Hi Jack, I'm expecting less than 10 records in the resulting set. The BlockUnit table contains 337,253 records; the InteractionParts table contains 279,953 records.
It takes currently 8.3 seconds to execute the query as I have it. Erh, this is embarassing but I'm going to need some help re-writing it with EXISTS... Thanks for the help so far, Yves ----- Original Message ----- From: Jack van Zanen To: Chris Cc: YVES SUCAET ; email@example.com Sent: Thursday, September 25, 2008 7:49 PM Subject: Re: [PHP-DB] query optimization If you can answer the other questions that would help as well you can try rewriting using "exist" instead of "in" But without the basic information like number of records expected and explain plan it is very hard to come up with a better solution. Brgds Jack 2008/9/26 Chris <[EMAIL PROTECTED]> Jack van Zanen wrote: Hi If I am not mistaken, the second part of the union contains all rows that are in the first part of the union. just remove the first part. Kind of. The first part is a join, the second isn't. I was going to suggest rewriting the subquery into a single: where ip.blockid in (...) or bu.blockid in (...) however that'll probably be slower, but def. worth a try. -- Postgresql & php tutorials http://www.designmagick.com/ -- J.A. van Zanen