Thread: Daylight Saving Time
As you may know, DST in the US has been changed from 2007. On March 11
we begin DST.
I have searched the Postgres site, but there is no reference to
potential issues that may be caused by this. Also, since the Solaris
port built with the Sun Compiler did have an issue with a Horology test
case, maybe the PORTS team have most experience with this issue?
Does anyone know how this would affect the following ports:
Sun GCC
Windows MINGW
Linux GCC
FWIW, here is any interesting site that describes time zones.
http://webexhibits.org/daylightsaving/b.html
On Tue, Jan 30, 2007 at 02:21:21PM -0700, Match.Grun@thomson.com wrote: > As you may know, DST in the US has been changed from 2007. On March 11 > we begin DST. > > I have searched the Postgres site, but there is no reference to > potential issues that may be caused by this. Also, since the Solaris > port built with the Sun Compiler did have an issue with a Horology test > case, maybe the PORTS team have most experience with this issue? I beleive you are safe as long as you are on the latest versoins - you'll need 8.2.1, 8.1.6 or 8.0.10. Bruce - given that the actual change-time is coming up, how about we add this one to the FAQ? If it isn't now, it's bound to become. > Does anyone know how this would affect the following ports: > > Sun GCC > Windows MINGW > Linux GCC All affected the same way. If you're using a < 8.0 version, postgresql uses the operating systems timezone functions, so you'll have to look at the documentation for your OS. //Magnus
Magnus Hagander wrote: > On Tue, Jan 30, 2007 at 02:21:21PM -0700, Match.Grun@thomson.com wrote: > > As you may know, DST in the US has been changed from 2007. On March 11 > > we begin DST. > > > > I have searched the Postgres site, but there is no reference to > > potential issues that may be caused by this. Also, since the Solaris > > port built with the Sun Compiler did have an issue with a Horology test > > case, maybe the PORTS team have most experience with this issue? > > I beleive you are safe as long as you are on the latest versoins - > you'll need 8.2.1, 8.1.6 or 8.0.10. > > Bruce - given that the actual change-time is coming up, how about we add > this one to the FAQ? If it isn't now, it's bound to become. Uh, I can. I can remember three questions. The problem is that there is a lag between me adding it to the FAQ and people actually seeing it. Is it worth a try? -- Bruce Momjian bruce@momjian.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. +
On Tue, Jan 30, 2007 at 05:17:45PM -0500, Bruce Momjian wrote: > Magnus Hagander wrote: > > On Tue, Jan 30, 2007 at 02:21:21PM -0700, Match.Grun@thomson.com wrote: > > > As you may know, DST in the US has been changed from 2007. On March 11 > > > we begin DST. > > > > > > I have searched the Postgres site, but there is no reference to > > > potential issues that may be caused by this. Also, since the Solaris > > > port built with the Sun Compiler did have an issue with a Horology test > > > case, maybe the PORTS team have most experience with this issue? > > > > I beleive you are safe as long as you are on the latest versoins - > > you'll need 8.2.1, 8.1.6 or 8.0.10. > > > > Bruce - given that the actual change-time is coming up, how about we add > > this one to the FAQ? If it isn't now, it's bound to become. > > Uh, I can. I can remember three questions. The problem is that there > is a lag between me adding it to the FAQ and people actually seeing it. > Is it worth a try? I think so. It'll get visible on google searches fairly soon, and we still have over a month :-) So yeah, go for it IMHO. (I assume you're not tlaking about the technical lag of a couple of hours until it shows up on the website) //Magnus
Magnus Hagander wrote:
> On Tue, Jan 30, 2007 at 05:17:45PM -0500, Bruce Momjian wrote:
> > Magnus Hagander wrote:
> > > On Tue, Jan 30, 2007 at 02:21:21PM -0700, Match.Grun@thomson.com wrote:
> > > > As you may know, DST in the US has been changed from 2007. On March 11
> > > > we begin DST.
> > > >
> > > > I have searched the Postgres site, but there is no reference to
> > > > potential issues that may be caused by this. Also, since the Solaris
> > > > port built with the Sun Compiler did have an issue with a Horology test
> > > > case, maybe the PORTS team have most experience with this issue?
> > >
> > > I beleive you are safe as long as you are on the latest versoins -
> > > you'll need 8.2.1, 8.1.6 or 8.0.10.
> > >
> > > Bruce - given that the actual change-time is coming up, how about we add
> > > this one to the FAQ? If it isn't now, it's bound to become.
> >
> > Uh, I can. I can remember three questions. The problem is that there
> > is a lag between me adding it to the FAQ and people actually seeing it.
> > Is it worth a try?
>
> I think so. It'll get visible on google searches fairly soon, and we
> still have over a month :-) So yeah, go for it IMHO.
