Re: How to speed up Exclusive Locking - Mailing list pgsql-general

From David Goodenough
Subject Re: How to speed up Exclusive Locking
Date
Msg-id 200612051143.32089.david.goodenough@btconnect.com
Whole thread Raw
In response to Re: How to speed up Exclusive Locking  (Bernd Helmle <mailings@oopsware.de>)
Responses Re: How to speed up Exclusive Locking  (Richard Huxton <dev@archonet.com>)
List pgsql-general
On Tuesday 05 December 2006 10:57, Bernd Helmle wrote:
> On Tue, 5 Dec 2006 10:18:21 +0000, David Goodenough
> <david.goodenough@btconnect.com> wrote:
>
> [...]
>
> > The first bits of the sync are done without locking the source tables,
> > and I do these until I find less than some suitable threshold of records
> > needing
> > to be updated.  Then I lock the source tables and do the final sync.
> >
> > The statements issued to lock each table is:-
> >  LOCK TABLE table IN EXCLUSIVE MODE; SELECT 1 FROM table;
>
> So why selecting '1' for each row after locking the relation before? I
> don't know HA-JDBC but this looks really useless. Remove the SELECT and use
> the LOCK TABLE command within the transaction which does the sync for you.
I will give it a try.
>
> Bernd
>
> ---------------------------(end of broadcast)---------------------------
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