currentItemData refactoring - Mailing list pgsql-patches

Here's a patch to remove currentItemData & currentMarkpos from
IndexScanDesc, and add equivalent fields in access method specific
opaque structs for those access methods that need them. That makes the
index am API cleaner.

--
  Heikki Linnakangas
  EnterpriseDB   http://www.enterprisedb.com

Index: src/backend/access/gist/gistget.c
===================================================================
RCS file: /home/hlinnaka/pgcvsrepository/pgsql/src/backend/access/gist/gistget.c,v
retrieving revision 1.60
diff -c -r1.60 gistget.c
*** src/backend/access/gist/gistget.c    14 Jul 2006 14:52:16 -0000    1.60
--- src/backend/access/gist/gistget.c    12 Sep 2006 15:37:48 -0000
***************
*** 106,113 ****
       * If we have produced an index tuple in the past and the executor has
       * informed us we need to mark it as "killed", do so now.
       */
!     if (scan->kill_prior_tuple && ItemPointerIsValid(&(scan->currentItemData)))
!         killtuple(scan->indexRelation, so, &(scan->currentItemData));

      /*
       * Get the next tuple that matches the search key. If asked to skip killed
--- 106,113 ----
       * If we have produced an index tuple in the past and the executor has
       * informed us we need to mark it as "killed", do so now.
       */
!     if (scan->kill_prior_tuple && ItemPointerIsValid(&(so->curpos)))
!         killtuple(scan->indexRelation, so, &(so->curpos));

      /*
       * Get the next tuple that matches the search key. If asked to skip killed
***************
*** 151,157 ****

      so = (GISTScanOpaque) scan->opaque;

!     if (ItemPointerIsValid(&scan->currentItemData) == false)
      {
          /* Being asked to fetch the first entry, so start at the root */
          Assert(so->curbuf == InvalidBuffer);
--- 151,157 ----

      so = (GISTScanOpaque) scan->opaque;

!     if (ItemPointerIsValid(&so->curpos) == false)
      {
          /* Being asked to fetch the first entry, so start at the root */
          Assert(so->curbuf == InvalidBuffer);
***************
*** 226,232 ****
          }

          if (!GistPageIsLeaf(p) || resetoffset ||
!             !ItemPointerIsValid(&scan->currentItemData))
          {
              if (ScanDirectionIsBackward(dir))
                  n = PageGetMaxOffsetNumber(p);
--- 226,232 ----
          }

          if (!GistPageIsLeaf(p) || resetoffset ||
!             !ItemPointerIsValid(&so->curpos))
          {
              if (ScanDirectionIsBackward(dir))
                  n = PageGetMaxOffsetNumber(p);
***************
*** 235,241 ****
          }
          else
          {
!             n = ItemPointerGetOffsetNumber(&(scan->currentItemData));

              if (ScanDirectionIsBackward(dir))
                  n = OffsetNumberPrev(n);
--- 235,241 ----
          }
          else
          {
!             n = ItemPointerGetOffsetNumber(&(so->curpos));

              if (ScanDirectionIsBackward(dir))
                  n = OffsetNumberPrev(n);
***************
*** 285,291 ****
                   * we can efficiently resume the index scan later.
                   */

!                 ItemPointerSet(&(scan->currentItemData),
                                 BufferGetBlockNumber(so->curbuf), n);

                  if (!(ignore_killed_tuples && ItemIdDeleted(PageGetItemId(p, n))))
--- 285,291 ----
                   * we can efficiently resume the index scan later.
                   */

!                 ItemPointerSet(&(so->curpos),
                                 BufferGetBlockNumber(so->curbuf), n);

                  if (!(ignore_killed_tuples && ItemIdDeleted(PageGetItemId(p, n))))
Index: src/backend/access/gist/gistscan.c
===================================================================
RCS file: /home/hlinnaka/pgcvsrepository/pgsql/src/backend/access/gist/gistscan.c,v
retrieving revision 1.64
diff -c -r1.64 gistscan.c
*** src/backend/access/gist/gistscan.c    14 Jul 2006 14:52:16 -0000    1.64
--- src/backend/access/gist/gistscan.c    12 Sep 2006 15:38:52 -0000
***************
*** 42,53 ****
      GISTScanOpaque so;
      int            i;

