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Re: Subquery WHERE IN or WHERE EXISTS faster? - Mailing list pgsql-performance

From Tom Lane
Subject Re: Subquery WHERE IN or WHERE EXISTS faster?
Date
Msg-id 29009.1214668423@sss.pgh.pa.us
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In response to Subquery WHERE IN or WHERE EXISTS faster?  (Ulrich <ulrich.mierendorff@gmx.net>)
Responses Re: Subquery WHERE IN or WHERE EXISTS faster?
Re: Subquery WHERE IN or WHERE EXISTS faster?
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Ulrich <ulrich.mierendorff@gmx.net> writes:
> People say that [EXISTS is faster]

People who say that are not reliable authorities, at least as far as
Postgres is concerned.  But it is always a bad idea to extrapolate
results on toy tables to large tables --- quite aside from measurement
noise and caching issues, the planner might pick a different plan when
faced with large tables.  Load up a realistic amount of data and then
see what you get.

            regards, tom lane

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