ido-pgsql: Use timestamp without time zone in from_unixtime and to_ti…

…mestamp functions

refs #13221

lib/db_ido_pgsql/schema/pgsql.sql

@@ -10,12 +10,14 @@
 -- Functions
 --
 
-CREATE OR REPLACE FUNCTION from_unixtime(bigint) RETURNS timestamp with time zone AS '
-         SELECT to_timestamp($1) AS result
-' LANGUAGE sql;
-
-CREATE OR REPLACE FUNCTION unix_timestamp(timestamp with time zone) RETURNS bigint AS '
-        SELECT EXTRACT(EPOCH FROM $1)::bigint AS result;
+DROP FUNCTION IF EXISTS from_unixtime(bigint);
+CREATE FUNCTION from_unixtime(bigint) RETURNS timestamp AS $$
+  SELECT to_timestamp($1) AT TIME ZONE 'UTC' AS result
+$$ LANGUAGE sql;
+
+DROP FUNCTION IF EXISTS unix_timestamp(timestamp WITH TIME ZONE);
+CREATE OR REPLACE FUNCTION unix_timestamp(timestamp) RETURNS bigint AS '
+  SELECT CAST(EXTRACT(EPOCH FROM $1) AS bigint) AS result;
 ' LANGUAGE sql;