| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | michael(dot)mattox(at)verideon(dot)com |
| Cc: | SZUCS Gábor <surrano(at)mailbox(dot)hu>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: How to optimize monstrous query, sorts instead of using index |
| Date: | 2003-06-25 16:39:37 |
| Message-ID: | 4031.1056559177@sss.pgh.pa.us |
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| Lists: | pgsql-performance |
"Michael Mattox" <michael(dot)mattox(at)verideon(dot)com> writes:
> It's much slower but I appreciate you taking the time to try. I'm pretty
> new to SQL so I must admin this query is very confusing for me. I'm using
> Java Data Objects (JDO, an O/R mapping framework) but the implementation I'm
> using (Kodo) isn't smart enough to do all the joins efficiently, which is
> why I had to rewrite this query by hand.
It wasn't till I read that :-( that I noticed that you were doing nested
left joins. Fooling with the join order may be your best route to a
solution --- have you read
http://www.postgresql.org/docs/view.php?version=7.3&idoc=0&file=explicit-joins.html
regards, tom lane
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