Re: PITR - recovery to a particular transaction

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: olly(at)lfix(dot)co(dot)uk
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: PITR - recovery to a particular transaction
Date: 2004-08-07 03:22:50
Message-ID: 200408070322.i773MoN02230@candle.pha.pa.us
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When we do a PITR recovery based on xid, does it stop recovery based on
the start of the xid or the commit of the xid? And if you say
recovery_target_inclusive =true, does it recover that xid while not
recoverying other xids that are higher but committed sooner than the
target xid?

---------------------------------------------------------------------------

Oliver Elphick wrote:
> On Wed, 2004-08-04 at 19:16, Tom Lane wrote:
> > Oliver Elphick <olly(at)lfix(dot)co(dot)uk> writes:
> > > How about adding a logging option to put the transaction id on the log
> > > for every statement that modifies the database? Would that be a small
> > > enough change to be allowed into 8.0?
> >
> > I think we could get away with adding transaction ID as one of the
> > available %-items in log_line_prefix. I'm not sure how useful this
> > really is though --- timestamps are probably more useful overall to
> > have in your log.
>
> Why not both?
>
> You seem to be suggesting that using the id is less useful than the
> time, but surely it's going to be easier to say "this disaster happened
> in transaction 123 so lets do a PITR up to 122" than to say "this
> happened at time x so do PITR up to x - 1 second"; the latter might miss
> several tranactions. Have I got the concepts wrong here?
>
> > The direction I was expecting we'd head in is to
> > provide WAL logfile examination tools.
>
> But that's not going to happen for 8.0, so any means of getting the
> transaction id is better than none.
>
> --
> Oliver Elphick olly(at)lfix(dot)co(dot)uk
> Isle of Wight http://www.lfix.co.uk/oliver
> GPG: 1024D/A54310EA 92C8 39E7 280E 3631 3F0E 1EC0 5664 7A2F A543 10EA
> ========================================
> "And not only so, but we glory in tribulations also;
> knowing that tribulation worketh patience; And
> patience, experience; and experience, hope."
> Romans 5:3,4
>
>
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--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
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