On 3/24/2010 5:58 PM, [email protected] wrote:
> We suffered a deadlock at one point today and I’m looking for some
> advice on how to prevent it from happening again. In the postgres log I
> found the following:
One of the tables seems to be sl_event. What is the other one?
Jan
>
>
>
> ERROR: deadlock detected
>
> DETAIL: Process 20230 waits for ExclusiveLock on relation 31152 of
> database 26523; blocked by process 27297.
>
> Process 27297 waits for AccessExclusiveLock on relation 31205 of
> database 26523; blocked by process 20230.
>
> Process 20230: select "_payments_cluster".ddlScript_prepare(1, -1);
>
> Process 27297: select "_payments_cluster".cleanupEvent('10
> minutes'::interval, 'false'::boolean);
>
> HINT: See server log for query details.
>
> CONTEXT: SQL statement "LOCK TABLE _payments_cluster.sl_event IN
> EXCLUSIVE MODE; INSERT INTO _payments_cluster.sl_event (ev_origin,
> ev_seqno, ev_timestamp, ev_snapshot, ev_type, ev_data1, ev_data2,
> ev_data3, ev_data4, ev_data5, ev_data6, ev_data7, ev_data8) VALUES ('1',
> nextval('_payments_cluster.sl_event_seq'), now(),
> "pg_catalog".txid_current_snapshot(), $1, $2, $3, $4, $5, $6, $7, $8,
> $9); SELECT currval('_payments_cluster.sl_event_seq');"
>
> SQL statement "SELECT
> "_payments_cluster".createEvent('_payments_cluster', 'SYNC', NULL)"
>
> PL/pgSQL function "ddlscript_prepare" line 29 at PERFORM
>
> STATEMENT: select "_payments_cluster".ddlScript_prepare(1, -1);
>
>
>
> So it looks to me like the issue was caused by a ddl script running at
> the same time as a slony cleanupEvent command. Our system requires some
> dynamic changes to our db structure (in the form of new partitions and
> things like that) these ddl scripts could run at any time. So, how can I
> best manage this around the cleanupEvents?
>
>
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