From: | "Jonah H(dot) Harris" <jonah(dot)harris(at)gmail(dot)com> |
---|---|
To: | "Josh Trutwin" <josh(at)trutwins(dot)homeip(dot)net> |
Cc: | pgsql-performance(at)postgresql(dot)org |
Subject: | Re: PostgreSQL vs MySQL, and FreeBSD |
Date: | 2007-11-16 20:53:51 |
Message-ID: | 36e682920711161253l4376c96ap95fb494c7e24874f@mail.gmail.com |
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Thread: | |
Lists: | pgsql-performance |
On Nov 16, 2007 3:36 PM, Josh Trutwin <josh(at)trutwins(dot)homeip(dot)net> wrote:
> > Agreed. IMHO, there's nothing wrong with nested-loop join as long
> > as it's being used properly.
>
> Can you explain further please? (I'm not disagreeing with you, just
> want to know when nested loops are not used properly - does the
> planner make mistakes that you have to watch out for?)
As long as statistics are updated properly, it's generally not an
issue. You just don't want the system using a nested-loop join
incorrectly (like when table sizes are equal, the outer table is
larger than the inner table, or the inner table itself is overly
large).
--
Jonah H. Harris, Sr. Software Architect | phone: 732.331.1324
EnterpriseDB Corporation | fax: 732.331.1301
499 Thornall Street, 2nd Floor | jonah(dot)harris(at)enterprisedb(dot)com
Edison, NJ 08837 | http://www.enterprisedb.com/
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