diff --git a/src/backend/access/gin/gindatapage.c b/src/backend/access/gin/gindatapage.c
index a872d44880c7f04ffafbff40a98ad95e9a4a71ff..22199102ddcc0554587bd3122e292af18a06ac20 100644
--- a/src/backend/access/gin/gindatapage.c
+++ b/src/backend/access/gin/gindatapage.c
@@ -8,7 +8,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/access/gin/gindatapage.c,v 1.14 2009/03/24 20:17:10 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/gin/gindatapage.c,v 1.15 2009/06/06 02:39:40 tgl Exp $
*-------------------------------------------------------------------------
*/
@@ -32,10 +32,14 @@ compareItemPointers(ItemPointer a, ItemPointer b)
}
/*
- * Merge two ordered array of itempointer
+ * Merge two ordered arrays of itempointers, eliminating any duplicates.
+ * Returns the number of items in the result.
+ * Caller is responsible that there is enough space at *dst.
*/
-void
-MergeItemPointers(ItemPointerData *dst, ItemPointerData *a, uint32 na, ItemPointerData *b, uint32 nb)
+uint32
+MergeItemPointers(ItemPointerData *dst,
+ ItemPointerData *a, uint32 na,
+ ItemPointerData *b, uint32 nb)
{
ItemPointerData *dptr = dst;
ItemPointerData *aptr = a,
@@ -62,6 +66,8 @@ MergeItemPointers(ItemPointerData *dst, ItemPointerData *a, uint32 na, ItemPoint
while (bptr - b < nb)
*dptr++ = *bptr++;
+
+ return dptr - dst;
}
/*
diff --git a/src/backend/access/gin/ginentrypage.c b/src/backend/access/gin/ginentrypage.c
index e16575bc8130e3efb6d35043e8fa176c14b5d3e9..f35994db953eba5962503695221dd8b166169e69 100644
--- a/src/backend/access/gin/ginentrypage.c
+++ b/src/backend/access/gin/ginentrypage.c
@@ -8,7 +8,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/access/gin/ginentrypage.c,v 1.19 2009/01/01 17:23:34 momjian Exp $
+ * $PostgreSQL: pgsql/src/backend/access/gin/ginentrypage.c,v 1.20 2009/06/06 02:39:40 tgl Exp $
*-------------------------------------------------------------------------
*/
@@ -20,28 +20,33 @@
#include "utils/rel.h"
/*
- * forms tuple for entry tree. On leaf page, Index tuple has
- * non-traditional layout. Tuple may contain posting list or
- * root blocknumber of posting tree. Macros GinIsPostingTre: (itup) / GinSetPostingTree(itup, blkno)
+ * Form a tuple for entry tree.
+ *
+ * On leaf pages, Index tuple has non-traditional layout. Tuple may contain
+ * posting list or root blocknumber of posting tree.
+ * Macros: GinIsPostingTree(itup) / GinSetPostingTree(itup, blkno)
* 1) Posting list
- * - itup->t_info & INDEX_SIZE_MASK contains size of tuple as usual
+ * - itup->t_info & INDEX_SIZE_MASK contains total size of tuple as usual
* - ItemPointerGetBlockNumber(&itup->t_tid) contains original
* size of tuple (without posting list).
- * Macroses: GinGetOrigSizePosting(itup) / GinSetOrigSizePosting(itup,n)
+ * Macros: GinGetOrigSizePosting(itup) / GinSetOrigSizePosting(itup,n)
* - ItemPointerGetOffsetNumber(&itup->t_tid) contains number
- * of elements in posting list (number of heap itempointer)
- * Macroses: GinGetNPosting(itup) / GinSetNPosting(itup,n)
- * - After usual part of tuple there is a posting list
+ * of elements in posting list (number of heap itempointers)
+ * Macros: GinGetNPosting(itup) / GinSetNPosting(itup,n)
+ * - After standard part of tuple there is a posting list, ie, array
+ * of heap itempointers
* Macros: GinGetPosting(itup)
* 2) Posting tree
* - itup->t_info & INDEX_SIZE_MASK contains size of tuple as usual
* - ItemPointerGetBlockNumber(&itup->t_tid) contains block number of
* root of posting tree
- * - ItemPointerGetOffsetNumber(&itup->t_tid) contains magic number GIN_TREE_POSTING
+ * - ItemPointerGetOffsetNumber(&itup->t_tid) contains magic number
+ * GIN_TREE_POSTING, which distinguishes this from posting-list case
*
- * Storage of attributes of tuple are different for single and multicolumn index.
- * For single-column index tuple stores only value to be indexed and for
- * multicolumn variant it stores two attributes: column number of value and value.
+ * Attributes of an index tuple are different for single and multicolumn index.
+ * For single-column case, index tuple stores only value to be indexed.
