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 ...) Why doesn't the optimizer automatically transform IN clauses to INNER JOINs in this fashion? -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
