Lists: | pgsql-admin |
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From: | "Jeff Madison" <jeff(at)ikano(dot)com> |
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To: | <pgsql-admin(at)postgresql(dot)org> |
Subject: | Large Join Dies |
Date: | 2002-04-18 00:16:23 |
Message-ID: | 02da01c1e66e$45aa3c20$58c2d0cd@JEFF |
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Lists: | pgsql-admin |
Running Postgres 7.1.4 from RedHad RPM on RedHat 7.2. When ever we run
a query where we are joining more than 3 tables the query never returns.
Any ideas?
Jeff
From: | Jeremy Buchmann <jeremy(at)wellsgaming(dot)com> |
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To: | Jeff Madison <jeff(at)ikano(dot)com> |
Cc: | pgsql-admin(at)postgresql(dot)org |
Subject: | Re: Large Join Dies |
Date: | 2002-04-18 00:35:28 |
Message-ID: | 3CBE14D0.4030205@wellsgaming.com |
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Lists: | pgsql-admin |
Jeff Madison wrote:
> Running Postgres 7.1.4 from RedHad RPM on RedHat 7.2. When ever we run
> a query where we are joining more than 3 tables the query never returns.
> Any ideas?
>
> Jeff
Jeff,
It would help to know things like:
* What the exact query is (and an EXPLAIN of the query)
* How big the tables are (and the general schema)
* What kind of hardware you're running on
Off the top of my head, I would say check your table1.key = table2.key
join constraints. More than three tables leads to a lot of constraints
and if you miss just one, you'll get a big cartesian product that will
make the query seemingly go on forever even if your tables are of moderate
size.
--Jeremy