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04-10-2008, 05:44 AM
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 WAL log archive frequency Hi, Further to my question on PITR, I have now implemented it :-) However, I was wondering about the frequency of archiving the WAL. Does postgresql wait until the current WAL file has reached 16MB before calling the archive_command? The reason why I ask is that last night, after doing the base backup, I noticed that a WAL file had been written to my backup server. This morning, I added a primary key to a table but noticed that nothing was written to the backup server. Should it have been? Is there any method of forcing a WAL segment to be archived at a given frequency irrespective of whether or not it is a full 16MB? Our database changes so infrequently at the moment that I'm worried that these small changes may not be backed up regularly by the PITR system. Thanks, Chris -- Chris Jewell, BSc(Hons), BVSc, MRCVS Dept of Maths and Statistics Fylde College Lancaster University Lancaster Lancs LA1 4YF ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend      |
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04-10-2008, 05:44 AM
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| Re: WAL log archive frequency Chris Jewell <c.jewell@lancaster.ac.uk> writes: > Further to my question on PITR, I have now implemented it :-) However, > I was wondering about the frequency of archiving the WAL. Does > postgresql wait until the current WAL file has reached 16MB before > calling the archive_command? Yes. The assumption is the archive_command may be too stupid to deal with archiving the same file more than once, and/or might have performance issues with doing that, eg, if it's writing to tape or some kind of write-once media. You can do something like saving the newest-by-timestamp file in the xlog directory every minute or whatever via a cron job. This ought to be better integrated though ... regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to majordomo@postgresql.org so that your message can get through to the mailing list cleanly |
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