Re: index scan leads to result that is different from sec scan after upgrading to 8.3.4

Fixed, patch attached.


--
Teodor Sigaev                                   E-mail: teodor@sigaev.ru
                                                    WWW: http://www.sigaev.ru/
diff -c -r src.orig/backend/access/gist/gistget.c src/backend/access/gist/gistget.c
*** src.orig/backend/access/gist/gistget.c    2008-10-22 12:07:39.000000000 +0400
--- src/backend/access/gist/gistget.c    2008-10-22 15:13:23.000000000 +0400
***************
*** 49,55 ****

          for (offset = FirstOffsetNumber; offset <= maxoff; offset = OffsetNumberNext(offset))
          {
!                 IndexTuple    ituple = (IndexTuple) PageGetItem(p, PageGetItemId(p, offset));

              if (ItemPointerEquals(&(ituple->t_tid), iptr))
              {
--- 49,55 ----

          for (offset = FirstOffsetNumber; offset <= maxoff; offset = OffsetNumberNext(offset))
          {
!             IndexTuple    ituple = (IndexTuple) PageGetItem(p, PageGetItemId(p, offset));

              if (ItemPointerEquals(&(ituple->t_tid), iptr))
              {
***************
*** 157,163 ****
      {
          while( ntids < maxtids && so->curPageData < so->nPageData )
          {
!             tids[ ntids ] = scan->xs_ctup.t_self = so->pageData[ so->curPageData ];

              so->curPageData ++;
              ntids++;
--- 157,167 ----
      {
          while( ntids < maxtids && so->curPageData < so->nPageData )
          {
!             tids[ ntids ] = scan->xs_ctup.t_self = so->pageData[ so->curPageData ].heapPtr;
!             ItemPointerSet(&(so->curpos),
!                                BufferGetBlockNumber(so->curbuf),
!                                so->pageData[ so->curPageData ].pageOffset);
!

              so->curPageData ++;
              ntids++;
***************
*** 251,258 ****
              {
                  while( ntids < maxtids && so->curPageData < so->nPageData )
                  {
!                     tids[ ntids ] = scan->xs_ctup.t_self = so->pageData[ so->curPageData ];

                      so->curPageData ++;
                      ntids++;
                  }
--- 255,267 ----
              {
                  while( ntids < maxtids && so->curPageData < so->nPageData )
                  {
!                     tids[ ntids ] = scan->xs_ctup.t_self =
!                         so->pageData[ so->curPageData ].heapPtr;

+                     ItemPointerSet(&(so->curpos),
+                                    BufferGetBlockNumber(so->curbuf),
+                                    so->pageData[ so->curPageData ].pageOffset);
+
                      so->curPageData ++;
                      ntids++;
                  }
***************
*** 297,309 ****
                   * we can efficiently resume the index scan later.
                   */

-                 ItemPointerSet(&(so->curpos),
-                                BufferGetBlockNumber(so->curbuf), n);
-
                  if (!(ignore_killed_tuples && ItemIdIsDead(PageGetItemId(p, n))))
                  {
                      it = (IndexTuple) PageGetItem(p, PageGetItemId(p, n));
!                     so->pageData[ so->nPageData ] = it->t_tid;
                      so->nPageData ++;
                  }
              }
--- 306,316 ----
                   * we can efficiently resume the index scan later.
                   */

                  if (!(ignore_killed_tuples && ItemIdIsDead(PageGetItemId(p, n))))
                  {
                      it = (IndexTuple) PageGetItem(p, PageGetItemId(p, n));
!                     so->pageData[ so->nPageData ].heapPtr = it->t_tid;
!                     so->pageData[ so->nPageData ].pageOffset = n;
                      so->nPageData ++;
                  }
              }
diff -c -r src.orig/backend/access/gist/gistscan.c src/backend/access/gist/gistscan.c
*** src.orig/backend/access/gist/gistscan.c    2008-10-22 12:07:39.000000000 +0400
--- src/backend/access/gist/gistscan.c    2008-10-22 14:55:58.000000000 +0400
***************
*** 163,169 ****
      so->markNPageData = so->nPageData;
      so->markCurPageData = so->curPageData;
      if ( so->markNPageData > 0 )
!         memcpy( so->markPageData, so->pageData, sizeof(ItemPointerData) * so->markNPageData );

      PG_RETURN_VOID();
  }
--- 163,169 ----
      so->markNPageData = so->nPageData;
      so->markCurPageData = so->curPageData;
      if ( so->markNPageData > 0 )
!         memcpy( so->markPageData, so->pageData, sizeof(MatchedItemPtr) * so->markNPageData );

      PG_RETURN_VOID();
  }
***************
*** 217,223 ****
      so->nPageData = so->markNPageData;
      so->curPageData = so->markNPageData;
      if ( so->markNPageData > 0 )
!         memcpy( so->pageData, so->markPageData, sizeof(ItemPointerData) * so->markNPageData );

      PG_RETURN_VOID();
  }
--- 217,223 ----
      so->nPageData = so->markNPageData;
      so->curPageData = so->markNPageData;
      if ( so->markNPageData > 0 )
!         memcpy( so->pageData, so->markPageData, sizeof(MatchedItemPtr) * so->markNPageData );

      PG_RETURN_VOID();
  }
diff -c -r src.orig/include/access/gist_private.h src/include/access/gist_private.h
*** src.orig/include/access/gist_private.h    2008-10-22 12:07:50.000000000 +0400
--- src/include/access/gist_private.h    2008-10-22 15:00:24.000000000 +0400
***************
*** 60,65 ****
--- 60,71 ----
      TupleDesc    tupdesc;
  } GISTSTATE;

+ typedef struct MatchedItemPtr
+ {
+     ItemPointerData        heapPtr;
+     OffsetNumber        pageOffset; /* offset in index page */
+ } MatchedItemPtr;
+
  /*
   *    When we're doing a scan, we need to keep track of the parent stack
   *    for the marked and current items.
***************
*** 77,86 ****
      Buffer        markbuf;
      ItemPointerData markpos;

!     ItemPointerData    pageData[BLCKSZ/sizeof(IndexTupleData)];
      OffsetNumber    nPageData;
      OffsetNumber    curPageData;
!     ItemPointerData    markPageData[BLCKSZ/sizeof(IndexTupleData)];
      OffsetNumber    markNPageData;
      OffsetNumber    markCurPageData;
  } GISTScanOpaqueData;
--- 83,92 ----
      Buffer        markbuf;
      ItemPointerData markpos;

!     MatchedItemPtr    pageData[BLCKSZ/sizeof(IndexTupleData)];
      OffsetNumber    nPageData;
      OffsetNumber    curPageData;
!     MatchedItemPtr    markPageData[BLCKSZ/sizeof(IndexTupleData)];
      OffsetNumber    markNPageData;
      OffsetNumber    markCurPageData;
  } GISTScanOpaqueData;