Make pg_get_statisticsobjdef_expressions return NULL

tvondra · tvondra · commit 8d4b311d2494 · 2021-05-07T14:34:16.000+02:00
The usual behavior for functions in ruleutils.c is to return NULL when the object does not exist. pg_get_statisticsobjdef_expressions raised an error instead, so correct that. Reported-by: Justin Pryzby Discussion: https://postgr.es/m/20210505210947.GA27406%40telsasoft.com
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
@@ -1759,9 +1759,9 @@ pg_get_statisticsobjdef_expressions(PG_FUNCTION_ARGS)
 	statexttup = SearchSysCache1(STATEXTOID, ObjectIdGetDatum(statextid));
 
 	if (!HeapTupleIsValid(statexttup))
-		elog(ERROR, "cache lookup failed for statistics object %u", statextid);
+		PG_RETURN_NULL();
 
-	/* has the statistics expressions? */
+	/* Does the stats object have expressions? */
 	has_exprs = !heap_attisnull(statexttup, Anum_pg_statistic_ext_stxexprs, NULL);
 
 	/* no expressions? we're done */
