From: | "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov> |
---|---|
To: | "Grant Masan" <grant(dot)massan(at)gmail(dot)com> |
Cc: | "Jeff Janes" <jeff(dot)janes(at)gmail(dot)com>, <pgsql-performance(at)postgresql(dot)org> |
Subject: | Re: Problem with database performance, Debian 4gb ram ? |
Date: | 2009-11-06 15:26:27 |
Message-ID: | 4AF3EBC3020000250002C329@gw.wicourts.gov |
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Lists: | pgsql-general pgsql-performance |
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Grant Masan <grant(dot)massan(at)gmail(dot)com> wrote:
> CREATE FUNCTION ... RETURNS SETOF ...
> FOR ... IN SELECT ... LOOP
> FOR ... IN SELECT ... LOOP
> FOR ... IN SELECT ... LOOP
>
> RETURN NEXT text_output;
>
> END LOOP;
> END LOOP;
> END LOOP;
I don't have time to work through the logic of all this to try to
discern what your goal is; but in my experience, such procedural code
can usually be rewritten as a single query. The results are typically
orders of magnitude better.
> SELECT * FROM info_tool(linest,date,date)
> "Function Scan on info_tool (cost=0.00..260.00 rows=1000 width=108)
> (actual time=437712.611..437712.629 rows=14 loops=1)"
> "Total runtime: 437712.686 ms"
To get useful information you need EXPLAIN ANALYZE from statements
inside the function, not of the execution of the function.
-Kevin
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