;
     660                 :      533189 :     firststack.downlinkoffnum = InvalidOffsetNumber;
     661                 :      533189 :     state.stack = stack = &firststack;
     662                 :             : 
     663                 :             :     /*
     664                 :             :      * Walk down along the path of smallest penalty, updating the parent
     665                 :             :      * pointers with the key we're inserting as we go. If we crash in the
     666                 :             :      * middle, the tree is consistent, although the possible parent updates
     667                 :             :      * were a waste.
     668                 :             :      */
     669                 :             :     for (;;)
     670                 :             :     {
     671                 :             :         /*
     672                 :             :          * If we split an internal page while descending the tree, we have to
     673                 :             :          * retry at the parent. (Normally, the LSN-NSN interlock below would
     674                 :             :          * also catch this and cause us to retry. But LSNs are not updated
     675                 :             :          * during index build.)
     676                 :             :          */
     677         [ +  + ]:     1212958 :         while (stack->retry_from_parent)
     678                 :             :         {
     679         [ -  + ]:         179 :             if (xlocked)
     680                 :           0 :                 LockBuffer(stack->buffer, GIST_UNLOCK);
     681                 :         179 :             xlocked = false;
     682                 :         179 :             ReleaseBuffer(stack->buffer);
     683                 :         179 :             state.stack = stack = stack->parent;
     684                 :             :         }
     685                 :             : 
     686         [ +  + ]:     1212779 :         if (!XLogRecPtrIsValid(stack->lsn))
     687                 :     1212699 :             stack->buffer = ReadBuffer(state.r, stack->blkno);
     688                 :             : 
     689                 :             :         /*
     690                 :             :          * Be optimistic and grab shared lock first. Swap it for an exclusive
     691                 :             :          * lock later if we need to update the page.
     692                 :             :          */
     693         [ +  + ]:     1212779 :         if (!xlocked)
     694                 :             :         {
     695                 :     1212778 :             LockBuffer(stack->buffer, GIST_SHARE);
     696                 :     1212778 :             gistcheckpage(state.r, stack->buffer);
     697                 :             :         }
     698                 :             : 
     699                 :     1212779 :         stack->page = BufferGetPage(stack->buffer);
     700                 :     1212779 :         stack->lsn = xlocked ?
     701         [ +  + ]:     1212779 :             PageGetLSN(stack->page) : BufferGetLSNAtomic(stack->buffer);
     702                 :             :         Assert(!RelationNeedsWAL(state.r) || XLogRecPtrIsValid(stack->lsn));
     703                 :             : 
     704                 :             :         /*
     705                 :             :          * If this page was split but the downlink was never inserted to the
     706                 :             :          * parent because the inserting backend crashed before doing that, fix
     707                 :             :          * that now.
     708                 :             :          */
     709         [ -  + ]:     1212779 :         if (GistFollowRight(stack->page))
     710                 :             :         {
     711         [ #  # ]:           0 :             if (!xlocked)
     712                 :             :             {
     713                 :           0 :                 LockBuffer(stack->buffer, GIST_UNLOCK);
     714                 :           0 :                 LockBuffer(stack->buffer, GIST_EXCLUSIVE);
     715                 :           0 :                 xlocked = true;
     716                 :             :                 /* someone might've completed the split when we unlocked */
     717         [ #  # ]:           0 :                 if (!GistFollowRight(stack->page))
     718                 :           0 :                     continue;
     719                 :             :             }
     720                 :           0 :             gistfixsplit(&state, giststate);
     721                 :             : 
     722                 :           0 :             UnlockReleaseBuffer(stack->buffer);
     723                 :           0 :             xlocked = false;
     724                 :           0 :             state.stack = stack = stack->parent;
     725                 :           0 :             continue;
     726                 :             :         }
     727                 :             : 
     728   [ +  +  +  - ]:     1892302 :         if ((stack->blkno != GIST_ROOT_BLKNO &&
     729                 :      679523 :              stack->parent->lsn < GistPageGetNSN(stack->page)) ||
     730         [ -  + ]:     1212779 :             GistPageIsDeleted(stack->page))
     731                 :             :         {
     732                 :             :             /*
     733                 :             :              * Concurrent split or page deletion detected. There's no
     734                 :             :              * guarantee that the downlink for this page is consistent with
     735                 :             :              * the tuple we're inserting anymore, so go back to parent and
     736                 :             :              * rechoose the best child.
     737                 :             :              */
     738                 :           0 :             UnlockReleaseBuffer(stack->buffer);
     739                 :           0 :             xlocked = false;
     740                 :           0 :             state.stack = stack = stack->parent;
     741                 :           0 :             continue;
     742                 :             :         }
     743                 :             : 
     744         [ +  + ]:     1212779 :         if (!GistPageIsLeaf(stack->page))
     745                 :             :         {
     746                 :             :             /*
     747                 :             :              * This is an internal page so continue to walk down the tree.
     748                 :             :              * Find the child node that has the minimum insertion penalty.
     749                 :             :              */
     750                 :             :             BlockNumber childblkno;
     751                 :             :             IndexTuple  newtup;
     752                 :             :             GISTInsertStack *item;
     753                 :             :             OffsetNumber downlinkoffnum;
     754                 :             : 
     755                 :      679590 :             downlinkoffnum = gistchoose(state.r, stack->page, itup, giststate);
     756                 :      679590 :             iid = PageGetItemId(stack->page, downlinkoffnum);
     757                 :      679590 :             idxtuple = (IndexTuple) PageGetItem(stack->page, iid);
     758                 :      679590 :             childblkno = ItemPointerGetBlockNumber(&(idxtuple->t_tid));
     759                 :             : 
     760                 :             :             /*
     761                 :             :              * Check that it's not a leftover invalid tuple from pre-9.1
     762                 :             :              */
     763         [ -  + ]:      679590 :             if (GistTupleIsInvalid(idxtuple))
     764         [ #  # ]:           0 :                 ereport(ERROR,
     765                 :             :                         (errmsg("index \"%s\" contains an inner tuple marked as invalid",
     766                 :             :                                 RelationGetRelationName(r)),
     767                 :             :                          errdetail("This is caused by an incomplete page split at crash recovery before upgrading to PostgreSQL 9.1."),
     768                 :             :                          errhint("Please REINDEX it.")));
     769                 :             : 
     770                 :             :             /*
     771                 :             :              * Check that the key representing the target child node is
     772                 :             :              * consistent with the key we're inserting. Update it if it's not.
     773                 :             :              */
     774                 :      679590 :             newtup = gistgetadjusted(state.r, idxtuple, itup, giststate);
     775         [ +  + ]:      679590 :             if (newtup)
     776                 :             :             {
     777                 :             :                 /*
     778                 :             :                  * Swap shared lock for an exclusive one. Beware, the page may
     779                 :             :                  * change while we unlock/lock the page...
     780                 :             :                  */
     781         [ +  - ]:      403225 :                 if (!xlocked)
     782                 :             :                 {
     783                 :      403225 :                     LockBuffer(stack->buffer, GIST_UNLOCK);
     784                 :      403225 :                     LockBuffer(stack->buffer, GIST_EXCLUSIVE);
     785                 :      403225 :                     xlocked = true;
     786                 :      403225 :                     stack->page = BufferGetPage(stack->buffer);
     787                 :             : 
     788         [ -  + ]:      403225 :                     if (PageGetLSN(stack->page) != stack->lsn)
     789                 :             :                     {
     790                 :             :                         /* the page was changed while we unlocked it, retry */
     791                 :           0 :                         continue;
     792                 :             :                     }
     793                 :             :                 }
     794                 :             : 
     795                 :             :                 /*
     796                 :             :                  * Update the tuple.
     797                 :             :                  *
     798                 :             :                  * We still hold the lock after gistinserttuple(), but it
     799                 :             :                  * might have to split the page to make the updated tuple fit.
