informix and xntpd
edem asked whether setting the clock backwards with xntpd on Informix 7.31FC4 on HP-UX 11.0 causes problems. Rob Wilson recalled reinitializing servers after Y2K clock changes and urged caution. Art S. Kagel said internal timestamps are sequential integers, but CURRENT and log times may lag unless USEOSTIME is set. martyn.ayshford had moved clocks often without trouble but advised stopping the engine first.
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I want to set time client on database server ( Informix 7.31FC4 , HP-UX 11.0 ). Is there any problem with informix and setting clock backwards ? Adam
I remember that when doing y2k testing we had to reinitialize servers because we changed the clock while they were running. Don't know if it was just because of the year changes or what but I would be very wary of it. edem (sztuka@wsisiz.edu.pl) wrote: : I want to set time client on database server ( Informix 7.31FC4 , HP-UX : 11.0 ). Is there any problem with informix and setting clock backwards ? : Adam -- Rob Wilson rwilson@ntsource.com
For all of its internal timestamps, such as those used to mark updated pages, Informix uses a sequential integer (kind of like a SERIAL column) so the mechanics of Informix should not be affected. If USEOSTIME is not set Informix periodically gets the time from the system for use for CURRENT and message log times, etc and interpolates the current time using a timing loop in a thread (or an alarm of some such). This may not acknowledge the system time adjustment right away so that record timestamps will not only be confusing it will be hard to track backwards from the time adjustment notes in the system logs to find which rows might have been affected. Art S. Kagel edem wrote: > > I want to set time client on database server ( Informix 7.31FC4 , HP-UX > 11.0 ). Is there any problem with informix and setting clock backwards ? > > Adam
We've moved clocks arround a fair bit on informix. Everything works OK. In your place I would shut the engine down, do your stuff then bring it back up. Better safe than sorry, and lets face it you would be very sorry if your IDS breaks. BTW I'd be more worried about other things, like DCE for instance if you use that, moving clocks around can seriously increase you quota of grey hairs. mja In article <384C21F7.BF6B7A8B@bloomberg.net>, kagel@bloomberg.net wrote: > For all of its internal timestamps, such as those used to mark updated > pages, Informix uses a sequential integer (kind of like a SERIAL column) > so the mechanics of Informix should not be affected. If USEOSTIME is not > set Informix periodically gets the time from the system for use for > CURRENT and message log times, etc and interpolates the current time using > a timing loop in a thread (or an alarm of some such). This may not > acknowledge the system time adjustment right away so that record > timestamps will not only be confusing it will be hard to track backwards > from the time adjustment notes in the system logs to find which rows might > have been affected. > > Art S. Kagel > > edem wrote: > > > > I want to set time client on database server ( Informix 7.31FC4 , HP-UX > > 11.0 ). Is there any problem with informix and setting clock backwards ? > > > > Adam > Sent via Deja.com http://www.deja.com/ Before you buy.