1 files changed, 64 insertions, 21 deletions

diff --git a/src/backend/utils/adt/datetime.c b/src/backend/utils/adt/datetime.c
index 965c3b4ff06..45ba7cd9063 100644
--- a/src/backend/utils/adt/datetime.c
+++ b/src/backend/utils/adt/datetime.c
@@ -56,8 +56,9 @@ static void AdjustFractDays(double frac, struct pg_tm * tm, fsec_t *fsec,
 				int scale);
 static int DetermineTimeZoneOffsetInternal(struct pg_tm * tm, pg_tz *tzp,
 								pg_time_t *tp);
-static int DetermineTimeZoneAbbrevOffsetInternal(pg_time_t t, const char *abbr,
-									  pg_tz *tzp, int *isdst);
+static bool DetermineTimeZoneAbbrevOffsetInternal(pg_time_t t,
+									  const char *abbr, pg_tz *tzp,
+									  int *offset, int *isdst);
 static pg_tz *FetchDynamicTimeZone(TimeZoneAbbrevTable *tbl, const datetkn *tp);
 
 
@@ -1689,19 +1690,40 @@ overflow:
  * This differs from the behavior of DetermineTimeZoneOffset() in that a
  * standard-time or daylight-time abbreviation forces use of the corresponding
  * GMT offset even when the zone was then in DS or standard time respectively.
+ * (However, that happens only if we can match the given abbreviation to some
+ * abbreviation that appears in the IANA timezone data.  Otherwise, we fall
+ * back to doing DetermineTimeZoneOffset().)
  */
 int
 DetermineTimeZoneAbbrevOffset(struct pg_tm * tm, const char *abbr, pg_tz *tzp)
 {
 	pg_time_t	t;
+	int			zone_offset;
+	int			abbr_offset;
+	int			abbr_isdst;
 
 	/*
 	 * Compute the UTC time we want to probe at.  (In event of overflow, we'll
 	 * probe at the epoch, which is a bit random but probably doesn't matter.)
 	 */
-	(void) DetermineTimeZoneOffsetInternal(tm, tzp, &t);
+	zone_offset = DetermineTimeZoneOffsetInternal(tm, tzp, &t);
 
-	return DetermineTimeZoneAbbrevOffsetInternal(t, abbr, tzp, &tm->tm_isdst);
+	/*
+	 * Try to match the abbreviation to something in the zone definition.
+	 */
+	if (DetermineTimeZoneAbbrevOffsetInternal(t, abbr, tzp,
+											  &abbr_offset, &abbr_isdst))
+	{
+		/* Success, so use the abbrev-specific answers. */
+		tm->tm_isdst = abbr_isdst;
+		return abbr_offset;
+	}
+
+	/*
+	 * No match, so use the answers we already got from
+	 * DetermineTimeZoneOffsetInternal.
+	 */
+	return zone_offset;
 }
 
 
@@ -1715,19 +1737,41 @@ DetermineTimeZoneAbbrevOffsetTS(TimestampTz ts, const char *abbr,
 								pg_tz *tzp, int *isdst)
 {
 	pg_time_t	t = timestamptz_to_time_t(ts);
+	int			zone_offset;
+	int			abbr_offset;
+	int			tz;
+	struct pg_tm tm;
+	fsec_t		fsec;
 
-	return DetermineTimeZoneAbbrevOffsetInternal(t, abbr, tzp, isdst);
+	/*
+	 * If the abbrev matches anything in the zone data, this is pretty easy.
+	 */
+	if (DetermineTimeZoneAbbrevOffsetInternal(t, abbr, tzp,
+											  &abbr_offset, isdst))
+		return abbr_offset;
+
+	/*
+	 * Else, break down the timestamp so we can use DetermineTimeZoneOffset.
+	 */
+	if (timestamp2tm(ts, &tz, &tm, &fsec, NULL, tzp) != 0)
+		ereport(ERROR,
+				(errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
+				 errmsg("timestamp out of range")));
+
+	zone_offset = DetermineTimeZoneOffset(&tm, tzp);
+	*isdst = tm.tm_isdst;
+	return zone_offset;
 }
 
 
 /* DetermineTimeZoneAbbrevOffsetInternal()
  *
  * Workhorse for above two functions: work from a pg_time_t probe instant.
- * DST status is returned into *isdst.
+ * On success, return GMT offset and DST status into *offset and *isdst.
  */
-static int
-DetermineTimeZoneAbbrevOffsetInternal(pg_time_t t, const char *abbr,
-									  pg_tz *tzp, int *isdst)
+static bool
+DetermineTimeZoneAbbrevOffsetInternal(pg_time_t t, const char *abbr, pg_tz *tzp,
+									  int *offset, int *isdst)
 {
 	char		upabbr[TZ_STRLEN_MAX + 1];
 	unsigned char *p;
@@ -1739,18 +1783,17 @@ DetermineTimeZoneAbbrevOffsetInternal(pg_time_t t, const char *abbr,
 		*p = pg_toupper(*p);
 
 	/* Look up the abbrev's meaning at this time in this zone */
-	if (!pg_interpret_timezone_abbrev(upabbr,
-									  &t,
-									  &gmtoff,
-									  isdst,
-									  tzp))
-		ereport(ERROR,
-				(errcode(ERRCODE_CONFIG_FILE_ERROR),
-				 errmsg("time zone abbreviation \"%s\" is not used in time zone \"%s\"",
-						abbr, pg_get_timezone_name(tzp))));
-
-	/* Change sign to agree with DetermineTimeZoneOffset() */
-	return (int) -gmtoff;
+	if (pg_interpret_timezone_abbrev(upabbr,
+									 &t,
+									 &gmtoff,
+									 isdst,
+									 tzp))
+	{
+		/* Change sign to agree with DetermineTimeZoneOffset() */
+		*offset = (int) -gmtoff;
+		return true;
+	}
+	return false;
 }