     800                 :             :                  * In that case the updated tuple might migrate to the other
     801                 :             :                  * half of the split, so we have to go back to the parent and
     802                 :             :                  * descend back to the half that's a better fit for the new
     803                 :             :                  * tuple.
     804                 :             :                  */
     805         [ +  + ]:      403225 :                 if (gistinserttuple(&state, stack, giststate, newtup,
     806                 :             :                                     downlinkoffnum))
     807                 :             :                 {
     808                 :             :                     /*
     809                 :             :                      * If this was a root split, the root page continues to be
     810                 :             :                      * the parent and the updated tuple went to one of the
     811                 :             :                      * child pages, so we just need to retry from the root
     812                 :             :                      * page.
     813                 :             :                      */
     814         [ +  + ]:          80 :                     if (stack->blkno != GIST_ROOT_BLKNO)
     815                 :             :                     {
     816                 :          79 :                         UnlockReleaseBuffer(stack->buffer);
     817                 :          79 :                         xlocked = false;
     818                 :          79 :                         state.stack = stack = stack->parent;
     819                 :             :                     }
     820                 :          80 :                     continue;
     821                 :             :                 }
     822                 :             :             }
     823                 :      679510 :             LockBuffer(stack->buffer, GIST_UNLOCK);
     824                 :      679510 :             xlocked = false;
     825                 :             : 
     826                 :             :             /* descend to the chosen child */
     827                 :      679510 :             item = palloc0_object(GISTInsertStack);
     828                 :      679510 :             item->blkno = childblkno;
     829                 :      679510 :             item->parent = stack;
     830                 :      679510 :             item->downlinkoffnum = downlinkoffnum;
     831                 :      679510 :             state.stack = stack = item;
     832                 :             :         }
     833                 :             :         else
     834                 :             :         {
     835                 :             :             /*
     836                 :             :              * Leaf page. Insert the new key. We've already updated all the
     837                 :             :              * parents on the way down, but we might have to split the page if
     838                 :             :              * it doesn't fit. gistinserttuple() will take care of that.
     839                 :             :              */
     840                 :             : 
     841                 :             :             /*
     842                 :             :              * Swap shared lock for an exclusive one. Be careful, the page may
     843                 :             :              * change while we unlock/lock the page...
     844                 :             :              */
     845         [ +  - ]:      533189 :             if (!xlocked)
     846                 :             :             {
     847                 :      533189 :                 LockBuffer(stack->buffer, GIST_UNLOCK);
     848                 :      533189 :                 LockBuffer(stack->buffer, GIST_EXCLUSIVE);
     849                 :      533189 :                 xlocked = true;
     850                 :      533189 :                 stack->page = BufferGetPage(stack->buffer);
     851                 :      533189 :                 stack->lsn = PageGetLSN(stack->page);
     852                 :             : 
     853         [ +  + ]:      533189 :                 if (stack->blkno == GIST_ROOT_BLKNO)
     854                 :             :                 {
     855                 :             :                     /*
     856                 :             :                      * the only page that can become inner instead of leaf is
     857                 :             :                      * the root page, so for root we should recheck it
     858                 :             :                      */
     859         [ -  + ]:       24121 :                     if (!GistPageIsLeaf(stack->page))
     860                 :             :                     {
     861                 :             :                         /*
     862                 :             :                          * very rare situation: during unlock/lock index with
     863                 :             :                          * number of pages = 1 was increased
     864                 :             :                          */
     865                 :           0 :                         LockBuffer(stack->buffer, GIST_UNLOCK);
     866                 :           0 :                         xlocked = false;
     867                 :           0 :                         continue;
     868                 :             :                     }
     869                 :             : 
     870                 :             :                     /*
     871                 :             :                      * we don't need to check root split, because checking
     872                 :             :                      * leaf/inner is enough to recognize split for root
     873                 :             :                      */
     874                 :             :                 }
     875   [ +  -  +  - ]:     1018136 :                 else if ((GistFollowRight(stack->page) ||
     876                 :      509068 :                           stack->parent->lsn < GistPageGetNSN(stack->page)) ||
     877         [ -  + ]:      509068 :                          GistPageIsDeleted(stack->page))
     878                 :             :                 {
     879                 :             :                     /*
     880                 :             :                      * The page was split or deleted while we momentarily
     881                 :             :                      * unlocked the page. Go back to parent.
     882                 :             :                      */
     883                 :           0 :                     UnlockReleaseBuffer(stack->buffer);
     884                 :           0 :                     xlocked = false;
     885                 :           0 :                     state.stack = stack = stack->parent;
     886                 :           0 :                     continue;
     887                 :             :                 }
     888                 :             :             }
     889                 :             : 
     890                 :             :             /* now state.stack->(page, buffer and blkno) points to leaf page */
     891                 :             : 
     892                 :      533189 :             gistinserttuple(&state, stack, giststate, itup,
     893                 :             :                             InvalidOffsetNumber);
     894                 :      533183 :             LockBuffer(stack->buffer, GIST_UNLOCK);
     895                 :             : 
     896                 :             :             /* Release any pins we might still hold before exiting */
     897         [ +  + ]:     1745613 :             for (; stack; stack = stack->parent)
     898                 :     1212430 :                 ReleaseBuffer(stack->buffer);
     899                 :      533183 :             break;
     900                 :             :         }
     901                 :             :     }
     902                 :      533183 : }
     903                 :             : 
     904                 :             : /*
     905                 :             :  * Traverse the tree to find path from root page to specified "child" block.
     906                 :             :  *
     907                 :             :  * returns a new insertion stack, starting from the parent of "child", up
     908                 :             :  * to the root. *downlinkoffnum is set to the offset of the downlink in the
     909                 :             :  * direct parent of child.
     910                 :             :  *
     911                 :             :  * To prevent deadlocks, this should lock only one page at a time.
     912                 :             :  */
     913                 :             : static GISTInsertStack *
     914                 :           1 : gistFindPath(Relation r, BlockNumber child, OffsetNumber *downlinkoffnum)
     915                 :             : {
     916                 :             :     Page        page;
     917                 :             :     Buffer      buffer;
     918                 :             :     OffsetNumber i,
     919                 :             :                 maxoff;
     920                 :             :     ItemId      iid;
     921                 :             :     IndexTuple  idxtuple;
     922                 :             :     List       *fifo;
     923                 :             :     GISTInsertStack *top,
     924                 :             :                *ptr;
     925                 :             :     BlockNumber blkno;
     926                 :             : 
     927                 :           1 :     top = palloc0_object(GISTInsertStack);
     928                 :           1 :     top->blkno = GIST_ROOT_BLKNO;
     929                 :           1 :     top->downlinkoffnum = InvalidOffsetNumber;
     930                 :             : 
     931                 :           1 :     fifo = list_make1(top);
     932         [ +  - ]:           2 :     while (fifo != NIL)
     933                 :             :     {
     934                 :             :         /* Get next page to visit */
     935                 :           2 :         top = linitial(fifo);
     936                 :           2 :         fifo = list_delete_first(fifo);
     937                 :             : 
     938                 :           2 :         buffer = ReadBuffer(r, top->blkno);
     939                 :           2 :         LockBuffer(buffer, GIST_SHARE);
     940                 :           2 :         gistcheckpage(r, buffer);
     941                 :           2 :         page = BufferGetPage(buffer);
     942                 :             : 
     943         [ -  + ]:           2 :         if (GistPageIsLeaf(page))
     944                 :             :         {
     945                 :             :             /*
     946                 :             :              * Because we scan the index top-down, all the rest of the pages
     947                 :             :              * in the queue must be leaf pages as well.
