Attached patch gets rid of the global timezone in the following steps:

* Changes the APIs to the timezone functions to take a pg_tz pointer as
an argument, representing the timezone to use for the selected
operation.

* Adds a global_timezone variable that represents the current timezone
in the backend as set by SET TIMEZONE (or guc, or env, etc).

* Implements a hash-table cache of loaded tables, so we don't have to
read and parse the TZ file everytime we change a timezone. While not
necesasry now (we don't change timezones very often), I beleive this
will be necessary (or at least good) when "multiple timezones in the
same query" is eventually implemented. And code-wise, this was the time
to do it.


There are no user-visible changes at this time. Implementing the
"multiple zones in one query" is a later step...

This also gets rid of some of the cruft needed to "back out a timezone
change", since we previously couldn't check a timezone unless it was
activated first.

Passes regression tests on win32, linux (slackware 10) and solaris x86.

Magnus Hagander

3 files changed, 8 insertions, 7 deletions

diff --git a/src/backend/utils/adt/datetime.c b/src/backend/utils/adt/datetime.c
index 47dc28d132..0ac92c304b 100644
--- a/src/backend/utils/adt/datetime.c
+++ b/src/backend/utils/adt/datetime.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.137 2005/01/11 18:33:45 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.138 2005/04/19 03:13:59 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1634,7 +1634,8 @@ DetermineLocalTimeZone(struct pg_tm * tm)
 	res = pg_next_dst_boundary(&prevtime,
 							   &before_gmtoff, &before_isdst,
 							   &boundary,
-							   &after_gmtoff, &after_isdst);
+							   &after_gmtoff, &after_isdst,
+		                       global_timezone);
 	if (res < 0)
 		goto overflow;			/* failure? */
 
diff --git a/src/backend/utils/adt/nabstime.c b/src/backend/utils/adt/nabstime.c
index 4e2069f5fb..631c700c5a 100644
--- a/src/backend/utils/adt/nabstime.c
+++ b/src/backend/utils/adt/nabstime.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/nabstime.c,v 1.127 2004/12/31 22:01:22 pgsql Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/nabstime.c,v 1.128 2005/04/19 03:13:59 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -192,7 +192,7 @@ abstime2tm(AbsoluteTime _time, int *tzp, struct pg_tm * tm, char **tzn)
 		time -= CTimeZone;
 
 	if ((!HasCTZSet) && (tzp != NULL))
-		tx = pg_localtime(&time);
+		tx = pg_localtime(&time,global_timezone);
 	else
 		tx = pg_gmtime(&time);
 
@@ -1677,7 +1677,7 @@ timeofday(PG_FUNCTION_ARGS)
 	gettimeofday(&tp, &tpz);
 	tt = (pg_time_t) tp.tv_sec;
 	pg_strftime(templ, sizeof(templ), "%a %b %d %H:%M:%S.%%06d %Y %Z",
-				pg_localtime(&tt));
+				pg_localtime(&tt,global_timezone));
 	snprintf(buf, sizeof(buf), templ, tp.tv_usec);
 
 	len = VARHDRSZ + strlen(buf);
diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index 1f82b2fec9..1da473dbfb 100644
--- a/src/backend/utils/adt/timestamp.c
+++ b/src/backend/utils/adt/timestamp.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.118 2005/04/01 14:25:23 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.119 2005/04/19 03:13:59 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1078,7 +1078,7 @@ timestamp2tm(Timestamp dt, int *tzp, struct pg_tm * tm, fsec_t *fsec, char **tzn
 	utime = (pg_time_t) dt;
 	if ((Timestamp) utime == dt)
 	{
-		struct pg_tm *tx = pg_localtime(&utime);
+		struct pg_tm *tx = pg_localtime(&utime, global_timezone);
 
 		tm->tm_year = tx->tm_year + 1900;
 		tm->tm_mon = tx->tm_mon + 1;