| From: | Martijn van Oosterhout <kleptog(at)svana(dot)org> |
|---|---|
| To: | Jonathan Scher <js(at)oxado(dot)com> |
| Cc: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: CLUSTER, using SHARE UPDATE EXCLUSIVE lock? |
| Date: | 2007-03-01 18:47:56 |
| Message-ID: | 20070301184756.GE1705@svana.org |
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| Lists: | 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(at)svana(dot)org> http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.
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