Re: PITR timeline question

Jim Nasby <jnasby(at)pervasive(dot)com> writes:
> On Aug 3, 2006, at 3:01 PM, Tom Lane wrote:
>> The only way to "roll time backwards" is to replace the data directory
>> with a backup, so if I understand your question correctly, the answer
>> is no.

> Well, specifically I was thinking of...

> Roll PITR forward and start database
> Do a bunch of stuff
> Got more WAL files... start database back in recovery and roll
> forward to end of new WAL files (throwing away everything that was
> done previously).

No, that definitely won't work, since any data pages touched by the
"bunch of stuff" and not by the new WAL files will not have been
reverted to their prior states --- while any pages touched in common
*will* have been overwritten. Net result: inconsistent database.

There's been some speculation about allowing a standby server to execute
purely read-only operations, but it's just speculation so far.

regards, tom lane