Re: IN vs EXISTS equivalence

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От Kevin Grittner
Тема Re: IN vs EXISTS equivalence
Дата
Msg-id 4898130A.EE98.0025.0@wicourts.gov
обсуждение исходный текст
Ответ на Re: IN vs EXISTS equivalence  (Tom Lane <tgl@sss.pgh.pa.us>)
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>>> On Mon, Aug 4, 2008 at  6:48 PM, in message
<15026.1217893692@sss.pgh.pa.us>,
Tom Lane <tgl@sss.pgh.pa.us> wrote: 
> "Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
>> I'm adding some NOT EXISTS examples to the thread for completeness
of
>> what someone might want to address while working on it.  For two
>> queries which can easily be shown (to a human viewer, anyway) to
>> return identical results, I see performance differences of over
five
>> orders of magnitude.
> 
> Could we see EXPLAIN ANALYZE not just EXPLAIN for these?  When
people
> are complaining of bad planner behavior, I don't find bare EXPLAIN
> output to be very convincing.
I'll give it a shot.  I've never had the patience to let the one with
the cost five or six orders of magnitude higher than the others run to
completion, but I've started the lot of 'em.
-Kevin


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