| From: | Grzegorz Jaśkiewicz <gryzman(at)gmail(dot)com> |
|---|---|
| To: | Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at> |
| Cc: | "Hartman, Matthew *EXTERN*" <Matthew(dot)Hartman(at)krcc(dot)on(dot)ca>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Speeding up a query. |
| Date: | 2009-06-17 08:40:30 |
| Message-ID: | 2f4958ff0906170140q673ba1c6jf8eff4aa42798a22@mail.gmail.com |
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| Lists: | pgsql-performance |
On Wed, Jun 17, 2009 at 8:33 AM, Albe Laurenz<laurenz(dot)albe(at)wien(dot)gv(dot)at> wrote:
>
> I don't understand your data model well enough to understand
> the query, so I can only give you general hints (which you probably
> already know):
He is effectively joining same table 4 times in a for loop, to get
result, this is veeery ineffective.
imagine:
for(x)
for(x)
for(x)
for(x)
..
where X is number of rows in table matrix. not scarred yet ?
--
GJ
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