OK, added FAQ item:
<H3 id="item1.14">1.14) Will PostgreSQL handle recent daylight
saving time changes in various countries?</H3>
<P>PostgreSQL versions prior to 8.0 use the operating system's
timezone database for daylight saving information. All current
versions of PostgreSQL 8.0 and later contain up-to-date timezone
information.</P>
> (I assume you're not tlaking about the technical lag of a couple of
> hours until it shows up on the website)
Right.
--
Bruce Momjian bruce@momjian.us
EnterpriseDB http://www.enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +
See below. ->-----Original Message----- ->From: Magnus Hagander [mailto:magnus@hagander.net] ->Sent: Tuesday, January 30, 2007 3:05 PM ->To: Grun, Match (TH USA) ->Cc: pgsql-ports@postgresql.org; bruce@momjian.us ->Subject: Re: [PORTS] Daylight Saving Time -> ->On Tue, Jan 30, 2007 at 02:21:21PM -0700, ->Match.Grun@thomson.com wrote: ->> As you may know, DST in the US has been changed from 2007. ->On March 11 ->> we begin DST. ->> ->> I have searched the Postgres site, but there is no reference to ->> potential issues that may be caused by this. Also, since ->the Solaris ->> port built with the Sun Compiler did have an issue with a Horology ->> test case, maybe the PORTS team have most experience with ->this issue? -> ->I beleive you are safe as long as you are on the latest ->versoins - you'll need 8.2.1, 8.1.6 or 8.0.10. -> We are using 8.0.3 so will we be affected. ->Bruce - given that the actual change-time is coming up, how ->about we add this one to the FAQ? If it isn't now, it's bound ->to become. -> -> ->> Does anyone know how this would affect the following ports: ->> ->> Sun GCC ->> Windows MINGW ->> Linux GCC -> ->All affected the same way. ->If you're using a < 8.0 version, postgresql uses the ->operating systems timezone functions, so you'll have to look ->at the documentation for your OS. -> So 8.0.3 > 8.0 - Are we affected? Just to confirm: Versions < 8.0 use the OS timezone functions. Versions > 8.0 use PostgreSQL timezone functions. If that is so, then the PostgreSQL timezone functions and/or Files would need to be updated? The reason I ask, is that I know that Java does it own stuff for timezones. Java JVM's need to have timezone files updated by means of a run-time patch - I have already applied this one. Therefore, I assume that PostgreSQL would need to have some similar changes done. Is this correct? I know that there is a timezone directory in PostgreSQL. There is a (text) file: src/timezone/data/northamerica This appears to contain a set of rules when DST starts and ends. Also, in the deployed version, there are a set of (binary) files in: share/timezone/America Apologies for the follwing questions. You will be flooded with these, so I may as well ask them now. 1) What is the process to get from source to binary? 2) What files need to be changed? 3) Do we need to rebuild and update all files (including executables and binaries? 4) Would we need to shutdown server, install new timezone files and restart server? Note, even Sun could not answer all the questions with their java FAQ, which seemed to be pretty good. We are still waiting a response on that one. Match
Bruce Momjian <bruce@momjian.us> writes:
> OK, added FAQ item:
> <H3 id="item1.14">1.14) Will PostgreSQL handle recent daylight
> saving time changes in various countries?</H3>
> <P>PostgreSQL versions prior to 8.0 use the operating system's
> timezone database for daylight saving information. All current
> versions of PostgreSQL 8.0 and later contain up-to-date timezone
> information.</P>
This fails to answer the question, as you already found out. You need
to say *which* versions contain which updates. I believe a useful
answer will include these facts:
2007 USA changes:
8.0.4 and later, all 8.1.x and up
2007 Canada and Western Australia changes:
8.0.10 and later, 8.1.6 and later, all 8.2.x and up
regards, tom lane
Match.Grun@thomson.com wrote: <snip> > Apologies for the follwing questions. You will be flooded with > these, so I may as well ask them now. > > 1) What is the process to get from source to binary? See makefile in the src/timezone directory and zic.c in the same place. > 2) What files need to be changed? There are lot of changes. Most "dangerous" are changes in the hardlinks. There are many of new TZ files hadlinked to e.g. London and some old hardliked file has now own separate file. > 3) Do we need to rebuild and update all files (including > executables and binaries? I think, if you remove all old timezones and copy new version in the correct directory (e.g. /usr/share/pgsql/timezone) it will work. > 4) Would we need to shutdown server, install new timezone > files and restart server? Yes, postgres keep one used timezone file in the memory. > Note, even Sun could not answer all the questions with their > java FAQ, which seemed to be pretty good. We are still > waiting a response on that one. A lot of answers are also on this page, but PG8.0 is not covered. http://www.sun.com/bigadmin/hubs/dst/software/ Zdenek