-     /*
-      * Clear all the pointers.
-      */
-     ItemPointerSetInvalid(&scan->currentItemData);
-     ItemPointerSetInvalid(&scan->currentMarkData);
-
      so = (GISTScanOpaque) scan->opaque;
      if (so != NULL)
      {
--- 42,47 ----
***************
*** 82,87 ****
--- 76,88 ----
          scan->opaque = so;
      }

+
+     /*
+      * Clear all the pointers.
+      */
+     ItemPointerSetInvalid(&so->curpos);
+     ItemPointerSetInvalid(&so->markpos);
+
      /* Update scan key, if a new one is given */
      if (key && scan->numberOfKeys > 0)
      {
***************
*** 111,117 ****
                 *n,
                 *tmp;

!     scan->currentMarkData = scan->currentItemData;
      so = (GISTScanOpaque) scan->opaque;
      if (so->flags & GS_CURBEFORE)
          so->flags |= GS_MRKBEFORE;
--- 112,118 ----
                 *n,
                 *tmp;

!     so->markpos = so->curpos;
      so = (GISTScanOpaque) scan->opaque;
      if (so->flags & GS_CURBEFORE)
          so->flags |= GS_MRKBEFORE;
***************
*** 160,166 ****
                 *n,
                 *tmp;

!     scan->currentItemData = scan->currentMarkData;
      so = (GISTScanOpaque) scan->opaque;
      if (so->flags & GS_MRKBEFORE)
          so->flags |= GS_CURBEFORE;
--- 161,167 ----
                 *n,
                 *tmp;

!     so->curpos = so->markpos;
      so = (GISTScanOpaque) scan->opaque;
      if (so->flags & GS_MRKBEFORE)
          so->flags |= GS_CURBEFORE;
Index: src/backend/access/hash/hash.c
===================================================================
RCS file: /home/hlinnaka/pgcvsrepository/pgsql/src/backend/access/hash/hash.c,v
retrieving revision 1.91
diff -c -r1.91 hash.c
*** src/backend/access/hash/hash.c    14 Jul 2006 14:52:17 -0000    1.91
--- src/backend/access/hash/hash.c    12 Sep 2006 15:45:32 -0000
***************
*** 185,191 ****
       * appropriate direction.  If we haven't done so yet, we call a routine to
       * get the first item in the scan.
       */
!     if (ItemPointerIsValid(&(scan->currentItemData)))
      {
          /*
           * Check to see if we should kill the previously-fetched tuple.
--- 185,191 ----
       * appropriate direction.  If we haven't done so yet, we call a routine to
       * get the first item in the scan.
       */
!     if (ItemPointerIsValid(&(so->hashso_curpos)))
      {
          /*
           * Check to see if we should kill the previously-fetched tuple.
***************
*** 195,201 ****
              /*
               * Yes, so mark it by setting the LP_DELETE bit in the item flags.
               */
!             offnum = ItemPointerGetOffsetNumber(&(scan->currentItemData));
              page = BufferGetPage(so->hashso_curbuf);
              PageGetItemId(page, offnum)->lp_flags |= LP_DELETE;

--- 195,201 ----
              /*
               * Yes, so mark it by setting the LP_DELETE bit in the item flags.
               */
!             offnum = ItemPointerGetOffsetNumber(&(so->hashso_curpos));
              page = BufferGetPage(so->hashso_curbuf);
              PageGetItemId(page, offnum)->lp_flags |= LP_DELETE;

***************
*** 222,228 ****
      {
          while (res)
          {
!             offnum = ItemPointerGetOffsetNumber(&(scan->currentItemData));
              page = BufferGetPage(so->hashso_curbuf);
              if (!ItemIdDeleted(PageGetItemId(page, offnum)))
                  break;
--- 222,228 ----
      {
          while (res)
          {
!             offnum = ItemPointerGetOffsetNumber(&(so->hashso_curpos));
              page = BufferGetPage(so->hashso_curbuf);
              if (!ItemIdDeleted(PageGetItemId(page, offnum)))
                  break;
***************
*** 269,275 ****
          /*
           * Start scan, or advance to next tuple.
           */
!         if (ItemPointerIsValid(&(scan->currentItemData)))
              res = _hash_next(scan, ForwardScanDirection);
          else
              res = _hash_first(scan, ForwardScanDirection);
--- 269,275 ----
          /*
           * Start scan, or advance to next tuple.
           */
!         if (ItemPointerIsValid(&(so->hashso_curpos)))
              res = _hash_next(scan, ForwardScanDirection);
          else
              res = _hash_first(scan, ForwardScanDirection);
***************
*** 284,290 ****
                  Page        page;
                  OffsetNumber offnum;

