On Wed, Mar 22, 2006 at 10:06:05AM -0500, Tom Lane wrote: > "Jim C. Nasby" <jnasby@xxxxxxxxxxxxx> writes: > >> PITR wants all changes. Without PITR we can optimize certain logging > >> actions. > > > The only change here is that we're creating a new table based on the > > results of a SELECT. If that SELECT doesn't use anything that's > > non-deterministic, then the machine doing the recovery should already > > have all the data it needs, provided that we log the SELECT that was > > used in the CTAS. > > This is based on a fundamental misconception about the way PITR > log-shipping works. We log actions at the physical level (put this > tuple here), not the logical here's-the-statement-we-executed level. > The two approaches cannot mix, because as soon as there's any physical > discrepancy at all, physical-level actions would be incorrectly applied > to the slave database. Oh, so in other words, SELECT * INTO temp FROM table is inherently non-deterministic at the physical level, so the only way to be able to allow PITR to work is to duplicate all the physical changes. Darn. -- Jim C. Nasby, Sr. Engineering Consultant jnasby@xxxxxxxxxxxxx Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
