| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Ogden <lists(at)darkstatic(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Query much faster with enable_seqscan=0 |
| Date: | 2010-09-21 23:30:32 |
| Message-ID: | 11723.1285111832@sss.pgh.pa.us |
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| Thread: | |
| Lists: | pgsql-performance |
Ogden <lists(at)darkstatic(dot)com> writes:
> SELECT tr.id, tr.sid
> FROM
> test_registration tr,
> INNER JOIN test_registration_result r on (tr.id = r.test_registration_id)
> WHERE.
> tr.test_administration_id='32a22b12-aa21-11df-a606-96551e8f4e4c'::uuid
> GROUP BY tr.id, tr.sid
Seeing that tr.id is a primary key, I think you might be a lot better
off if you avoided the inner join and group by. I think what you really
want here is something like
SELECT tr.id, tr.sid
FROM
test_registration tr
WHERE
tr.test_administration_id='32a22b12-aa21-11df-a606-96551e8f4e4c'::uuid
AND EXISTS(SELECT 1 FROM test_registration_result r
WHERE tr.id = r.test_registration_id)
regards, tom lane
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