!                 offnum = ItemPointerGetOffsetNumber(&(scan->currentItemData));
                  page = BufferGetPage(so->hashso_curbuf);
                  if (!ItemIdDeleted(PageGetItemId(page, offnum)))
                      break;
--- 284,290 ----
                  Page        page;
                  OffsetNumber offnum;

!                 offnum = ItemPointerGetOffsetNumber(&(so->hashso_curpos));
                  page = BufferGetPage(so->hashso_curbuf);
                  if (!ItemIdDeleted(PageGetItemId(page, offnum)))
                      break;
***************
*** 326,331 ****
--- 326,335 ----
      so->hashso_bucket_blkno = 0;
      so->hashso_curbuf = so->hashso_mrkbuf = InvalidBuffer;
      scan->opaque = so;
+     /* set positions invalid (this will cause _hash_first call) */
+     ItemPointerSetInvalid(&(so->hashso_curpos));
+     ItemPointerSetInvalid(&(so->hashso_mrkpos));
+

      /* register scan in case we change pages it's using */
      _hash_regscan(scan);
***************
*** 360,370 ****
          if (so->hashso_bucket_blkno)
              _hash_droplock(rel, so->hashso_bucket_blkno, HASH_SHARE);
          so->hashso_bucket_blkno = 0;
-     }

!     /* set positions invalid (this will cause _hash_first call) */
!     ItemPointerSetInvalid(&(scan->currentItemData));
!     ItemPointerSetInvalid(&(scan->currentMarkData));

      /* Update scan key, if a new one is given */
      if (scankey && scan->numberOfKeys > 0)
--- 364,374 ----
          if (so->hashso_bucket_blkno)
              _hash_droplock(rel, so->hashso_bucket_blkno, HASH_SHARE);
          so->hashso_bucket_blkno = 0;

!         /* set positions invalid (this will cause _hash_first call) */
!         ItemPointerSetInvalid(&(so->hashso_curpos));
!         ItemPointerSetInvalid(&(so->hashso_mrkpos));
!     }

      /* Update scan key, if a new one is given */
      if (scankey && scan->numberOfKeys > 0)
***************
*** 406,415 ****
          _hash_droplock(rel, so->hashso_bucket_blkno, HASH_SHARE);
      so->hashso_bucket_blkno = 0;

-     /* be tidy */
-     ItemPointerSetInvalid(&(scan->currentItemData));
-     ItemPointerSetInvalid(&(scan->currentMarkData));
-
      pfree(so);
      scan->opaque = NULL;

--- 410,415 ----
***************
*** 430,443 ****
      if (BufferIsValid(so->hashso_mrkbuf))
          _hash_dropbuf(rel, so->hashso_mrkbuf);
      so->hashso_mrkbuf = InvalidBuffer;
!     ItemPointerSetInvalid(&(scan->currentMarkData));

!     /* bump pin count on currentItemData and copy to currentMarkData */
!     if (ItemPointerIsValid(&(scan->currentItemData)))
      {
          IncrBufferRefCount(so->hashso_curbuf);
          so->hashso_mrkbuf = so->hashso_curbuf;
!         scan->currentMarkData = scan->currentItemData;
      }

      PG_RETURN_VOID();
--- 430,443 ----
      if (BufferIsValid(so->hashso_mrkbuf))
          _hash_dropbuf(rel, so->hashso_mrkbuf);
      so->hashso_mrkbuf = InvalidBuffer;
!     ItemPointerSetInvalid(&(so->hashso_mrkpos));

!     /* bump pin count on current buffer and copy to marked buffer */
!     if (ItemPointerIsValid(&(so->hashso_curpos)))
      {
          IncrBufferRefCount(so->hashso_curbuf);
          so->hashso_mrkbuf = so->hashso_curbuf;
!         so->hashso_mrkpos = so->hashso_curpos;
      }

