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, 40 insertions, 42 deletions

diff --git a/src/backend/catalog/pg_aggregate.c b/src/backend/catalog/pg_aggregate.c
index e3fa7c5535b..9c9d54c8f3e 100644
--- a/src/backend/catalog/pg_aggregate.c
+++ b/src/backend/catalog/pg_aggregate.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_aggregate.c,v 1.35 2000/07/17 03:04:43 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/pg_aggregate.c,v 1.36 2000/11/16 22:30:17 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -82,15 +82,10 @@ AggregateCreate(char *aggName,
 	 * specified as 'ANY' for a data-independent transition function,
 	 * such as COUNT(*).
 	 */
-	tup = SearchSysCacheTuple(TYPENAME,
+	basetype = GetSysCacheOid(TYPENAME,
 							  PointerGetDatum(aggbasetypeName),
 							  0, 0, 0);
-	if (HeapTupleIsValid(tup))
-	{
-		basetype = tup->t_data->t_oid;
-		Assert(OidIsValid(basetype));
-	}
-	else
+	if (!OidIsValid(basetype))
 	{
 		if (strcasecmp(aggbasetypeName, "ANY") != 0)
 			elog(ERROR, "AggregateCreate: Type '%s' undefined",
@@ -99,24 +94,21 @@ AggregateCreate(char *aggName,
 	}
 
 	/* make sure there is no existing agg of same name and base type */
-	tup = SearchSysCacheTuple(AGGNAME,
-							  PointerGetDatum(aggName),
-							  ObjectIdGetDatum(basetype),
-							  0, 0);
-	if (HeapTupleIsValid(tup))
+	if (SearchSysCacheExists(AGGNAME,
+							 PointerGetDatum(aggName),
+							 ObjectIdGetDatum(basetype),
+							 0, 0))
 		elog(ERROR,
 			 "AggregateCreate: aggregate '%s' with base type '%s' already exists",
 			 aggName, aggbasetypeName);
 
 	/* handle transtype */
-	tup = SearchSysCacheTuple(TYPENAME,
-							  PointerGetDatum(aggtranstypeName),
-							  0, 0, 0);
-	if (!HeapTupleIsValid(tup))
+	transtype = GetSysCacheOid(TYPENAME,
+							   PointerGetDatum(aggtranstypeName),
+							   0, 0, 0);
+	if (!OidIsValid(transtype))
 		elog(ERROR, "AggregateCreate: Type '%s' undefined",
 			 aggtranstypeName);
-	transtype = tup->t_data->t_oid;
-	Assert(OidIsValid(transtype));
 
 	/* handle transfn */
 	fnArgs[0] = transtype;
@@ -129,48 +121,50 @@ AggregateCreate(char *aggName,
 	{
 		nargs = 1;
 	}
-	tup = SearchSysCacheTuple(PROCNAME,
-							  PointerGetDatum(aggtransfnName),
-							  Int32GetDatum(nargs),
-							  PointerGetDatum(fnArgs),
-							  0);
+	tup = SearchSysCache(PROCNAME,
+						 PointerGetDatum(aggtransfnName),
+						 Int32GetDatum(nargs),
+						 PointerGetDatum(fnArgs),
+						 0);
 	if (!HeapTupleIsValid(tup))
 		func_error("AggregateCreate", aggtransfnName, nargs, fnArgs, NULL);
 	transfn = tup->t_data->t_oid;
+	Assert(OidIsValid(transfn));
 	proc = (Form_pg_proc) GETSTRUCT(tup);
 	if (proc->prorettype != transtype)
 		elog(ERROR, "AggregateCreate: return type of '%s' is not '%s'",
 			 aggtransfnName, aggtranstypeName);
-	Assert(OidIsValid(transfn));
 	/*
 	 * If the transfn is strict and the initval is NULL, make sure
 	 * input type and transtype are the same (or at least binary-
 	 * compatible), so that it's OK to use the first input value
 	 * as the initial transValue.
 	 */
-	if (((Form_pg_proc) GETSTRUCT(tup))->proisstrict && agginitval == NULL)
+	if (proc->proisstrict && agginitval == NULL)
 	{
 		if (basetype != transtype &&
 			! IS_BINARY_COMPATIBLE(basetype, transtype))
 			elog(ERROR, "AggregateCreate: must not omit initval when transfn is strict and transtype is not compatible with input type");
 	}
+	ReleaseSysCache(tup);
 
 	/* handle finalfn, if supplied */
 	if (aggfinalfnName)
 	{
 		fnArgs[0] = transtype;
 		fnArgs[1] = 0;
-		tup = SearchSysCacheTuple(PROCNAME,
-								  PointerGetDatum(aggfinalfnName),
-								  Int32GetDatum(1),
-								  PointerGetDatum(fnArgs),
-								  0);
+		tup = SearchSysCache(PROCNAME,
+							 PointerGetDatum(aggfinalfnName),
+							 Int32GetDatum(1),
+							 PointerGetDatum(fnArgs),
+							 0);
 		if (!HeapTupleIsValid(tup))
 			func_error("AggregateCreate", aggfinalfnName, 1, fnArgs, NULL);
 		finalfn = tup->t_data->t_oid;
+		Assert(OidIsValid(finalfn));
 		proc = (Form_pg_proc) GETSTRUCT(tup);
 		finaltype = proc->prorettype;
-		Assert(OidIsValid(finalfn));
+		ReleaseSysCache(tup);
 	}
 	else
 	{
@@ -237,10 +231,10 @@ AggNameGetInitVal(char *aggName, Oid basetype, bool *isNull)
 	Assert(PointerIsValid(aggName));
 	Assert(PointerIsValid(isNull));
 
-	tup = SearchSysCacheTuple(AGGNAME,
-							  PointerGetDatum(aggName),
-							  ObjectIdGetDatum(basetype),
-							  0, 0);
+	tup = SearchSysCache(AGGNAME,
+						 PointerGetDatum(aggName),
+						 ObjectIdGetDatum(basetype),
+						 0, 0);
 	if (!HeapTupleIsValid(tup))
 		elog(ERROR, "AggNameGetInitVal: cache lookup failed for aggregate '%s'",
 			 aggName);
@@ -254,20 +248,24 @@ AggNameGetInitVal(char *aggName, Oid basetype, bool *isNull)
 								  Anum_pg_aggregate_agginitval,
 								  isNull);
 	if (*isNull)
+	{
+		ReleaseSysCache(tup);
 		return (Datum) 0;
+	}
 
 	strInitVal = DatumGetCString(DirectFunctionCall1(textout, textInitVal));
 
-	tup = SearchSysCacheTuple(TYPEOID,
-							  ObjectIdGetDatum(transtype),
-							  0, 0, 0);
+	ReleaseSysCache(tup);
+
+	tup = SearchSysCache(TYPEOID,
+						 ObjectIdGetDatum(transtype),
+						 0, 0, 0);
 	if (!HeapTupleIsValid(tup))
-	{
-		pfree(strInitVal);
 		elog(ERROR, "AggNameGetInitVal: cache lookup failed on aggregate transition function return type %u", transtype);
-	}
+
 	typinput = ((Form_pg_type) GETSTRUCT(tup))->typinput;
 	typelem = ((Form_pg_type) GETSTRUCT(tup))->typelem;
+	ReleaseSysCache(tup);
 
 	initVal = OidFunctionCall3(typinput,
 							   CStringGetDatum(strInitVal),