Jim C. Nasby wrote: > On Mon, Apr 17, 2006 at 03:00:58PM -0400, Tom Lane wrote: > > I've applied a patch for this. On reflection, the CHECKPOINT during > > pg_start_backup was actually necessary for torn-page safety even without > > full_page_writes off. The reason is that the torn-page risk occurs when > > we write a page from shared memory, not when we modify it in memory. > > Without a CHECKPOINT, a page modified just before pg_start_backup could > > be dumped during the backup and then be saved in a torn state, even > > though no WAL record for it is emitted anytime during the backup > > procedure. So that comment's been wrong all along. > > Are you going to back-patch this? If I understand correctly current > behavior could mean people using PITR may have invalid backups. In the > meantime, perhaps we should send an email to -annouce recommending that > folks issue a CHEKCPOINT; after pg_start_backup and before initiating > the filesystem copy.
We are disabling full_page_writes for 8.1.4, so they should be fine. -- Bruce Momjian http://candle.pha.pa.us EnterpriseDB http://www.enterprisedb.com + If your life is a hard drive, Christ can be your backup. + ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
