On Thu, Dec 17, 2009 at 6:05 PM, Robert Haas <robertmhaas@xxxxxxxxx> wrote: > 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 > I asked the same question many times, and answer was always the same - there's no point in doing that... well... I've been asked by folks at work, the same thing (for typical engineer, grasping the idea of join can be hard sometimes...). -- GJ -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