     948                 :             :              */
     949                 :           0 :             UnlockReleaseBuffer(buffer);
     950                 :           0 :             break;
     951                 :             :         }
     952                 :             : 
     953                 :             :         /* currently, internal pages are never deleted */
     954                 :             :         Assert(!GistPageIsDeleted(page));
     955                 :             : 
     956                 :           2 :         top->lsn = BufferGetLSNAtomic(buffer);
     957                 :             : 
     958                 :             :         /*
     959                 :             :          * If F_FOLLOW_RIGHT is set, the page to the right doesn't have a
     960                 :             :          * downlink. This should not normally happen..
     961                 :             :          */
     962         [ -  + ]:           2 :         if (GistFollowRight(page))
     963         [ #  # ]:           0 :             elog(ERROR, "concurrent GiST page split was incomplete");
     964                 :             : 
     965   [ +  +  -  + ]:           2 :         if (top->parent && top->parent->lsn < GistPageGetNSN(page) &&
     966         [ #  # ]:           0 :             GistPageGetOpaque(page)->rightlink != InvalidBlockNumber /* sanity check */ )
     967                 :             :         {
     968                 :             :             /*
     969                 :             :              * Page was split while we looked elsewhere. We didn't see the
     970                 :             :              * downlink to the right page when we scanned the parent, so add
     971                 :             :              * it to the queue now.
     972                 :             :              *
     973                 :             :              * Put the right page ahead of the queue, so that we visit it
     974                 :             :              * next. That's important, because if this is the lowest internal
     975                 :             :              * level, just above leaves, we might already have queued up some
     976                 :             :              * leaf pages, and we assume that there can't be any non-leaf
     977                 :             :              * pages behind leaf pages.
     978                 :             :              */
     979                 :           0 :             ptr = palloc0_object(GISTInsertStack);
     980                 :           0 :             ptr->blkno = GistPageGetOpaque(page)->rightlink;
     981                 :           0 :             ptr->downlinkoffnum = InvalidOffsetNumber;
     982                 :           0 :             ptr->parent = top->parent;
     983                 :             : 
     984                 :           0 :             fifo = lcons(ptr, fifo);
     985                 :             :         }
     986                 :             : 
     987                 :           2 :         maxoff = PageGetMaxOffsetNumber(page);
     988                 :             : 
     989         [ +  + ]:          13 :         for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
     990                 :             :         {
     991                 :          12 :             iid = PageGetItemId(page, i);
     992                 :          12 :             idxtuple = (IndexTuple) PageGetItem(page, iid);
     993                 :          12 :             blkno = ItemPointerGetBlockNumber(&(idxtuple->t_tid));
     994         [ +  + ]:          12 :             if (blkno == child)
     995                 :             :             {
     996                 :             :                 /* Found it! */
     997                 :           1 :                 UnlockReleaseBuffer(buffer);
     998                 :           1 :                 *downlinkoffnum = i;
     999                 :           1 :                 return top;
    1000                 :             :             }
    1001                 :             :             else
    1002                 :             :             {
    1003                 :             :                 /* Append this child to the list of pages to visit later */
    1004                 :          11 :                 ptr = palloc0_object(GISTInsertStack);
    1005                 :          11 :                 ptr->blkno = blkno;
    1006                 :          11 :                 ptr->downlinkoffnum = i;
    1007                 :          11 :                 ptr->parent = top;
    1008                 :             : 
    1009                 :          11 :                 fifo = lappend(fifo, ptr);
    1010                 :             :             }
    1011                 :             :         }
    1012                 :             : 
    1013                 :           1 :         UnlockReleaseBuffer(buffer);
    1014                 :             :     }
    1015                 :             : 
    1016         [ #  # ]:           0 :     elog(ERROR, "failed to re-find parent of a page in index \"%s\", block %u",
    1017                 :             :          RelationGetRelationName(r), child);
    1018                 :             :     return NULL;                /* keep compiler quiet */
    1019                 :             : }
    1020                 :             : 
    1021                 :             : /*
    1022                 :             :  * Updates the stack so that child->parent is the correct parent of the
    1023                 :             :  * child. child->parent must be exclusively locked on entry, and will
    1024                 :             :  * remain so at exit, but it might not be the same page anymore.
    1025                 :             :  */
    1026                 :             : static void
    1027                 :       13623 : gistFindCorrectParent(Relation r, GISTInsertStack *child, bool is_build)
    1028                 :             : {
    1029                 :       13623 :     GISTInsertStack *parent = child->parent;
    1030                 :             :     ItemId      iid;
    1031                 :             :     IndexTuple  idxtuple;
    1032                 :             :     OffsetNumber maxoff;
    1033                 :             :     GISTInsertStack *ptr;
    1034                 :             : 
    1035                 :       13623 :     gistcheckpage(r, parent->buffer);
    1036                 :       13623 :     parent->page = BufferGetPage(parent->buffer);
    1037                 :       13623 :     maxoff = PageGetMaxOffsetNumber(parent->page);
    1038                 :             : 
    1039                 :             :     /* Check if the downlink is still where it was before */
    1040   [ +  +  -  + ]:       13623 :     if (child->downlinkoffnum != InvalidOffsetNumber && child->downlinkoffnum <= maxoff)
    1041                 :             :     {
    1042                 :       13621 :         iid = PageGetItemId(parent->page, child->downlinkoffnum);
    1043                 :       13621 :         idxtuple = (IndexTuple) PageGetItem(parent->page, iid);
    1044         [ -  + ]:       13621 :         if (ItemPointerGetBlockNumber(&(idxtuple->t_tid)) == child->blkno)
    1045                 :       13621 :             return;             /* still there */
    1046                 :             :     }
    1047                 :             : 
    1048                 :             :     /*
    1049                 :             :      * The page has changed since we looked. During normal operation, every
    1050                 :             :      * update of a page changes its LSN, so the LSN we memorized should have
    1051                 :             :      * changed too.
    1052                 :             :      *
    1053                 :             :      * During index build, however, we don't WAL-log the changes until we have
    1054                 :             :      * built the index, so the LSN doesn't change. There is no concurrent
    1055                 :             :      * activity during index build, but we might have changed the parent
    1056                 :             :      * ourselves.
    1057                 :             :      *
    1058                 :             :      * We will also get here if child->downlinkoffnum is invalid. That happens
    1059                 :             :      * if 'parent' had been updated by an earlier call to this function on its
    1060                 :             :      * grandchild, which had to move right.
    1061                 :             :      */
    1062                 :             :     Assert(parent->lsn != PageGetLSN(parent->page) || is_build ||
    1063                 :             :            child->downlinkoffnum == InvalidOffsetNumber);
    1064                 :             : 
    1065                 :             :     /*
    1066                 :             :      * Scan the page to re-find the downlink. If the page was split, it might
    1067                 :             :      * have moved to a different page, so follow the right links until we find
    1068                 :             :      * it.
    1069                 :             :      */
    1070                 :             :     while (true)
    1071                 :           1 :     {
    1072                 :             :         OffsetNumber i;
    1073                 :             : 
    1074                 :           3 :         maxoff = PageGetMaxOffsetNumber(parent->page);
    1075         [ +  + ]:          12 :         for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
    1076                 :             :         {
    1077                 :          10 :             iid = PageGetItemId(parent->page, i);
    1078                 :          10 :             idxtuple = (IndexTuple) PageGetItem(parent->page, iid);
    1079         [ +  + ]:          10 :             if (ItemPointerGetBlockNumber(&(idxtuple->t_tid)) == child->blkno)
    1080                 :             :             {
    1081                 :             :                 /* yes!!, found */
    1082                 :           1 :                 child->downlinkoffnum = i;
    1083                 :           1 :                 return;
    1084                 :             :             }
    1085                 :             :         }
    1086                 :             : 
    1087                 :           2 :         parent->blkno = GistPageGetOpaque(parent->page)->rightlink;
    1088                 :           2 :         parent->downlinkoffnum = InvalidOffsetNumber;
    1089                 :           2 :         UnlockReleaseBuffer(parent->buffer);
    1090         [ +  + ]:           2 :         if (parent->blkno == InvalidBlockNumber)
    1091                 :             :         {
    1092                 :             :             /*
    1093                 :             :              * End of chain and still didn't find parent. It's a very-very
    1094                 :             :              * rare situation when the root was split.
