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.

3 files changed, 36 insertions, 22 deletions

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index 4069ed66e58..bfb97bc1eb5 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.100 2000/11/12 00:36:58 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.101 2000/11/16 22:30:24 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -396,17 +396,19 @@ create_indexscan_plan(Query *root,
 		HeapTuple	indexTuple;
 		Form_pg_index index;
 
-		indexTuple = SearchSysCacheTuple(INDEXRELID,
-										 ObjectIdGetDatum(lfirsti(ixid)),
-										 0, 0, 0);
+		indexTuple = SearchSysCache(INDEXRELID,
+									ObjectIdGetDatum(lfirsti(ixid)),
+									0, 0, 0);
 		if (!HeapTupleIsValid(indexTuple))
 			elog(ERROR, "create_plan: index %u not found", lfirsti(ixid));
 		index = (Form_pg_index) GETSTRUCT(indexTuple);
 		if (index->indislossy)
 		{
 			lossy = true;
+			ReleaseSysCache(indexTuple);
 			break;
 		}
+		ReleaseSysCache(indexTuple);
 	}
 
 	/*
@@ -904,18 +906,19 @@ fix_indxqual_references(List *indexquals, IndexPath *index_path)
 		Form_pg_index index;
 
 		/* Get the relam from the index's pg_class entry */
-		indexTuple = SearchSysCacheTuple(RELOID,
-										 ObjectIdGetDatum(indexid),
-										 0, 0, 0);
+		indexTuple = SearchSysCache(RELOID,
+									ObjectIdGetDatum(indexid),
+									0, 0, 0);
 		if (!HeapTupleIsValid(indexTuple))
 			elog(ERROR, "fix_indxqual_references: index %u not found in pg_class",
 				 indexid);
 		relam = ((Form_pg_class) GETSTRUCT(indexTuple))->relam;
+		ReleaseSysCache(indexTuple);
 
 		/* Need the index's pg_index entry for other stuff */
-		indexTuple = SearchSysCacheTuple(INDEXRELID,
-										 ObjectIdGetDatum(indexid),
-										 0, 0, 0);
+		indexTuple = SearchSysCache(INDEXRELID,
+									ObjectIdGetDatum(indexid),
+									0, 0, 0);
 		if (!HeapTupleIsValid(indexTuple))
 			elog(ERROR, "fix_indxqual_references: index %u not found in pg_index",
 				 indexid);
@@ -927,6 +930,8 @@ fix_indxqual_references(List *indexquals, IndexPath *index_path)
 												   relam,
 												   index));
 
+		ReleaseSysCache(indexTuple);
+
 		indexids = lnext(indexids);
 	}
 	return fixed_quals;
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index acee58b7f07..3bea06e2af6 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/initsplan.c,v 1.51 2000/09/29 18:21:33 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/initsplan.c,v 1.52 2000/11/16 22:30:25 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -31,6 +31,7 @@
 #include "parser/parse_oper.h"
 #include "parser/parse_type.h"
 #include "utils/lsyscache.h"
+#include "utils/syscache.h"
 
 
 static void mark_baserels_for_outer_join(Query *root, Relids rels,
@@ -636,6 +637,8 @@ process_implied_equality(Query *root, Node *item1, Node *item2,
 									 BOOLOID); /* operator result type */
 	clause->args = makeList2(item1, item2);
 
+	ReleaseSysCache(eq_operator);
+
 	/*
 	 * Note: we mark the qual "pushed down" to ensure that it can never be
 	 * taken for an original JOIN/ON clause.  We also claim it is an outer-
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
index 296164acb89..c36e7fe7b81 100644
--- a/src/backend/optimizer/plan/subselect.c
+++ b/src/backend/optimizer/plan/subselect.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.44 2000/10/26 21:36:09 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.45 2000/11/16 22:30:25 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -23,7 +23,7 @@
 #include "optimizer/subselect.h"
 #include "parser/parse_expr.h"
 #include "parser/parse_oper.h"
-#include "utils/lsyscache.h"
+#include "utils/syscache.h"
 
 
 Index		PlannerQueryLevel;	/* level of current query */
@@ -271,8 +271,11 @@ make_subplan(SubLink *slink)
 			pfree(var);			/* var is only needed for new_param */
 
 			Assert(IsA(oper, Oper));
-			tup = get_operator_tuple(oper->opno);
-			Assert(HeapTupleIsValid(tup));
+			tup = SearchSysCache(OPEROID,
+								 ObjectIdGetDatum(oper->opno),
+								 0, 0, 0);
+			if (! HeapTupleIsValid(tup))
+				elog(ERROR, "cache lookup failed for operator %u", oper->opno);
 			opform = (Form_pg_operator) GETSTRUCT(tup);
 
 			/*
@@ -283,6 +286,8 @@ make_subplan(SubLink *slink)
 								exprType(lefthand), opform->oprleft);
 			right = make_operand("", (Node *) prm,
 								 prm->paramtype, opform->oprright);
+			ReleaseSysCache(tup);
+
 			newoper = lappend(newoper,
 							  make_opclause(oper,
 											(Var *) left,
@@ -401,15 +406,14 @@ make_subplan(SubLink *slink)
 			Node	   *left,
 					   *right;
 
-			/*
-			 * XXX really ought to fill in constlen and constbyval
-			 * correctly, but right now ExecEvalExpr won't look at them...
-			 */
-			con = makeConst(te->resdom->restype, 0, 0, true, 0, 0, 0);
+			con = makeNullConst(te->resdom->restype);
 
 			Assert(IsA(oper, Oper));
-			tup = get_operator_tuple(oper->opno);
-			Assert(HeapTupleIsValid(tup));
+			tup = SearchSysCache(OPEROID,
+								 ObjectIdGetDatum(oper->opno),
+								 0, 0, 0);
+			if (! HeapTupleIsValid(tup))
+				elog(ERROR, "cache lookup failed for operator %u", oper->opno);
 			opform = (Form_pg_operator) GETSTRUCT(tup);
 
 			/*
@@ -420,6 +424,8 @@ make_subplan(SubLink *slink)
 								exprType(lefthand), opform->oprleft);
 			right = make_operand("", (Node *) con,
 								 con->consttype, opform->oprright);
+			ReleaseSysCache(tup);
+
 			newoper = lappend(newoper,
 							  make_opclause(oper,
 											(Var *) left,