diff --git a/src/bin/psql/tab-complete.in.c b/src/bin/psql/tab-complete.in.c
index f2734f8f273..39bf3024ed4 100644
--- a/src/bin/psql/tab-complete.in.c
+++ b/src/bin/psql/tab-complete.in.c
@@ -1002,7 +1002,7 @@ static const SchemaQuery Query_for_trigger_of_table = {
 
 #define Query_for_list_of_database_vars \
 "SELECT conf FROM ("\
-"       SELECT setdatabase, pg_catalog.split_part(unnest(setconfig),'=',1) conf"\
+"       SELECT setdatabase, pg_catalog.split_part(pg_catalog.unnest(setconfig),'=',1) conf"\
 "         FROM pg_db_role_setting "\
 "       ) s, pg_database d "\
 " WHERE s.setdatabase = d.oid "\