Add support for AT LOCAL

When converting a timestamp to/from with/without time zone, the SQL
Standard specifies an AT LOCAL variant of AT TIME ZONE which uses the
session's time zone.  This includes three system functions able to do
the work in the same way as the existing flavors for AT TIME ZONE,
except that these need to be marked as stable as they depend on the
session's TimeZone GUC.

Bump catalog version.

Author: Vik Fearing
Reviewed-by: Laurenz Albe, Cary Huang, Michael Paquier
Discussion: https://postgr.es/m/8e25dec4-5667-c1a5-6581-167d710c2182@postgresfriends.org

1 files changed, 20 insertions, 0 deletions

diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index 0e50aaec5a5..e172e906142 100644
--- a/src/backend/utils/adt/timestamp.c
+++ b/src/backend/utils/adt/timestamp.c
@@ -5921,3 +5921,23 @@ generate_series_timestamptz_at_zone(PG_FUNCTION_ARGS)
 {
 	return generate_series_timestamptz_internal(fcinfo);
 }
+
+/* timestamp_at_local()
+ * timestamptz_at_local()
+ *
+ * The regression tests do not like two functions with the same proargs and
+ * prosrc but different proname, but the grammar for AT LOCAL needs an
+ * overloaded name to handle both types of timestamp, so we make simple
+ * wrappers for it.
+ */
+Datum
+timestamp_at_local(PG_FUNCTION_ARGS)
+{
+	return timestamp_timestamptz(fcinfo);
+}
+
+Datum
+timestamptz_at_local(PG_FUNCTION_ARGS)
+{
+	return timestamptz_timestamp(fcinfo);
+}