Re: PITR (was Re: Type of application that use

On Mon, 2003-10-06 at 01:47, Shridhar Daithankar wrote:
> Ron Johnson wrote:
> >>All that we basically need for PITR is to provide management code that
> >>lets old WAL segments get archived off to tape (or wherever) rather than
> >>deleted, plus some kind of control that lets the roll-forward process be
> >>stopped at the desired point-in-time rather than necessarily running to
> >>the end of the available WAL data. This isn't a trivial amount of code,
> >>but there's no great conceptual difficulty either.
> >
> >
> > Hope everybody realizes that the amount of WALs will get very big
> > on active-update systems...
>
> Of course they will be recycled in some point of time or other. And even if

???? Of course they'll get recycled, after you dump them, prior
to the nightly pg_dump.

> postgresql would provide PITR abilities, that would be nearly useless if WAL is
> recycled.. Its a space/time tradeoff issue..

Again, ?????. Typically (i.e., on DBMSs that currently have PITR,
it's possible to do a "pg_dump" on Sunday, and *only* do "WAL dumps"
each subsequent night, and be able to restore the DB to the point
of failure by doing a "pg_restore" and then applying X number of
"WAL dumps" in sequence.

--
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Ron Johnson, Jr. ron(dot)l(dot)johnson(at)cox(dot)net
Jefferson, LA USA

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