| From: | Gregory Stark <stark(at)enterprisedb(dot)com> |
|---|---|
| To: | Martijn van Oosterhout <kleptog(at)svana(dot)org> |
| Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Zdenek Kotala <Zdenek(dot)Kotala(at)sun(dot)com>, Greg Stark <greg(dot)stark(at)enterprisedb(dot)com>, Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: [WIP] In-place upgrade |
| Date: | 2008-11-06 01:38:26 |
| Message-ID: | 87iqr1ab1p.fsf@oxford.xeocode.com |
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| Lists: | pgsql-hackers |
Martijn van Oosterhout <kleptog(at)svana(dot)org> writes:
> On Wed, Nov 05, 2008 at 09:41:52PM +0000, Gregory Stark wrote:
>> "Robert Haas" <robertmhaas(at)gmail(dot)com> writes:
>>
>> >> Problem is how to move tuple from page to another and keep indexes in sync.
>> >> One solution is to perform some think like "update" operation on the tuple.
>> >> But you need exclusive lock on the page and pin counter have to be zero. And
>> >> question is where it is safe operation.
>> >
>> > But doesn't this problem go away if you do it in a transaction? You
>> > set xmax on the old tuple, write the new tuple, and add index entries
>> > just as you would for a normal update.
>>
>> But that doesn't actually solve the overflow problem on the old page...
>
> Sure it does. You move just enough tuples that you can convert the page
> without an overflow.
setting the xmax on a tuple doesn't "move" the tuple
--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com
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