Re: Automatic optimization of IN clauses via INNER JOIN

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On Thu, Dec 17, 2009 at 10:23 AM, Thomas Hamilton
<thomashamilton76@xxxxxxxxx> wrote:
> Apparently the latest version of MySQL has solved this problem: http://www.xaprb.com/blog/2006/06/28/why-large-in-clauses-are-problematic/
>
> But I am running PostgreSQL v8.3 and am observing generally that SELECT ... WHERE ... IN (a, b, c, ...) is much slower than SELECT ... INNER JOIN (SELECT a UNION ALL SELECT b UNION ALL SELECT c ...)

That's certainly not MY observation.  It would be interesting to see
what's going on in your case but you'll need to provide more details.

http://wiki.postgresql.org/wiki/Guide_to_reporting_problems

...Robert

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