      PG_RETURN_VOID();
***************
*** 457,470 ****
      if (BufferIsValid(so->hashso_curbuf))
          _hash_dropbuf(rel, so->hashso_curbuf);
      so->hashso_curbuf = InvalidBuffer;
!     ItemPointerSetInvalid(&(scan->currentItemData));

!     /* bump pin count on currentMarkData and copy to currentItemData */
!     if (ItemPointerIsValid(&(scan->currentMarkData)))
      {
          IncrBufferRefCount(so->hashso_mrkbuf);
          so->hashso_curbuf = so->hashso_mrkbuf;
!         scan->currentItemData = scan->currentMarkData;
      }

      PG_RETURN_VOID();
--- 457,470 ----
      if (BufferIsValid(so->hashso_curbuf))
          _hash_dropbuf(rel, so->hashso_curbuf);
      so->hashso_curbuf = InvalidBuffer;
!     ItemPointerSetInvalid(&(so->hashso_curpos));

!     /* bump pin count on marked buffer and copy to current buffer */
!     if (ItemPointerIsValid(&(so->hashso_mrkpos)))
      {
          IncrBufferRefCount(so->hashso_mrkbuf);
          so->hashso_curbuf = so->hashso_mrkbuf;
!         so->hashso_curpos = so->hashso_mrkpos;
      }

      PG_RETURN_VOID();
Index: src/backend/access/hash/hashsearch.c
===================================================================
RCS file: /home/hlinnaka/pgcvsrepository/pgsql/src/backend/access/hash/hashsearch.c,v
retrieving revision 1.45
diff -c -r1.45 hashsearch.c
*** src/backend/access/hash/hashsearch.c    14 Jul 2006 14:52:17 -0000    1.45
--- src/backend/access/hash/hashsearch.c    12 Sep 2006 15:44:45 -0000
***************
*** 21,27 ****
  /*
   *    _hash_next() -- Get the next item in a scan.
   *
!  *        On entry, we have a valid currentItemData in the scan, and a
   *        pin and read lock on the page that contains that item.
   *        We find the next item in the scan, if any.
   *        On success exit, we have the page containing the next item
--- 21,27 ----
  /*
   *    _hash_next() -- Get the next item in a scan.
   *
!  *        On entry, we have a valid hashso_curpos in the scan, and a
   *        pin and read lock on the page that contains that item.
   *        We find the next item in the scan, if any.
   *        On success exit, we have the page containing the next item
***************
*** 49,55 ****
          return false;

      /* if we're here, _hash_step found a valid tuple */
!     current = &(scan->currentItemData);
      offnum = ItemPointerGetOffsetNumber(current);
      _hash_checkpage(rel, buf, LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
      page = BufferGetPage(buf);
--- 49,55 ----
          return false;

      /* if we're here, _hash_step found a valid tuple */
!     current = &(so->hashso_curpos);
      offnum = ItemPointerGetOffsetNumber(current);
      _hash_checkpage(rel, buf, LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
      page = BufferGetPage(buf);
***************
*** 129,135 ****

      pgstat_count_index_scan(&scan->xs_pgstat_info);

!     current = &(scan->currentItemData);
      ItemPointerSetInvalid(current);

      /*
--- 129,135 ----

      pgstat_count_index_scan(&scan->xs_pgstat_info);

!     current = &(so->hashso_curpos);
      ItemPointerSetInvalid(current);

      /*
***************
*** 224,230 ****
   *    _hash_step() -- step to the next valid item in a scan in the bucket.
   *
   *        If no valid record exists in the requested direction, return
!  *        false.    Else, return true and set the CurrentItemData for the
   *        scan to the right thing.
   *
   *        'bufP' points to the current buffer, which is pinned and read-locked.
--- 224,230 ----
   *    _hash_step() -- step to the next valid item in a scan in the bucket.
   *
   *        If no valid record exists in the requested direction, return
!  *        false.    Else, return true and set the hashso_curpos for the
   *        scan to the right thing.
   *
   *        'bufP' points to the current buffer, which is pinned and read-locked.
***************
*** 245,251 ****
      BlockNumber blkno;
      IndexTuple    itup;

!     current = &(scan->currentItemData);

      buf = *bufP;
      _hash_checkpage(rel, buf, LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
--- 245,251 ----
      BlockNumber blkno;
      IndexTuple    itup;

