Re: WAL recovery, stop and resume recovery? - Mailing list pgsql-admin

From David Wall
Subject Re: WAL recovery, stop and resume recovery?
Date
Msg-id 4787DAB4.9020402@computer.org
Whole thread Raw
In response to Re: WAL recovery, stop and resume recovery?  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-admin
> No.  Once you've done any transactions in the backup DB, its transaction
> history has diverged from the master and you can't resume tracking the
> master.  It shouldn't even let you try --- what shenanigans did you pull
> to force it back into recovery mode?
>
Well, I didn't think it was shenanigans, I just stopped the database
once it completed the first recovery, ran a few queries, then
re-installed the recovery.conf and started it back up like I initially
did.  I figured this could be an issue, but since I hadn't issued any
changes, I had hoped it might work.
> There's some work being done on allowing read-only queries against an
> in-recovery database, which I think would satisfy your desire to see if
> the backup were sane or not.  But I wouldn't bet money on that getting
> into the system anytime soon.  It's definitely not something you can
> cobble up from spare parts.
>
Fair enough.  It's probably not a big deal as I'm doing this only
because we're new to using WAL copying for a warm standby, and of course
we're testing to see that rows inserted, removed, updated, tables added
and dropped, indexes added and dropped, etc. are all making it through.
It appears that this works like a charm!

Is there a way to know how many WAL files I should keep around to ensure
I can recover back to a valid primary checkpoint without having to redo
the entire backup process on the primary in 8.2, or do I just have to
wait for 8.3 and %r option for recovery?

Thanks,
David


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