From: Richard Huxton <dev@archonet.com>
To: Simon Riggs <simon@2ndquadrant.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@postgresql.org
Subject: Re: Point in Time Recovery
Date: Tue, 06 Jul 2004 20:00:51 +0100
Message-ID: <40EAF6E3.9090508@archonet.com> (raw)
In-Reply-To: <1089069104.17493.132.camel@stromboli>
References: <1089060299.17493.58.camel@stromboli>
<4263.1089064016@sss.pgh.pa.us>
<1089069104.17493.132.camel@stromboli>
Simon Riggs wrote:
> On Mon, 2004-07-05 at 22:46, Tom Lane wrote:
>
>>Simon Riggs <simon@2ndquadrant.com> writes:
>>
>>>Should we use a different datatype than time_t for the commit timestamp,
>>>one that offers more fine grained differentiation between checkpoints?
>>
>>Pretty much everybody supports gettimeofday() (time_t and separate
>>integer microseconds); you might as well use that. Note that the actual
>>resolution is not necessarily microseconds, and it'd still not be
>>certain that successive commits have distinct timestamps --- so maybe
>>this refinement would be pointless. You'll still have to design a user
>>interface that allows selection without the assumption of distinct
>>timestamps.
>
>
> Well, I agree, though without the desired-for UI now, I think some finer
> grained mechanism would be good. This means extending the xlog commit
> record by a couple of bytes...OK, lets live a little.
At the risk of irritating people, I'll repeat what I suggested a few
weeks ago...
Add a table: pg_pitr_checkpt (pitr_id SERIAL, pitr_ts timestamptz,
pitr_comment text)
Let the user insert rows in transactions as desired. Let them stop the
restore when a specific (pitr_ts,pitr_comment) gets inserted (or on
pitr_id if they record it).
IMHO time is seldom relevant, event boundaries are.
If you want to add special syntax for this, fine. If not, an INSERT
statement is a convenient way to do this anyway.
--
Richard Huxton
Archonet Ltd
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Cc: dev@archonet.com, simon@2ndquadrant.com, tgl@sss.pgh.pa.us, pgsql-hackers@postgresql.org
Subject: Re: Point in Time Recovery
In-Reply-To: <40EAF6E3.9090508@archonet.com>
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