    1095                 :             :              */
    1096                 :           1 :             break;
    1097                 :             :         }
    1098                 :           1 :         parent->buffer = ReadBuffer(r, parent->blkno);
    1099                 :           1 :         LockBuffer(parent->buffer, GIST_EXCLUSIVE);
    1100                 :           1 :         gistcheckpage(r, parent->buffer);
    1101                 :           1 :         parent->page = BufferGetPage(parent->buffer);
    1102                 :             :     }
    1103                 :             : 
    1104                 :             :     /*
    1105                 :             :      * awful!!, we need search tree to find parent ... , but before we should
    1106                 :             :      * release all old parent
    1107                 :             :      */
    1108                 :             : 
    1109                 :           1 :     ptr = child->parent->parent;  /* child->parent already released above */
    1110         [ -  + ]:           1 :     while (ptr)
    1111                 :             :     {
    1112                 :           0 :         ReleaseBuffer(ptr->buffer);
    1113                 :           0 :         ptr = ptr->parent;
    1114                 :             :     }
    1115                 :             : 
    1116                 :             :     /* ok, find new path */
    1117                 :           1 :     ptr = parent = gistFindPath(r, child->blkno, &child->downlinkoffnum);
    1118                 :             : 
    1119                 :             :     /* read all buffers as expected by caller */
    1120                 :             :     /* note we don't lock them or gistcheckpage them here! */
    1121         [ +  + ]:           3 :     while (ptr)
    1122                 :             :     {
    1123                 :           2 :         ptr->buffer = ReadBuffer(r, ptr->blkno);
    1124                 :           2 :         ptr->page = BufferGetPage(ptr->buffer);
    1125                 :           2 :         ptr = ptr->parent;
    1126                 :             :     }
    1127                 :             : 
    1128                 :             :     /* install new chain of parents to stack */
    1129                 :           1 :     child->parent = parent;
    1130                 :             : 
    1131                 :             :     /* make recursive call to normal processing */
    1132                 :           1 :     LockBuffer(child->parent->buffer, GIST_EXCLUSIVE);
    1133                 :           1 :     gistFindCorrectParent(r, child, is_build);
    1134                 :             : }
    1135                 :             : 
    1136                 :             : /*
    1137                 :             :  * Form a downlink pointer for the page in 'buf'.
    1138                 :             :  */
    1139                 :             : static IndexTuple
    1140                 :           0 : gistformdownlink(Relation rel, Buffer buf, GISTSTATE *giststate,
    1141                 :             :                  GISTInsertStack *stack, bool is_build)
    1142                 :             : {
    1143                 :           0 :     Page        page = BufferGetPage(buf);
    1144                 :             :     OffsetNumber maxoff;
    1145                 :             :     OffsetNumber offset;
    1146                 :           0 :     IndexTuple  downlink = NULL;
    1147                 :             : 
    1148                 :           0 :     maxoff = PageGetMaxOffsetNumber(page);
    1149         [ #  # ]:           0 :     for (offset = FirstOffsetNumber; offset <= maxoff; offset = OffsetNumberNext(offset))
    1150                 :             :     {
    1151                 :             :         IndexTuple  ituple = (IndexTuple)
    1152                 :           0 :             PageGetItem(page, PageGetItemId(page, offset));
    1153                 :             : 
    1154         [ #  # ]:           0 :         if (downlink == NULL)
    1155                 :           0 :             downlink = CopyIndexTuple(ituple);
    1156                 :             :         else
    1157                 :             :         {
    1158                 :             :             IndexTuple  newdownlink;
    1159                 :             : 
    1160                 :           0 :             newdownlink = gistgetadjusted(rel, downlink, ituple,
    1161                 :             :                                           giststate);
    1162         [ #  # ]:           0 :             if (newdownlink)
    1163                 :           0 :                 downlink = newdownlink;
    1164                 :             :         }
    1165                 :             :     }
    1166                 :             : 
    1167                 :             :     /*
    1168                 :             :      * If the page is completely empty, we can't form a meaningful downlink
    1169                 :             :      * for it. But we have to insert a downlink for the page. Any key will do,
    1170                 :             :      * as long as its consistent with the downlink of parent page, so that we
    1171                 :             :      * can legally insert it to the parent. A minimal one that matches as few
    1172                 :             :      * scans as possible would be best, to keep scans from doing useless work,
    1173                 :             :      * but we don't know how to construct that. So we just use the downlink of
    1174                 :             :      * the original page that was split - that's as far from optimal as it can
    1175                 :             :      * get but will do..
    1176                 :             :      */
    1177         [ #  # ]:           0 :     if (!downlink)
    1178                 :             :     {
    1179                 :             :         ItemId      iid;
    1180                 :             : 
    1181                 :           0 :         LockBuffer(stack->parent->buffer, GIST_EXCLUSIVE);
    1182                 :           0 :         gistFindCorrectParent(rel, stack, is_build);
    1183                 :           0 :         iid = PageGetItemId(stack->parent->page, stack->downlinkoffnum);
    1184                 :           0 :         downlink = (IndexTuple) PageGetItem(stack->parent->page, iid);
    1185                 :           0 :         downlink = CopyIndexTuple(downlink);
    1186                 :           0 :         LockBuffer(stack->parent->buffer, GIST_UNLOCK);
    1187                 :             :     }
    1188                 :             : 
    1189                 :           0 :     ItemPointerSetBlockNumber(&(downlink->t_tid), BufferGetBlockNumber(buf));
    1190                 :           0 :     GistTupleSetValid(downlink);
    1191                 :             : 
    1192                 :           0 :     return downlink;
    1193                 :             : }
    1194                 :             : 
    1195                 :             : 
    1196                 :             : /*
    1197                 :             :  * Complete the incomplete split of state->stack->page.
    1198                 :             :  */
    1199                 :             : static void
    1200                 :           0 : gistfixsplit(GISTInsertState *state, GISTSTATE *giststate)
    1201                 :             : {
    1202                 :           0 :     GISTInsertStack *stack = state->stack;
    1203                 :             :     Buffer      buf;
    1204                 :             :     Page        page;
    1205                 :           0 :     List       *splitinfo = NIL;
    1206                 :             : 
    1207         [ #  # ]:           0 :     ereport(LOG,
    1208                 :             :             (errmsg("fixing incomplete split in index \"%s\", block %u",
    1209                 :             :                     RelationGetRelationName(state->r), stack->blkno)));
    1210                 :             : 
    1211                 :             :     Assert(GistFollowRight(stack->page));
    1212                 :             :     Assert(OffsetNumberIsValid(stack->downlinkoffnum));
    1213                 :             : 
    1214                 :           0 :     buf = stack->buffer;
    1215                 :             : 
    1216                 :             :     /*
    1217                 :             :      * Read the chain of split pages, following the rightlinks. Construct a
    1218                 :             :      * downlink tuple for each page.
