Re: Documentation on PITR still scarce

Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:

> I suppose it might be useful to have some kind of "suspended animation"
> behavior where you could bring up a backend and look at the database in
> a strict read-only fashion, not really executing transactions at all,
> just to see what you had. Then you could end the recovery and go to
> normal operations, or allow the recovery to proceed further if you
> decided this wasn't where you wanted to be yet. However that would
> require a great deal of mechanism we haven't got (yet). In particular
> there is no such thing as strict read-only examination of the database.

That would be a great thing to have one day for other reasons aside from the
ability to test out a recovered database. It makes warm standby databases much
more useful.

A warm standby is when you keep a second machine constantly up to date by
applying the archived PITR logs as soon as they come off your server. You're
ready to switch over at the drop of a hat and don't have to go through the
whole recovery process, you just switch the database from recovery mode to
active mode and make it your primary database. But in the until then the
backup hardware languishes, completely useless.

Oracle has had a feature for a long time that you can actually open the
standby database in a strict read-only mode and run queries. This is great for
a data warehouse situation where you want to run long batch jobs against
recent data.

--
greg