Lee Geoff wrote on 1999-03-31 13:45 UTC:
I'm interested in storing date/time data in Ingres databases which are running on Unix servers. We are recording timed events on Unix servers as well as Windows 3.1 and NT PCs. I have had problems with the apparent miss-handling of data when viewed before or after a DST transition. Can anyone point me at words of wisdom or good advice?
Words of advice: Store timestamps always in UTC. Make sure all your machines know UTC reliably. This is usually not a problem under Unix, where UTC is the native time zone on which all kernel time information is based (local times are only a convenience display option provided by application software), and where network protocols such as NTP are commonly used to keep the kernel clock and the official UTC in sync better than 10 ms. The problem are occasionally platforms such as those produced by some hacking firm in Redmond with too much market share, which insist on keeping the hardware clock in local time and derives UTC from this by user configuration. These systems are inherently prone to failure, especially around DST switches (see the annual comp.risks discussion of this every fall). Markus -- Markus G. Kuhn, Computer Laboratory, University of Cambridge, UK Email: mkuhn at acm.org, WWW: <http://www.cl.cam.ac.uk/~mgk25/>