    1219                 :             :      */
    1220                 :             :     for (;;)
    1221                 :           0 :     {
    1222                 :           0 :         GISTPageSplitInfo *si = palloc_object(GISTPageSplitInfo);
    1223                 :             :         IndexTuple  downlink;
    1224                 :             : 
    1225                 :           0 :         page = BufferGetPage(buf);
    1226                 :             : 
    1227                 :             :         /* Form the new downlink tuples to insert to parent */
    1228                 :           0 :         downlink = gistformdownlink(state->r, buf, giststate, stack, state->is_build);
    1229                 :             : 
    1230                 :           0 :         si->buf = buf;
    1231                 :           0 :         si->downlink = downlink;
    1232                 :             : 
    1233                 :           0 :         splitinfo = lappend(splitinfo, si);
    1234                 :             : 
    1235         [ #  # ]:           0 :         if (GistFollowRight(page))
    1236                 :             :         {
    1237                 :             :             /* lock next page */
    1238                 :           0 :             buf = ReadBuffer(state->r, GistPageGetOpaque(page)->rightlink);
    1239                 :           0 :             LockBuffer(buf, GIST_EXCLUSIVE);
    1240                 :             :         }
    1241                 :             :         else
    1242                 :           0 :             break;
    1243                 :             :     }
    1244                 :             : 
    1245                 :             :     /* Insert the downlinks */
    1246                 :           0 :     gistfinishsplit(state, stack, giststate, splitinfo, false);
    1247                 :           0 : }
    1248                 :             : 
    1249                 :             : /*
    1250                 :             :  * Insert or replace a tuple in stack->buffer. If 'oldoffnum' is valid, the
    1251                 :             :  * tuple at 'oldoffnum' is replaced, otherwise the tuple is inserted as new.
    1252                 :             :  * 'stack' represents the path from the root to the page being updated.
    1253                 :             :  *
    1254                 :             :  * The caller must hold an exclusive lock on stack->buffer.  The lock is still
    1255                 :             :  * held on return, but the page might not contain the inserted tuple if the
    1256                 :             :  * page was split. The function returns true if the page was split, false
    1257                 :             :  * otherwise.
    1258                 :             :  */
    1259                 :             : static bool
    1260                 :      936414 : gistinserttuple(GISTInsertState *state, GISTInsertStack *stack,
    1261                 :             :                 GISTSTATE *giststate, IndexTuple tuple, OffsetNumber oldoffnum)
    1262                 :             : {
    1263                 :      936414 :     return gistinserttuples(state, stack, giststate, &tuple, 1, oldoffnum,
    1264                 :             :                             InvalidBuffer, InvalidBuffer, false, false);
    1265                 :             : }
    1266                 :             : 
    1267                 :             : /* ----------------
    1268                 :             :  * An extended workhorse version of gistinserttuple(). This version allows
    1269                 :             :  * inserting multiple tuples, or replacing a single tuple with multiple tuples.
    1270                 :             :  * This is used to recursively update the downlinks in the parent when a page
    1271                 :             :  * is split.
    1272                 :             :  *
    1273                 :             :  * If leftchild and rightchild are valid, we're inserting/replacing the
    1274                 :             :  * downlink for rightchild, and leftchild is its left sibling. We clear the
    1275                 :             :  * F_FOLLOW_RIGHT flag and update NSN on leftchild, atomically with the
    1276                 :             :  * insertion of the downlink.
    1277                 :             :  *
    1278                 :             :  * To avoid holding locks for longer than necessary, when recursing up the
    1279                 :             :  * tree to update the parents, the locking is a bit peculiar here. On entry,
    1280                 :             :  * the caller must hold an exclusive lock on stack->buffer, as well as
    1281                 :             :  * leftchild and rightchild if given. On return:
    1282                 :             :  *
    1283                 :             :  *  - Lock on stack->buffer is released, if 'unlockbuf' is true. The page is
    1284                 :             :  *    always kept pinned, however.
    1285                 :             :  *  - Lock on 'leftchild' is released, if 'unlockleftchild' is true. The page
    1286                 :             :  *    is kept pinned.
    1287                 :             :  *  - Lock and pin on 'rightchild' are always released.
    1288                 :             :  *
    1289                 :             :  * Returns 'true' if the page had to be split. Note that if the page was
    1290                 :             :  * split, the inserted/updated tuples might've been inserted to a right
    1291                 :             :  * sibling of stack->buffer instead of stack->buffer itself.
    1292                 :             :  */
    1293                 :             : static bool
    1294                 :      950036 : gistinserttuples(GISTInsertState *state, GISTInsertStack *stack,
    1295                 :             :                  GISTSTATE *giststate,
    1296                 :             :                  IndexTuple *tuples, int ntup, OffsetNumber oldoffnum,
    1297                 :             :                  Buffer leftchild, Buffer rightchild,
    1298                 :             :                  bool unlockbuf, bool unlockleftchild)
    1299                 :             : {
    1300                 :             :     List       *splitinfo;
    1301                 :             :     bool        is_split;
    1302                 :             : 
    1303                 :             :     /*
    1304                 :             :      * Check for any rw conflicts (in serializable isolation level) just
    1305                 :             :      * before we intend to modify the page
    1306                 :             :      */
    1307                 :      950036 :     CheckForSerializableConflictIn(state->r, NULL, BufferGetBlockNumber(stack->buffer));
    1308                 :             : 
    1309                 :             :     /* Insert the tuple(s) to the page, splitting the page if necessary */
    1310                 :      950030 :     is_split = gistplacetopage(state->r, state->freespace, giststate,
    1311                 :             :                                stack->buffer,
    1312                 :             :                                tuples, ntup,
    1313                 :             :                                oldoffnum, NULL,
    1314                 :             :                                leftchild,
    1315                 :             :                                &splitinfo,
    1316                 :             :                                true,
    1317                 :             :                                state->heapRel,
    1318                 :      950030 :                                state->is_build);
    1319                 :             : 
    1320                 :             :     /*
    1321                 :             :      * Before recursing up in case the page was split, release locks on the
    1322                 :             :      * child pages. We don't need to keep them locked when updating the
    1323                 :             :      * parent.
    1324                 :             :      */
    1325         [ +  + ]:      950030 :     if (BufferIsValid(rightchild))
    1326                 :       13622 :         UnlockReleaseBuffer(rightchild);
    1327   [ +  +  +  + ]:      950030 :     if (BufferIsValid(leftchild) && unlockleftchild)
    1328                 :        2613 :         LockBuffer(leftchild, GIST_UNLOCK);
    1329                 :             : 
    1330                 :             :     /*
    1331                 :             :      * If we had to split, insert/update the downlinks in the parent. If the
    1332                 :             :      * caller requested us to release the lock on stack->buffer, tell
    1333                 :             :      * gistfinishsplit() to do that as soon as it's safe to do so. If we
    1334                 :             :      * didn't have to split, release it ourselves.
    1335                 :             :      */
    1336         [ +  + ]:      950030 :     if (splitinfo)
    1337                 :       13568 :         gistfinishsplit(state, stack, giststate, splitinfo, unlockbuf);
    1338         [ +  + ]:      936462 :     else if (unlockbuf)
    1339                 :       10955 :         LockBuffer(stack->buffer, GIST_UNLOCK);
    1340                 :             : 
    1341                 :      950030 :     return is_split;
    1342                 :             : }
    1343                 :             : 
    1344                 :             : /*
    1345                 :             :  * Finish an incomplete split by inserting/updating the downlinks in parent
    1346                 :             :  * page. 'splitinfo' contains all the child pages involved in the split,
    1347                 :             :  * from left-to-right.
    1348                 :             :  *
    1349                 :             :  * On entry, the caller must hold a lock on stack->buffer and all the child
    1350                 :             :  * pages in 'splitinfo'. If 'unlockbuf' is true, the lock on stack->buffer is
    1351                 :             :  * released on return. The child pages are always unlocked and unpinned.
    1352                 :             :  */
    1353                 :             : static void
    1354                 :       13568 : gistfinishsplit(GISTInsertState *state, GISTInsertStack *stack,
    1355                 :             :                 GISTSTATE *giststate, List *splitinfo, bool unlockbuf)
    1356                 :             : {
    1357                 :             :     GISTPageSplitInfo *right;
    1358                 :             :     GISTPageSplitInfo *left;
    1359                 :             :     IndexTuple  tuples[2];
    1360                 :             : 
    1361                 :             :     /* A split always contains at least two halves */
    1362                 :             :     Assert(list_length(splitinfo) >= 2);
    1363                 :             : 
    1364                 :             :     /*
    1365                 :             :      * We need to insert downlinks for each new page, and update the downlink
    1366                 :             :      * for the original (leftmost) page in the split. Begin at the rightmost
    1367                 :             :      * page, inserting one downlink at a time until there's only two pages
    1368                 :             :      * left. Finally insert the downlink for the last new page and update the
    1369                 :             :      * downlink for the original page as one operation.
