Change SearchSysCache coding conventions so that a reference count is

maintained for each cache entry.  A cache entry will not be freed until
the matching ReleaseSysCache call has been executed.  This eliminates
worries about cache entries getting dropped while still in use.  See
my posting to pg-hackers of even date for more info.

1 files changed, 15 insertions, 14 deletions

diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index d7bfeb1287d..d8e9005e933 100644
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -6,7 +6,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/gist/gist.c,v 1.64 2000/11/08 22:09:53 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/gist/gist.c,v 1.65 2000/11/16 22:30:15 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1140,6 +1140,7 @@ initGISTstate(GISTSTATE *giststate, Relation index)
 				equal_proc;
 	HeapTuple	htup;
 	Form_pg_index itupform;
+	Oid			indexrelid;
 
 	consistent_proc = index_getprocid(index, 1, GIST_CONSISTENT_PROC);
 	union_proc = index_getprocid(index, 1, GIST_UNION_PROC);
@@ -1157,32 +1158,32 @@ initGISTstate(GISTSTATE *giststate, Relation index)
 	fmgr_info(equal_proc, &giststate->equalFn);
 
 	/* see if key type is different from type of attribute being indexed */
-	htup = SearchSysCacheTuple(INDEXRELID,
-							   ObjectIdGetDatum(RelationGetRelid(index)),
-							   0, 0, 0);
-	itupform = (Form_pg_index) GETSTRUCT(htup);
+	htup = SearchSysCache(INDEXRELID,
+						  ObjectIdGetDatum(RelationGetRelid(index)),
+						  0, 0, 0);
 	if (!HeapTupleIsValid(htup))
 		elog(ERROR, "initGISTstate: index %u not found",
 			 RelationGetRelid(index));
+	itupform = (Form_pg_index) GETSTRUCT(htup);
 	giststate->haskeytype = itupform->indhaskeytype;
+	indexrelid = itupform->indexrelid;
+	ReleaseSysCache(htup);
+
 	if (giststate->haskeytype)
 	{
 		/* key type is different -- is it byval? */
-		htup = SearchSysCacheTuple(ATTNUM,
-								   ObjectIdGetDatum(itupform->indexrelid),
-								   UInt16GetDatum(FirstOffsetNumber),
-								   0, 0);
+		htup = SearchSysCache(ATTNUM,
+							  ObjectIdGetDatum(indexrelid),
+							  UInt16GetDatum(FirstOffsetNumber),
+							  0, 0);
 		if (!HeapTupleIsValid(htup))
-		{
 			elog(ERROR, "initGISTstate: no attribute tuple %u %d",
-				 itupform->indexrelid, FirstOffsetNumber);
-			return;
-		}
+				 indexrelid, FirstOffsetNumber);
 		giststate->keytypbyval = (((Form_pg_attribute) htup)->attbyval);
+		ReleaseSysCache(htup);
 	}
 	else
 		giststate->keytypbyval = FALSE;
-	return;
 }