| From: | Bernd Helmle <mailings(at)oopsware(dot)de> |
|---|---|
| To: | David Goodenough <david(dot)goodenough(at)btconnect(dot)com> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: How to speed up Exclusive Locking |
| Date: | 2006-12-05 10:57:39 |
| Message-ID: | 378dea27826636cae6e28ff7ef9cce80@oopsware.de |
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| Lists: | pgsql-general |
On Tue, 5 Dec 2006 10:18:21 +0000, David Goodenough <david(dot)goodenough(at)btconnect(dot)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.
Bernd
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