+ * For multicolumn case, it stores two attributes: column number of value
+ * and value.
*/
IndexTuple
GinFormTuple(GinState *ginstate, OffsetNumber attnum, Datum key, ItemPointerData *ipd, uint32 nipd)
@@ -89,6 +94,28 @@ GinFormTuple(GinState *ginstate, OffsetNumber attnum, Datum key, ItemPointerData
return itup;
}
+/*
+ * Sometimes we reduce the number of posting list items in a tuple after
+ * having built it with GinFormTuple. This function adjusts the size
+ * fields to match.
+ */
+void
+GinShortenTuple(IndexTuple itup, uint32 nipd)
+{
+ uint32 newsize;
+
+ Assert(nipd <= GinGetNPosting(itup));
+
+ newsize = MAXALIGN(SHORTALIGN(GinGetOrigSizePosting(itup)) + sizeof(ItemPointerData) * nipd);
+
+ Assert(newsize <= (itup->t_info & INDEX_SIZE_MASK));
+
+ itup->t_info &= ~INDEX_SIZE_MASK;
+ itup->t_info |= newsize;
+
+ GinSetNPosting(itup, nipd);
+}
+
/*
* Entry tree is a "static", ie tuple never deletes from it,
* so we don't use right bound, we use rightest key instead.
diff --git a/src/backend/access/gin/gininsert.c b/src/backend/access/gin/gininsert.c
index f6a348eb85d88f98ee5aa4f2508aa9c1f03f2d57..ef3d4bbb0320e2b881042981af6d96eaaa8f2709 100644
--- a/src/backend/access/gin/gininsert.c
+++ b/src/backend/access/gin/gininsert.c
@@ -8,7 +8,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/access/gin/gininsert.c,v 1.20 2009/03/24 22:06:03 tgl Exp $
+ * $PostgreSQL: pgsql/src/backend/access/gin/gininsert.c,v 1.21 2009/06/06 02:39:40 tgl Exp $
*-------------------------------------------------------------------------
*/
@@ -102,17 +102,19 @@ addItemPointersToTuple(Relation index, GinState *ginstate, GinBtreeStack *stack,
{
Datum key = gin_index_getattr(ginstate, old);
OffsetNumber attnum = gintuple_get_attrnum(ginstate, old);
- IndexTuple res = GinFormTuple(ginstate, attnum, key, NULL, nitem + GinGetNPosting(old));
+ IndexTuple res = GinFormTuple(ginstate, attnum, key,
+ NULL, nitem + GinGetNPosting(old));
if (res)
{
/* good, small enough */
- MergeItemPointers(GinGetPosting(res),
- GinGetPosting(old), GinGetNPosting(old),
- items, nitem
- );
+ uint32 newnitem;
- GinSetNPosting(res, nitem + GinGetNPosting(old));
+ newnitem = MergeItemPointers(GinGetPosting(res),
+ GinGetPosting(old), GinGetNPosting(old),
+ items, nitem);
+ /* merge might have eliminated some duplicate items */
+ GinShortenTuple(res, newnitem);
}
else
{
diff --git a/src/include/access/gin.h b/src/include/access/gin.h
index 49a14b6290644141e80b3ca88569720db0da2852..366fc370b0a0c51a15160f4afbe0c4420e6f65ab 100644
--- a/src/include/access/gin.h
+++ b/src/include/access/gin.h
@@ -4,7 +4,7 @@
*
* Copyright (c) 2006-2009, PostgreSQL Global Development Group
*
- * $PostgreSQL: pgsql/src/include/access/gin.h,v 1.32 2009/06/05 18:50:47 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/access/gin.h,v 1.33 2009/06/06 02:39:40 tgl Exp $
*--------------------------------------------------------------------------
*/
#ifndef GIN_H
@@ -435,6 +435,7 @@ extern void findParents(GinBtree btree, GinBtreeStack *stack, BlockNumber rootBl
/* ginentrypage.c */
extern IndexTuple GinFormTuple(GinState *ginstate, OffsetNumber attnum, Datum key,
ItemPointerData *ipd, uint32 nipd);
+extern void GinShortenTuple(IndexTuple itup, uint32 nipd);
extern void prepareEntryScan(GinBtree btree, Relation index, OffsetNumber attnum,
Datum value, GinState *ginstate);
extern void entryFillRoot(GinBtree btree, Buffer root, Buffer lbuf, Buffer rbuf);
@@ -442,7 +443,7 @@ extern IndexTuple ginPageGetLinkItup(Buffer buf);
/* gindatapage.c */
extern int compareItemPointers(ItemPointer a, ItemPointer b);
-extern void MergeItemPointers(ItemPointerData *dst,
+extern uint32 MergeItemPointers(ItemPointerData *dst,
ItemPointerData *a, uint32 na,
ItemPointerData *b, uint32 nb);