    1370                 :             :      */
    1371                 :       13568 :     LockBuffer(stack->parent->buffer, GIST_EXCLUSIVE);
    1372                 :             : 
    1373                 :             :     /*
    1374                 :             :      * Insert downlinks for the siblings from right to left, until there are
    1375                 :             :      * only two siblings left.
    1376                 :             :      */
    1377         [ +  + ]:       13622 :     for (int pos = list_length(splitinfo) - 1; pos > 1; pos--)
    1378                 :             :     {
    1379                 :          54 :         right = (GISTPageSplitInfo *) list_nth(splitinfo, pos);
    1380                 :          54 :         left = (GISTPageSplitInfo *) list_nth(splitinfo, pos - 1);
    1381                 :             : 
    1382                 :          54 :         gistFindCorrectParent(state->r, stack, state->is_build);
    1383         [ +  + ]:          54 :         if (gistinserttuples(state, stack->parent, giststate,
    1384                 :             :                              &right->downlink, 1,
    1385                 :             :                              InvalidOffsetNumber,
    1386                 :             :                              left->buf, right->buf, false, false))
    1387                 :             :         {
    1388                 :             :             /*
    1389                 :             :              * If the parent page was split, the existing downlink might have
    1390                 :             :              * moved.
    1391                 :             :              */
    1392                 :           1 :             stack->downlinkoffnum = InvalidOffsetNumber;
    1393                 :             :         }
    1394                 :             :         /* gistinserttuples() released the lock on right->buf. */
    1395                 :             :     }
    1396                 :             : 
    1397                 :       13568 :     right = (GISTPageSplitInfo *) lsecond(splitinfo);
    1398                 :       13568 :     left = (GISTPageSplitInfo *) linitial(splitinfo);
    1399                 :             : 
    1400                 :             :     /*
    1401                 :             :      * Finally insert downlink for the remaining right page and update the
    1402                 :             :      * downlink for the original page to not contain the tuples that were
    1403                 :             :      * moved to the new pages.
    1404                 :             :      */
    1405                 :       13568 :     tuples[0] = left->downlink;
    1406                 :       13568 :     tuples[1] = right->downlink;
    1407                 :       13568 :     gistFindCorrectParent(state->r, stack, state->is_build);
    1408                 :       13568 :     (void) gistinserttuples(state, stack->parent, giststate,
    1409                 :             :                             tuples, 2,
    1410                 :       13568 :                             stack->downlinkoffnum,
    1411                 :             :                             left->buf, right->buf,
    1412                 :             :                             true,   /* Unlock parent */
    1413                 :             :                             unlockbuf   /* Unlock stack->buffer if caller
    1414                 :             :                                          * wants that */
    1415                 :             :         );
    1416                 :             : 
    1417                 :             :     /*
    1418                 :             :      * The downlink might have moved when we updated it. Even if the page
    1419                 :             :      * wasn't split, because gistinserttuples() implements updating the old
    1420                 :             :      * tuple by removing and re-inserting it!
    1421                 :             :      */
    1422                 :       13568 :     stack->downlinkoffnum = InvalidOffsetNumber;
    1423                 :             : 
    1424                 :             :     Assert(left->buf == stack->buffer);
    1425                 :             : 
    1426                 :             :     /*
    1427                 :             :      * If we split the page because we had to adjust the downlink on an
    1428                 :             :      * internal page, while descending the tree for inserting a new tuple,
    1429                 :             :      * then this might no longer be the correct page for the new tuple. The
    1430                 :             :      * downlink to this page might not cover the new tuple anymore, it might
    1431                 :             :      * need to go to the newly-created right sibling instead. Tell the caller
    1432                 :             :      * to walk back up the stack, to re-check at the parent which page to
    1433                 :             :      * insert to.
    1434                 :             :      *
    1435                 :             :      * Normally, the LSN-NSN interlock during the tree descend would also
    1436                 :             :      * detect that a concurrent split happened (by ourselves), and cause us to
    1437                 :             :      * retry at the parent. But that mechanism doesn't work during index
    1438                 :             :      * build, because we don't do WAL-logging, and don't update LSNs, during
    1439                 :             :      * index build.
    1440                 :             :      */
    1441                 :       13568 :     stack->retry_from_parent = true;
    1442                 :       13568 : }
    1443                 :             : 
    1444                 :             : /*
    1445                 :             :  * gistSplit -- split a page in the tree and fill struct
    1446                 :             :  * used for XLOG and real writes buffers. Function is recursive, ie
    1447                 :             :  * it will split page until keys will fit in every page.
    1448                 :             :  */
    1449                 :             : SplitPageLayout *
    1450                 :       15274 : gistSplit(Relation r,
    1451                 :             :           Page page,
    1452                 :             :           IndexTuple *itup,     /* contains compressed entry */
    1453                 :             :           int len,
    1454                 :             :           GISTSTATE *giststate)
    1455                 :             : {
    1456                 :             :     IndexTuple *lvectup,
    1457                 :             :                *rvectup;
    1458                 :             :     GistSplitVector v;
    1459                 :             :     int         i;
    1460                 :       15274 :     SplitPageLayout *res = NULL;
    1461                 :             : 
    1462                 :             :     /* this should never recurse very deeply, but better safe than sorry */
    1463                 :       15274 :     check_stack_depth();
    1464                 :             : 
    1465                 :             :     /* there's no point in splitting an empty page */
    1466                 :             :     Assert(len > 0);
    1467                 :             : 
    1468                 :             :     /*
    1469                 :             :      * If a single tuple doesn't fit on a page, no amount of splitting will
    1470                 :             :      * help.
