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, 19 insertions, 17 deletions

diff --git a/src/backend/parser/parse_coerce.c b/src/backend/parser/parse_coerce.c
index f0d3427d17e..131d65cbcd0 100644
--- a/src/backend/parser/parse_coerce.c
+++ b/src/backend/parser/parse_coerce.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_coerce.c,v 2.48 2000/11/09 04:14:32 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_coerce.c,v 2.49 2000/11/16 22:30:27 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -84,6 +84,8 @@ coerce_type(ParseState *pstate, Node *node, Oid inputTypeId,
 			pfree(val);
 		}
 
+		ReleaseSysCache(targetType);
+
 		result = (Node *) newcon;
 	}
 	else if (IS_BINARY_COMPATIBLE(inputTypeId, targetTypeId))
@@ -124,9 +126,8 @@ coerce_type(ParseState *pstate, Node *node, Oid inputTypeId,
 		 * conversion function.
 		 */
 		FuncCall   *n = makeNode(FuncCall);
-		Type		targetType = typeidType(targetTypeId);
 
-		n->funcname = typeTypeName(targetType);
+		n->funcname = typeidTypeName(targetTypeId);
 		n->args = lcons(node, NIL);
 		n->agg_star = false;
 		n->agg_distinct = false;
@@ -136,7 +137,7 @@ coerce_type(ParseState *pstate, Node *node, Oid inputTypeId,
 		/* safety check that we got the right thing */
 		if (exprType(result) != targetTypeId)
 			elog(ERROR, "coerce_type: conversion function %s produced %s",
-				 typeTypeName(targetType),
+				 typeidTypeName(targetTypeId),
 				 typeidTypeName(exprType(result)));
 
 		/*
@@ -233,17 +234,21 @@ can_coerce_type(int nargs, Oid *input_typeids, Oid *func_typeids)
 		MemSet(oid_array, 0, FUNC_MAX_ARGS * sizeof(Oid));
 		oid_array[0] = inputTypeId;
 
-		ftup = SearchSysCacheTuple(PROCNAME,
-						   PointerGetDatum(typeidTypeName(targetTypeId)),
-								   Int32GetDatum(1),
-								   PointerGetDatum(oid_array),
-								   0);
+		ftup = SearchSysCache(PROCNAME,
+							  PointerGetDatum(typeidTypeName(targetTypeId)),
+							  Int32GetDatum(1),
+							  PointerGetDatum(oid_array),
+							  0);
 		if (!HeapTupleIsValid(ftup))
 			return false;
 		/* Make sure the function's result type is as expected, too */
 		pform = (Form_pg_proc) GETSTRUCT(ftup);
 		if (pform->prorettype != targetTypeId)
+		{
+			ReleaseSysCache(ftup);
 			return false;
+		}
+		ReleaseSysCache(ftup);
 	}
 
 	return true;
@@ -272,7 +277,6 @@ coerce_type_typmod(ParseState *pstate, Node *node,
 {
 	char	   *funcname;
 	Oid			oid_array[FUNC_MAX_ARGS];
-	HeapTuple	ftup;
 
 	/*
 	 * We assume that only typmod values greater than 0 indicate a forced
@@ -288,13 +292,11 @@ coerce_type_typmod(ParseState *pstate, Node *node,
 	oid_array[1] = INT4OID;
 
 	/* attempt to find with arguments exactly as specified... */
-	ftup = SearchSysCacheTuple(PROCNAME,
-							   PointerGetDatum(funcname),
-							   Int32GetDatum(2),
-							   PointerGetDatum(oid_array),
-							   0);
-
-	if (HeapTupleIsValid(ftup))
+	if (SearchSysCacheExists(PROCNAME,
+							 PointerGetDatum(funcname),
+							 Int32GetDatum(2),
+							 PointerGetDatum(oid_array),
+							 0))
 	{
 		A_Const    *cons = makeNode(A_Const);
 		FuncCall   *func = makeNode(FuncCall);