From: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
To: Zdenek Kotala <Zdenek.Kotala@Sun.COM>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: Prototype: In-place upgrade
Date: Fri, 05 Sep 2008 00:15:54 +0300
Message-ID: <48C0500A.8020301@enterprisedb.com> (raw)
In-Reply-To: <48BB10A2.60503@sun.com>
References: <48BB10A2.60503@sun.com>
The patch seems to be missing the new htup.c file.
Zdenek Kotala wrote:
> Attached patch is prototype of in-place upgrade as was presented on
> PGCon this year.
>
> Main idea is to learn postgres to handle different version of page and
> tuple structures.
>
> 1) page - Patch contains new page API and all code access page through
> this API. Functions check page version and return correct data to
> caller. It is mostly complete now. Only ItemId flags need finish.
>
> 2) tuple - HeapTuple structure has been extended with t_ver attribute
> which contains page layout version and direct access to HeapTupleHeader
> is forbidden. It is possible now only through HeapTuple* functions (see
> htup.c). (HeapTupleHeader access still stays in a several functions like
> heap_form_tuple).
>
> This patch version still does not allow to read old database, but it
> shows how it should work. Main disadvantage of this approach is
> performance penalty.
>
> Please, let me know your opinion about this approach.
>
> Future work:
> 1) learn WAL to process different tuple structure version
> 2) tuple conversion to new version and put it into executor
> (ExecStoreTuple)
> 3) multiversion MaxItemSize constant
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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To: pgsql-hackers@postgresql.org
Cc: heikki.linnakangas@enterprisedb.com, Zdenek.Kotala@Sun.COM
Subject: Re: Prototype: In-place upgrade
In-Reply-To: <48C0500A.8020301@enterprisedb.com>
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