HOT updates. When we update a tuple without changing any of its indexed

columns, and the new version can be stored on the same heap page, we no longer
generate extra index entries for the new version.  Instead, index searches
follow the HOT-chain links to ensure they find the correct tuple version.

In addition, this patch introduces the ability to "prune" dead tuples on a
per-page basis, without having to do a complete VACUUM pass to recover space.
VACUUM is still needed to clean up dead index entries, however.

Pavan Deolasee, with help from a bunch of other people.

3 files changed, 6 insertions, 6 deletions

diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index fce9a94ebae..0c1b94d7d38 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/gist/gist.c,v 1.146 2007/09/12 22:10:25 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/gist/gist.c,v 1.147 2007/09/20 17:56:30 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -366,7 +366,7 @@ gistplacetopage(GISTInsertState *state, GISTSTATE *giststate)
 			data = (char *) (ptr->list);
 			for (i = 0; i < ptr->block.num; i++)
 			{
-				if (PageAddItem(ptr->page, (Item) data, IndexTupleSize((IndexTuple) data), i + FirstOffsetNumber, false) == InvalidOffsetNumber)
+				if (PageAddItem(ptr->page, (Item) data, IndexTupleSize((IndexTuple) data), i + FirstOffsetNumber, false, false) == InvalidOffsetNumber)
 					elog(ERROR, "failed to add item to index page in \"%s\"", RelationGetRelationName(state->r));
 				data += IndexTupleSize((IndexTuple) data);
 			}
diff --git a/src/backend/access/gist/gistutil.c b/src/backend/access/gist/gistutil.c
index 6d4f31d53b2..409377d1d14 100644
--- a/src/backend/access/gist/gistutil.c
+++ b/src/backend/access/gist/gistutil.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *			$PostgreSQL: pgsql/src/backend/access/gist/gistutil.c,v 1.23 2007/09/12 22:10:25 tgl Exp $
+ *			$PostgreSQL: pgsql/src/backend/access/gist/gistutil.c,v 1.24 2007/09/20 17:56:30 tgl Exp $
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
@@ -42,7 +42,7 @@ gistfillbuffer(Relation r, Page page, IndexTuple *itup,
 	for (i = 0; i < len; i++)
 	{
 		l = PageAddItem(page, (Item) itup[i], IndexTupleSize(itup[i]),
-						off, false);
+						off, false, false);
 		if (l == InvalidOffsetNumber)
 			elog(ERROR, "failed to add item to index page in \"%s\"",
 				 RelationGetRelationName(r));
diff --git a/src/backend/access/gist/gistvacuum.c b/src/backend/access/gist/gistvacuum.c
index 0abd0197ad3..212995e7c57 100644
--- a/src/backend/access/gist/gistvacuum.c
+++ b/src/backend/access/gist/gistvacuum.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/gist/gistvacuum.c,v 1.31 2007/09/12 22:10:25 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/gist/gistvacuum.c,v 1.32 2007/09/20 17:56:30 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -201,7 +201,7 @@ vacuumSplitPage(GistVacuum *gv, Page tempPage, Buffer buffer, IndexTuple *addon,
 		data = (char *) (ptr->list);
 		for (i = 0; i < ptr->block.num; i++)
 		{
-			if (PageAddItem(ptr->page, (Item) data, IndexTupleSize((IndexTuple) data), i + FirstOffsetNumber, false) == InvalidOffsetNumber)
+			if (PageAddItem(ptr->page, (Item) data, IndexTupleSize((IndexTuple) data), i + FirstOffsetNumber, false, false) == InvalidOffsetNumber)
 				elog(ERROR, "failed to add item to index page in \"%s\"", RelationGetRelationName(gv->index));
 			data += IndexTupleSize((IndexTuple) data);
 		}