Re: WAL logging of SELECT ... INTO command

[Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>]

"Jim C. Nasby" <jnasby(at)pervasive(dot)com> writes:
>> PITR wants all changes. Without PITR we can optimise 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.

			regards, tom lane