On Fri, Aug 10, 2007 at 04:59:52PM -0400, Tom Lane wrote: > Karsten Hilbert <Karsten.Hilbert@xxxxxxx> writes: > > On Fri, Aug 10, 2007 at 10:11:29AM +0200, Louis-David Mitterrand wrote: > >> So if I understand correctly, a timestamp_tz is ... > > > ... stored as UTC in the backend > > > ... sent to clients shifted by whatever timezone was > > requested by the client by one of several mechanisms: > > > - "set timezone to ..." used by the client > > - "select ... at time zone ..." used by the client > > - the server timezone if neither of the above is used > > The other point to be clear on is that the "shifting" is done according > to whatever timezone rule files the server currently has. Since > politicians keep changing daylight-savings rules, the same UTC date/time > might be displayed differently after an update of the relevant rule > file. (I am located in Paris, GMT+2, using debian unstable) When using "date" here is the output on the server where the postgresql upgrade (or more likely that's server's subsequent misconfiguration) changed our timestamps: uruk:~# date Sat Aug 11 10:50:46 CEST 2007 uruk:~# date --utc Sat Aug 11 08:50:49 UTC 2007 uruk:~# and: uruk:~# tzconfig Your current time zone is set to Europe/Paris But, I found something fishy that particular server: uruk:~# hwclock Sat 11 Aug 2007 10:47:36 AM CEST -0.630123 seconds uruk:~# hwclock --utc Sat 11 Aug 2007 12:47:39 PM CEST -0.600430 seconds Whereas on my other servers "hwclock --utc" displays the same time (is that normal?): zenon:~# hwclock Sat 11 Aug 2007 10:50:21 AM CEST -0.015345 seconds zenon:~# hwclock --utc Sat 11 Aug 2007 10:50:24 AM CEST -0.000235 seconds Is postgres using the same time reference as "hwclock" or "date" ? Thanks, ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org/