    1471                 :             :      */
    1472         [ -  + ]:       15274 :     if (len == 1)
    1473         [ #  # ]:           0 :         ereport(ERROR,
    1474                 :             :                 (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
    1475                 :             :                  errmsg("index row size %zu exceeds maximum %zu for index \"%s\"",
    1476                 :             :                         IndexTupleSize(itup[0]), GiSTPageSize,
    1477                 :             :                         RelationGetRelationName(r))));
    1478                 :             : 
    1479                 :       15274 :     memset(v.spl_lisnull, true,
    1480                 :       15274 :            sizeof(bool) * giststate->nonLeafTupdesc->natts);
    1481                 :       15274 :     memset(v.spl_risnull, true,
    1482                 :       15274 :            sizeof(bool) * giststate->nonLeafTupdesc->natts);
    1483                 :       15274 :     gistSplitByKey(r, page, itup, len, giststate, &v, 0);
    1484                 :             : 
    1485                 :             :     /* form left and right vector */
    1486                 :       15274 :     lvectup = palloc_array(IndexTuple, len + 1);
    1487                 :       15274 :     rvectup = palloc_array(IndexTuple, len + 1);
    1488                 :             : 
    1489         [ +  + ]:      720257 :     for (i = 0; i < v.splitVector.spl_nleft; i++)
    1490                 :      704983 :         lvectup[i] = itup[v.splitVector.spl_left[i] - 1];
    1491                 :             : 
    1492         [ +  + ]:      811432 :     for (i = 0; i < v.splitVector.spl_nright; i++)
    1493                 :      796158 :         rvectup[i] = itup[v.splitVector.spl_right[i] - 1];
    1494                 :             : 
    1495                 :             :     /* finalize splitting (may need another split) */
    1496         [ +  + ]:       15274 :     if (!gistfitpage(rvectup, v.splitVector.spl_nright))
    1497                 :             :     {
    1498                 :         453 :         res = gistSplit(r, page, rvectup, v.splitVector.spl_nright, giststate);
    1499                 :             :     }
    1500                 :             :     else
    1501                 :             :     {
    1502                 :       14821 :         ROTATEDIST(res);
    1503                 :       14821 :         res->block.num = v.splitVector.spl_nright;
    1504                 :       14821 :         res->list = gistfillitupvec(rvectup, v.splitVector.spl_nright, &(res->lenlist));
    1505                 :       14821 :         res->itup = gistFormTuple(giststate, r, v.spl_rattr, v.spl_risnull, false);
    1506                 :             :     }
    1507                 :             : 
    1508         [ +  + ]:       15274 :     if (!gistfitpage(lvectup, v.splitVector.spl_nleft))
    1509                 :             :     {
    1510                 :             :         SplitPageLayout *resptr,
    1511                 :             :                    *subres;
    1512                 :             : 
    1513                 :         304 :         resptr = subres = gistSplit(r, page, lvectup, v.splitVector.spl_nleft, giststate);
    1514                 :             : 
    1515                 :             :         /* install on list's tail */
    1516         [ +  + ]:         761 :         while (resptr->next)
    1517                 :         457 :             resptr = resptr->next;
    1518                 :             : 
    1519                 :         304 :         resptr->next = res;
    1520                 :         304 :         res = subres;
    1521                 :             :     }
    1522                 :             :     else
    1523                 :             :     {
    1524                 :       14970 :         ROTATEDIST(res);
    1525                 :       14970 :         res->block.num = v.splitVector.spl_nleft;
    1526                 :       14970 :         res->list = gistfillitupvec(lvectup, v.splitVector.spl_nleft, &(res->lenlist));
    1527                 :       14970 :         res->itup = gistFormTuple(giststate, r, v.spl_lattr, v.spl_lisnull, false);
    1528                 :             :     }
    1529                 :             : 
    1530                 :       15274 :     return res;
    1531                 :             : }
    1532                 :             : 
    1533                 :             : /*
    1534                 :             :  * Create a GISTSTATE and fill it with information about the index
    1535                 :             :  */
    1536                 :             : GISTSTATE *
    1537                 :        9392 : initGISTstate(Relation index)
    1538                 :             : {
    1539                 :             :     GISTSTATE  *giststate;
    1540                 :             :     MemoryContext scanCxt;
    1541                 :             :     MemoryContext oldCxt;
    1542                 :             :     int         i;
    1543                 :             : 
    1544                 :             :     /* safety check to protect fixed-size arrays in GISTSTATE */
    1545         [ -  + ]:        9392 :     if (index->rd_att->natts > INDEX_MAX_KEYS)
    1546         [ #  # ]:           0 :         elog(ERROR, "numberOfAttributes %d > %d",
    1547                 :             :              index->rd_att->natts, INDEX_MAX_KEYS);
    1548                 :             : 
    1549                 :             :     /* Create the memory context that will hold the GISTSTATE */
    1550                 :        9392 :     scanCxt = AllocSetContextCreate(CurrentMemoryContext,
    1551                 :             :                                     "GiST scan context",
    1552                 :             :                                     ALLOCSET_DEFAULT_SIZES);
    1553                 :        9392 :     oldCxt = MemoryContextSwitchTo(scanCxt);
    1554                 :             : 
    1555                 :             :     /* Create and fill in the GISTSTATE */
    1556                 :        9392 :     giststate = palloc_object(GISTSTATE);
    1557                 :             : 
    1558                 :        9392 :     giststate->scanCxt = scanCxt;
    1559                 :        9392 :     giststate->tempCxt = scanCxt;    /* caller must change this if needed */
    1560                 :        9392 :     giststate->leafTupdesc = index->rd_att;
    1561                 :             : 
    1562                 :             :     /*
    1563                 :             :      * The truncated tupdesc for non-leaf index tuples, which doesn't contain
    1564                 :             :      * the INCLUDE attributes.
    1565                 :             :      *
    1566                 :             :      * It is used to form tuples during tuple adjustment and page split.
    1567                 :             :      * B-tree creates shortened tuple descriptor for every truncated tuple,
    1568                 :             :      * because it is doing this less often: it does not have to form truncated
    1569                 :             :      * tuples during page split.  Also, B-tree is not adjusting tuples on
    1570                 :             :      * internal pages the way GiST does.
    1571                 :             :      */
    1572                 :       18784 :     giststate->nonLeafTupdesc = CreateTupleDescTruncatedCopy(index->rd_att,
    1573                 :        9392 :                                                              IndexRelationGetNumberOfKeyAttributes(index));
    1574                 :             : 
    1575         [ +  + ]:       26217 :     for (i = 0; i < IndexRelationGetNumberOfKeyAttributes(index); i++)
    1576                 :             :     {
    1577                 :       16825 :         fmgr_info_copy(&(giststate->consistentFn[i]),
    1578                 :       16825 :                        index_getprocinfo(index, i + 1, GIST_CONSISTENT_PROC),
    1579                 :             :                        scanCxt);
    1580                 :       16825 :         fmgr_info_copy(&(giststate->unionFn[i]),
    1581                 :       16825 :                        index_getprocinfo(index, i + 1, GIST_UNION_PROC),
    1582                 :             :                        scanCxt);
    1583                 :             : 
    1584                 :             :         /* opclasses are not required to provide a Compress method */
    1585         [ +  + ]:       16825 :         if (OidIsValid(index_getprocid(index, i + 1, GIST_COMPRESS_PROC)))
    1586                 :        3617 :             fmgr_info_copy(&(giststate->compressFn[i]),
    1587                 :        3617 :                            index_getprocinfo(index, i + 1, GIST_COMPRESS_PROC),
    1588                 :             :                            scanCxt);
    1589                 :             :         else
    1590                 :       13208 :             giststate->compressFn[i].fn_oid = InvalidOid;
    1591                 :             : 
    1592                 :             :         /* opclasses are not required to provide a Decompress method */
    1593         [ +  + ]:       16825 :         if (OidIsValid(index_getprocid(index, i + 1, GIST_DECOMPRESS_PROC)))
    1594                 :         938 :             fmgr_info_copy(&(giststate->decompressFn[i]),
    1595                 :         938 :                            index_getprocinfo(index, i + 1, GIST_DECOMPRESS_PROC),
    1596                 :             :                            scanCxt);
    1597                 :             :         else
    1598                 :       15887 :             giststate->decompressFn[i].fn_oid = InvalidOid;
    1599                 :             : 
    1600                 :       16825 :         fmgr_info_copy(&(giststate->penaltyFn[i]),
    1601                 :       16825 :                        index_getprocinfo(index, i + 1, GIST_PENALTY_PROC),
    1602                 :             :                        scanCxt);
    1603                 :       16825 :         fmgr_info_copy(&(giststate->picksplitFn[i]),
    1604                 :       16825 :                        index_getprocinfo(index, i + 1, GIST_PICKSPLIT_PROC),
    1605                 :             :                        scanCxt);
    1606                 :       16825 :         fmgr_info_copy(&(giststate->equalFn[i]),
    1607                 :       16825 :                        index_getprocinfo(index, i + 1, GIST_EQUAL_PROC),
    1608                 :             :                        scanCxt);
    1609                 :             : 
    1610                 :             :         /* opclasses are not required to provide a Distance method */
    1611         [ +  + ]:       16825 :         if (OidIsValid(index_getprocid(index, i + 1, GIST_DISTANCE_PROC)))
    1612                 :        1123 :             fmgr_info_copy(&(giststate->distanceFn[i]),
    1613                 :        1123 :                            index_getprocinfo(index, i + 1, GIST_DISTANCE_PROC),
    1614                 :             :                            scanCxt);
    1615                 :             :         else
    1616                 :       15702 :             giststate->distanceFn[i].fn_oid = InvalidOid;
    1617                 :             : 
    1618                 :             :         /* opclasses are not required to provide a Fetch method */
    1619         [ +  + ]:       16825 :         if (OidIsValid(index_getprocid(index, i + 1, GIST_FETCH_PROC)))
    1620                 :         767 :             fmgr_info_copy(&(giststate->fetchFn[i]),
    1621                 :         767 :                            index_getprocinfo(index, i + 1, GIST_FETCH_PROC),
    1622                 :             :                            scanCxt);
    1623                 :             :         else
    1624                 :       16058 :             giststate->fetchFn[i].fn_oid = InvalidOid;
    1625                 :             : 
    1626                 :             :         /*
    1627                 :             :          * If the index column has a specified collation, we should honor that
    1628                 :             :          * while doing comparisons.  However, we may have a collatable storage
    1629                 :             :          * type for a noncollatable indexed data type.  If there's no index
    1630                 :             :          * collation then specify default collation in case the support
    1631                 :             :          * functions need collation.  This is harmless if the support
    1632                 :             :          * functions don't care about collation, so we just do it
    1633                 :             :          * unconditionally.  (We could alternatively call get_typcollation,
    1634                 :             :          * but that seems like expensive overkill --- there aren't going to be
    1635                 :             :          * any cases where a GiST storage type has a nondefault collation.)