!     current = &(so->hashso_curpos);

      buf = *bufP;
      _hash_checkpage(rel, buf, LH_BUCKET_PAGE | LH_OVERFLOW_PAGE);
Index: src/backend/access/index/genam.c
===================================================================
RCS file: /home/hlinnaka/pgcvsrepository/pgsql/src/backend/access/index/genam.c,v
retrieving revision 1.58
diff -c -r1.58 genam.c
*** src/backend/access/index/genam.c    31 Jul 2006 20:08:59 -0000    1.58
--- src/backend/access/index/genam.c    12 Sep 2006 15:45:54 -0000
***************
*** 92,100 ****

      scan->opaque = NULL;

-     ItemPointerSetInvalid(&scan->currentItemData);
-     ItemPointerSetInvalid(&scan->currentMarkData);
-
      ItemPointerSetInvalid(&scan->xs_ctup.t_self);
      scan->xs_ctup.t_data = NULL;
      scan->xs_cbuf = InvalidBuffer;
--- 92,97 ----
Index: src/include/access/gist_private.h
===================================================================
RCS file: /home/hlinnaka/pgcvsrepository/pgsql/src/include/access/gist_private.h,v
retrieving revision 1.23
diff -c -r1.23 gist_private.h
*** src/include/access/gist_private.h    7 Aug 2006 16:57:57 -0000    1.23
--- src/include/access/gist_private.h    12 Sep 2006 15:36:30 -0000
***************
*** 72,78 ****
--- 72,80 ----
      GISTSTATE  *giststate;
      MemoryContext tempCxt;
      Buffer        curbuf;
+     ItemPointerData curpos;
      Buffer        markbuf;
+     ItemPointerData markpos;
  } GISTScanOpaqueData;

  typedef GISTScanOpaqueData *GISTScanOpaque;
Index: src/include/access/hash.h
===================================================================
RCS file: /home/hlinnaka/pgcvsrepository/pgsql/src/include/access/hash.h,v
retrieving revision 1.73
diff -c -r1.73 hash.h
*** src/include/access/hash.h    13 Jul 2006 16:49:19 -0000    1.73
--- src/include/access/hash.h    12 Sep 2006 15:39:28 -0000
***************
*** 97,102 ****
--- 97,106 ----
       */
      Buffer        hashso_curbuf;
      Buffer        hashso_mrkbuf;
+
+     /* Current and marked position of the scan */
+     ItemPointerData hashso_curpos;
+     ItemPointerData hashso_mrkpos;
  } HashScanOpaqueData;

  typedef HashScanOpaqueData *HashScanOpaque;
Index: src/include/access/nbtree.h
===================================================================
RCS file: /home/hlinnaka/pgcvsrepository/pgsql/src/include/access/nbtree.h,v
retrieving revision 1.104
diff -c -r1.104 nbtree.h
*** src/include/access/nbtree.h    24 Aug 2006 01:18:34 -0000    1.104
--- src/include/access/nbtree.h    12 Sep 2006 15:55:17 -0000
***************
*** 383,391 ****
   * items were killed, we re-lock the page to mark them killed, then unlock.
   * Finally we drop the pin and step to the next page in the appropriate
   * direction.
-  *
-  * NOTE: in this implementation, btree does not use or set the
-  * currentItemData and currentMarkData fields of IndexScanDesc at all.
   */

  typedef struct BTScanPosItem    /* what we remember about each match */
--- 383,388 ----
Index: src/include/access/relscan.h
===================================================================
RCS file: /home/hlinnaka/pgcvsrepository/pgsql/src/include/access/relscan.h,v
retrieving revision 1.49
diff -c -r1.49 relscan.h
*** src/include/access/relscan.h    31 Jul 2006 20:09:05 -0000    1.49
--- src/include/access/relscan.h    12 Sep 2006 15:52:50 -0000
***************
*** 69,77 ****

      /* index access method's private state */
      void       *opaque;            /* access-method-specific info */
-     /* these fields are used by some but not all AMs: */
-     ItemPointerData currentItemData;    /* current index pointer */
-     ItemPointerData currentMarkData;    /* marked position, if any */

      /*
       * xs_ctup/xs_cbuf are valid after a successful index_getnext. After
--- 69,74 ----