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Re: planer don't use index. bad plan for where id = x or id in (select ...) - Mailing list pgsql-general

From Tom Lane
Subject Re: planer don't use index. bad plan for where id = x or id in (select ...)
Date
Msg-id 8712.1085588867@sss.pgh.pa.us
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In response to Re: planer don't use index. bad plan for where id = x or id in (select ...)  (Greg Stark <gsstark@mit.edu>)
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Greg Stark <gsstark@mit.edu> writes:
> ... And you can use UNION ALL instead of UNION
> since the IN will eliminate duplicates anyways. This avoids an extra
> sort/uniquify step.

FWIW, CVS tip realizes that it doesn't need two unique-ification steps
in this scenario.  But I agree that UNION ALL is the cleaner way to
write the query.

            regards, tom lane

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