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, 13 insertions, 17 deletions

diff --git a/src/backend/commands/proclang.c b/src/backend/commands/proclang.c
index ec8aec7005f..5d4d3f09bf7 100644
--- a/src/backend/commands/proclang.c
+++ b/src/backend/commands/proclang.c
@@ -48,7 +48,6 @@ void
 CreateProceduralLanguage(CreatePLangStmt *stmt)
 {
 	char		languageName[NAMEDATALEN];
-	HeapTuple	langTup;
 	HeapTuple	procTup;
 
 	Oid			typev[FUNC_MAX_ARGS];
@@ -77,10 +76,9 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 	 */
 	case_translate_language_name(stmt->plname, languageName);
 
-	langTup = SearchSysCacheTuple(LANGNAME,
-								  PointerGetDatum(languageName),
-								  0, 0, 0);
-	if (HeapTupleIsValid(langTup))
+	if (SearchSysCacheExists(LANGNAME,
+							 PointerGetDatum(languageName),
+							 0, 0, 0))
 		elog(ERROR, "Language %s already exists", languageName);
 
 	/* ----------------
@@ -89,21 +87,17 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 	 * ----------------
 	 */
 	memset(typev, 0, sizeof(typev));
-	procTup = SearchSysCacheTuple(PROCNAME,
-								  PointerGetDatum(stmt->plhandler),
-								  Int32GetDatum(0),
-								  PointerGetDatum(typev),
-								  0);
+	procTup = SearchSysCache(PROCNAME,
+							 PointerGetDatum(stmt->plhandler),
+							 Int32GetDatum(0),
+							 PointerGetDatum(typev),
+							 0);
 	if (!HeapTupleIsValid(procTup))
-	{
 		elog(ERROR, "PL handler function %s() doesn't exist",
 			 stmt->plhandler);
-	}
 	if (((Form_pg_proc) GETSTRUCT(procTup))->prorettype != InvalidOid)
-	{
 		elog(ERROR, "PL handler function %s() isn't of return type Opaque",
 			 stmt->plhandler);
-	}
 
 	/* ----------------
 	 * Insert the new language into pg_language
@@ -123,6 +117,8 @@ CreateProceduralLanguage(CreatePLangStmt *stmt)
 	values[i++] = DirectFunctionCall1(textin,
 									  CStringGetDatum(stmt->plcompiler));
 
+	ReleaseSysCache(procTup);
+
 	rel = heap_openr(LanguageRelationName, RowExclusiveLock);
 
 	tupDesc = rel->rd_att;
@@ -173,9 +169,9 @@ DropProceduralLanguage(DropPLangStmt *stmt)
 
 	rel = heap_openr(LanguageRelationName, RowExclusiveLock);
 
-	langTup = SearchSysCacheTupleCopy(LANGNAME,
-									  PointerGetDatum(languageName),
-									  0, 0, 0);
+	langTup = SearchSysCacheCopy(LANGNAME,
+								 PointerGetDatum(languageName),
+								 0, 0, 0);
 	if (!HeapTupleIsValid(langTup))
 		elog(ERROR, "Language %s doesn't exist", languageName);