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Re: Clarification on a Time travel feature

From: "Gokulakannan Somasundaram" <gokul007(at)gmail(dot)com>
To: "Hans-Juergen Schoenig" <postgres(at)cybertec(dot)at>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: Clarification on a Time travel feature
Date: 2007-10-31 11:38:49
Message-ID: 9362e74e0710310438q34a4414bp22c8e09923ce3cbb@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-hackers
No i am referring to time travel within a transaction, not outside.

On 10/31/07, Hans-Juergen Schoenig <postgres(at)cybertec(dot)at> wrote:
>
> hello ...
>
> i guess there is no formal proposal yet but there are some ideas around
> and some major challenges have been discussed already.
> i think simon riggs was planning to work on it in the future.
> the basic idea here is to have the option to create a "snapshot" which
> then stays in the database. the main challenge is that PostgreSQL
> should not keep all version of a row since the snapshot but VACUUM should
> be able to clean out all rows which are not seen by any snapshot or any
> ongoing transaction.
> this should be a quite fancy solution which is quite space efficient.
>
> internally we had the idea of tweaking VACUUM a little:
>
> VACUUM BEFORE timestamp;
> and ...
> SET current_snapshot TO '2007-10-10 ...';
>
> this would allow a queries to use any snapshot after the timestamp defined
> by VACUUM (if data is around).
> the downside here: you might potentially eat up more space.
> flashback data should be read only, of course.
>
> best regards,
>
> hans
>
>
>
> On Oct 31, 2007, at 11:31 AM, Gokulakannan Somasundaram wrote:
>
> Hi,
>    I went through the mailing list and couldn't get answer to the
> question.
>
> a) Is there a proposal in place for going back in time within a
> transaction?
>
>
>
> --
> Thanks,
> Gokul.
> CertoSQL Project,
> Allied Solution Groups.
> (www.alliedgroups.com)
>
>
>
>
> --
> Cybertec Schönig & Schönig GmbH
> Gröhrmühlgasse 26, 2700 Wiener Neustadt
> Tel: +43/1/205 10 35 / 340
> www.postgresql.at, www.cybertec.at
>
>
>


-- 
Thanks,
Gokul.
CertoSQL Project,
Allied Solution Groups.
(www.alliedgroups.com)

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Subject: Re: Clarification on a Time travel feature
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Subject: Re: Clarification on a Time travel feature

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