Re: CLUSTER, using SHARE UPDATE EXCLUSIVE lock? - Mailing list pgsql-hackers

From Martijn van Oosterhout
Subject Re: CLUSTER, using SHARE UPDATE EXCLUSIVE lock?
Date
Msg-id 20070301184756.GE1705@svana.org
Whole thread Raw
In response to Re: CLUSTER, using SHARE UPDATE EXCLUSIVE lock?  (Jonathan Scher <js@oxado.com>)
Responses Re: CLUSTER, using SHARE UPDATE EXCLUSIVE lock?  (Jonathan Scher <js@oxado.com>)
List pgsql-hackers
On Thu, Mar 01, 2007 at 06:23:37PM +0100, Jonathan Scher wrote:
> >Because when it drops the old copy of the table there had better not be
> >any concurrent readers.

> Then, is it possible to take a share update exclusive lock until the new
> table is ready, then an access exclusive one only in order to switch
> tables? I don't think it's already coded like that...

That's lock upgrading, which opens you up to deadlocks. If another
process grabs a lock after your update exclusive, you're not going to
be able to upgrade it.

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.

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