    1636                 :             :          */
    1637         [ +  + ]:       16825 :         if (OidIsValid(index->rd_indcollation[i]))
    1638                 :          98 :             giststate->supportCollation[i] = index->rd_indcollation[i];
    1639                 :             :         else
    1640                 :       16727 :             giststate->supportCollation[i] = DEFAULT_COLLATION_OID;
    1641                 :             :     }
    1642                 :             : 
    1643                 :             :     /* No opclass information for INCLUDE attributes */
    1644         [ +  + ]:        9726 :     for (; i < index->rd_att->natts; i++)
    1645                 :             :     {
    1646                 :         334 :         giststate->consistentFn[i].fn_oid = InvalidOid;
    1647                 :         334 :         giststate->unionFn[i].fn_oid = InvalidOid;
    1648                 :         334 :         giststate->compressFn[i].fn_oid = InvalidOid;
    1649                 :         334 :         giststate->decompressFn[i].fn_oid = InvalidOid;
    1650                 :         334 :         giststate->penaltyFn[i].fn_oid = InvalidOid;
    1651                 :         334 :         giststate->picksplitFn[i].fn_oid = InvalidOid;
    1652                 :         334 :         giststate->equalFn[i].fn_oid = InvalidOid;
    1653                 :         334 :         giststate->distanceFn[i].fn_oid = InvalidOid;
    1654                 :         334 :         giststate->fetchFn[i].fn_oid = InvalidOid;
    1655                 :         334 :         giststate->supportCollation[i] = InvalidOid;
    1656                 :             :     }
    1657                 :             : 
    1658                 :        9392 :     MemoryContextSwitchTo(oldCxt);
    1659                 :             : 
    1660                 :        9392 :     return giststate;
    1661                 :             : }
    1662                 :             : 
    1663                 :             : void
    1664                 :        7206 : freeGISTstate(GISTSTATE *giststate)
    1665                 :             : {
    1666                 :             :     /* It's sufficient to delete the scanCxt */
    1667                 :        7206 :     MemoryContextDelete(giststate->scanCxt);
    1668                 :        7206 : }
    1669                 :             : 
    1670                 :             : /*
    1671                 :             :  * gistprunepage() -- try to remove LP_DEAD items from the given page.
    1672                 :             :  * Function assumes that buffer is exclusively locked.
    1673                 :             :  */
    1674                 :             : static void
    1675                 :           0 : gistprunepage(Relation rel, Page page, Buffer buffer, Relation heapRel)
    1676                 :             : {
    1677                 :             :     OffsetNumber deletable[MaxIndexTuplesPerPage];
    1678                 :           0 :     int         ndeletable = 0;
    1679                 :             :     OffsetNumber offnum,
    1680                 :             :                 maxoff;
    1681                 :             : 
    1682                 :             :     Assert(GistPageIsLeaf(page));
    1683                 :             : 
    1684                 :             :     /*
    1685                 :             :      * Scan over all items to see which ones need to be deleted according to
    1686                 :             :      * LP_DEAD flags.
    1687                 :             :      */
    1688                 :           0 :     maxoff = PageGetMaxOffsetNumber(page);
    1689                 :           0 :     for (offnum = FirstOffsetNumber;
    1690         [ #  # ]:           0 :          offnum <= maxoff;
    1691                 :           0 :          offnum = OffsetNumberNext(offnum))
    1692                 :             :     {
    1693                 :           0 :         ItemId      itemId = PageGetItemId(page, offnum);
    1694                 :             : 
    1695         [ #  # ]:           0 :         if (ItemIdIsDead(itemId))
    1696                 :           0 :             deletable[ndeletable++] = offnum;
    1697                 :             :     }
    1698                 :             : 
    1699         [ #  # ]:           0 :     if (ndeletable > 0)
    1700                 :             :     {
    1701                 :           0 :         TransactionId snapshotConflictHorizon = InvalidTransactionId;
    1702                 :             : 
    1703   [ #  #  #  #  :           0 :         if (XLogStandbyInfoActive() && RelationNeedsWAL(rel))
          #  #  #  #  #  
                      # ]
    1704                 :             :             snapshotConflictHorizon =
    1705                 :           0 :                 index_compute_xid_horizon_for_tuples(rel, heapRel, buffer,
    1706                 :             :                                                      deletable, ndeletable);
    1707                 :             : 
    1708                 :           0 :         START_CRIT_SECTION();
    1709                 :             : 
    1710                 :           0 :         PageIndexMultiDelete(page, deletable, ndeletable);
    1711                 :             : 
    1712                 :             :         /*
    1713                 :             :          * Mark the page as not containing any LP_DEAD items.  This is not
    1714                 :             :          * certainly true (there might be some that have recently been marked,
    1715                 :             :          * but weren't included in our target-item list), but it will almost
    1716                 :             :          * always be true and it doesn't seem worth an additional page scan to
    1717                 :             :          * check it. Remember that F_HAS_GARBAGE is only a hint anyway.
    1718                 :             :          */
    1719                 :           0 :         GistClearPageHasGarbage(page);
    1720                 :             : 
    1721                 :           0 :         MarkBufferDirty(buffer);
    1722                 :             : 
    1723                 :             :         /* XLOG stuff */
    1724   [ #  #  #  #  :           0 :         if (RelationNeedsWAL(rel))
             #  #  #  # ]
    1725                 :           0 :         {
    1726                 :             :             XLogRecPtr  recptr;
    1727                 :             : 
    1728                 :           0 :             recptr = gistXLogDelete(buffer,
    1729                 :             :                                     deletable, ndeletable,
    1730                 :             :                                     snapshotConflictHorizon,
    1731                 :             :                                     heapRel);
    1732                 :             : 
    1733                 :           0 :             PageSetLSN(page, recptr);
    1734                 :             :         }
    1735                 :             :         else
    1736                 :           0 :             PageSetLSN(page, XLogGetFakeLSN(rel));
    1737                 :             : 
    1738                 :           0 :         END_CRIT_SECTION();
    1739                 :             :     }
    1740                 :             : 
    1741                 :             :     /*
    1742                 :             :      * Note: if we didn't find any LP_DEAD items, then the page's
    1743                 :             :      * F_HAS_GARBAGE hint bit is falsely set.  We do not bother expending a
    1744                 :             :      * separate write to clear it, however.  We will clear it when we split
    1745                 :             :      * the page.
    1746                 :             :      */
    1747                 :           0 : }
        

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