Re: [WIP] In-place upgrade

Martijn van Oosterhout <kleptog@svana.org> writes:

> On Wed, Nov 05, 2008 at 09:41:52PM +0000, Gregory Stark wrote:
>> "Robert Haas" <robertmhaas@gmail.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 Ask me about EnterpriseDB's RemoteDBA services!