Re: IN vs EXISTS equivalence - Mailing list pgsql-hackers

From Kevin Grittner
Subject Re: IN vs EXISTS equivalence
Date
Msg-id 4898130A.EE98.0025.0@wicourts.gov
Whole thread Raw
In response to Re: IN vs EXISTS equivalence  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
>>> 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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