Re: Message queue table..

Craig Ringer wrote:
> Jesper Krogh wrote:
>>
>> Hi.
>>
>> I have this "message queue" table.. currently with 8m+ records.
>> Picking the top priority messages seem to take quite long.. it is just
>> a matter of searching the index.. (just as explain analyze tells me it
>> does).
>>
>> Can anyone digest further optimizations out of this output? (All
>> records have funcid=4)
>
> You mean all records of interest, right, not all records in the table?

Actually all the records.. since all the other virtual queues currently
are empty.

> What indexes do you have in place? What's the schema? Can you post a "\d
> tablename" from psql?
>
>> # explain analyze SELECT job.jobid, job.funcid, job.arg, job.uniqkey,
>> job.insert_time, job.run_after, job.grabbed_until, job.priority,
>> job.coalesce FROM workqueue.job WHERE (job.funcid = 4) AND
>> (job.run_after <= 1208442668) AND (job.grabbed_until <= 1208442668)
>> AND (job.coalesce = 'Efam') ORDER BY funcid, priority ASC LIMIT 1

I found that removing the funcid from the order by made it use a better
index. (priority, run_after, grabbed_until) that probably makes sense
since the funcid doesnt give any value in the index at all.

thanks for leading me back on track.

Jesper

--
Jesper