Re: Very slow queries w/ NOT IN preparation (seems like a bug, test case)

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От Richard Huxton
Тема Re: Very slow queries w/ NOT IN preparation (seems like a bug, test case)
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Msg-id 49198827.3050703@archonet.com
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Ответ на Re: Very slow queries w/ NOT IN preparation (seems like a bug, test case)  (Tom Lane <tgl@sss.pgh.pa.us>)
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Tom Lane wrote:
> Richard Huxton <dev@archonet.com> writes:
>> I've never heard of EXPLAIN ANALYSE being *faster* than the actual
>> query, it's usually slower due to all the timing calls. The only thing
>> it doesn't do is actually send the results over the connection to the
>> client. In your case, you're not actually selecting any columns, so that
>> can't be it.
>
> If I'm reading it right the query returns 5000 instances of "1".  So
> there's definitely scope for the client side to pose a performance
> issue.

But 34s for 5000 single values? Surely you'd loads of queries slow, not
just this "not in" query.

--
  Richard Huxton
  Archonet Ltd

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