Add a "provariadic" column to pg_proc to eliminate the remarkably expensive

need to deconstruct proargmodes for each pg_proc entry inspected by
FuncnameGetCandidates().  Fixes function lookup performance regression
caused by yesterday's variadic-functions patch.

In passing, make pg_proc.probin be NULL, rather than a dummy value '-',
in cases where it is not actually used for the particular type of function.
This should buy back some of the space cost of the extra column.

1 files changed, 29 insertions, 27 deletions

diff --git a/src/backend/commands/functioncmds.c b/src/backend/commands/functioncmds.c
index cb249d9c7d1..d03de8bff17 100644
--- a/src/backend/commands/functioncmds.c
+++ b/src/backend/commands/functioncmds.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/functioncmds.c,v 1.96 2008/07/16 01:30:22 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/functioncmds.c,v 1.97 2008/07/16 16:55:23 tgl Exp $
  *
  * DESCRIPTION
  *	  These routines take the parse tree and pick out the
@@ -590,7 +590,8 @@ compute_attributes_with_style(List *parameters, bool *isStrict_p, char *volatili
  *	   AS <object reference, or sql code>
  */
 static void
-interpret_AS_clause(Oid languageOid, const char *languageName, List *as,
+interpret_AS_clause(Oid languageOid, const char *languageName,
+					char *funcname, List *as,
 					char **prosrc_str_p, char **probin_str_p)
 {
 	Assert(as != NIL);
@@ -599,25 +600,47 @@ interpret_AS_clause(Oid languageOid, const char *languageName, List *as,
 	{
 		/*
 		 * For "C" language, store the file name in probin and, when given,
-		 * the link symbol name in prosrc.
+		 * the link symbol name in prosrc.  If link symbol is omitted,
+		 * substitute procedure name.  We also allow link symbol to be
+		 * specified as "-", since that was the habit in PG versions before
+		 * 8.4, and there might be dump files out there that don't translate
+		 * that back to "omitted".
 		 */
 		*probin_str_p = strVal(linitial(as));
 		if (list_length(as) == 1)
-			*prosrc_str_p = "-";
+			*prosrc_str_p = funcname;
 		else
+		{
 			*prosrc_str_p = strVal(lsecond(as));
+			if (strcmp(*prosrc_str_p, "-") == 0)
+				*prosrc_str_p = funcname;
+		}
 	}
 	else
 	{
 		/* Everything else wants the given string in prosrc. */
 		*prosrc_str_p = strVal(linitial(as));
-		*probin_str_p = "-";
+		*probin_str_p = NULL;
 
 		if (list_length(as) != 1)
 			ereport(ERROR,
 					(errcode(ERRCODE_INVALID_FUNCTION_DEFINITION),
 					 errmsg("only one AS item needed for language \"%s\"",
 							languageName)));
+
+		if (languageOid == INTERNALlanguageId)
+		{
+			/*
+			 * In PostgreSQL versions before 6.5, the SQL name of the created
+			 * function could not be different from the internal name, and
+			 * "prosrc" wasn't used.  So there is code out there that does
+			 * CREATE FUNCTION xyz AS '' LANGUAGE internal. To preserve some
+			 * modicum of backwards compatibility, accept an empty "prosrc"
+			 * value as meaning the supplied SQL function name.
+			 */
+			if (strlen(*prosrc_str_p) == 0)
+				*prosrc_str_p = funcname;
+		}
 	}
 }
 
@@ -759,30 +782,9 @@ CreateFunction(CreateFunctionStmt *stmt)
 
 	compute_attributes_with_style(stmt->withClause, &isStrict, &volatility);
 
-	interpret_AS_clause(languageOid, languageName, as_clause,
+	interpret_AS_clause(languageOid, languageName, funcname, as_clause,
 						&prosrc_str, &probin_str);
 
-	if (languageOid == INTERNALlanguageId)
-	{
-		/*
-		 * In PostgreSQL versions before 6.5, the SQL name of the created
-		 * function could not be different from the internal name, and
-		 * "prosrc" wasn't used.  So there is code out there that does CREATE
-		 * FUNCTION xyz AS '' LANGUAGE internal. To preserve some modicum of
-		 * backwards compatibility, accept an empty "prosrc" value as meaning
-		 * the supplied SQL function name.
-		 */
-		if (strlen(prosrc_str) == 0)
-			prosrc_str = funcname;
-	}
-
-	if (languageOid == ClanguageId)
-	{
-		/* If link symbol is specified as "-", substitute procedure name */
-		if (strcmp(prosrc_str, "-") == 0)
-			prosrc_str = funcname;
-	}
-
 	/*
 	 * Set default values for COST and ROWS depending on other parameters;
 	 * reject ROWS if it's not returnsSet.  NB: pg_dump knows these default