Re: [SQL] Good Optimization - Mailing list pgsql-sql

From Bruce Momjian
Subject Re: [SQL] Good Optimization
Date
Msg-id 199907071645.MAA01466@candle.pha.pa.us
Whole thread Raw
In response to Re: [SQL] Good Optimization  ("Roderick A. Anderson" <raanders@altoplanos.net>)
List pgsql-sql
> Also if the optimizer works similar to Oracle then the order of
> where statements would also help in actual performance.  I'm mostly a
> lurker on this list but have never seen anything about this issue.
>    When using Oracle, and won't it be nice when people mention PostgreSQL
> functionality when comparing other databases, the statements at the
> bottom should be the most restrictive and joins should be near the top.
> 
>     select * 
>       from po,tickets
>      where po_id=material_po
>        and po_id=8888 ;
> 
> Would be the best.  Whereas
> 
>     select *
>       from po,tickets
>      where po_id=8888
>        and po_id=material_po;
> 
> would do the join then select those tuples that have a po_id of 8888.
> 
> Of course this is probably what PostgreSQL is doing already without a
> requirement for the positioning.

This is not your mother's database.  We don't care about statement
ordering.  :-)


--  Bruce Momjian                        |  http://www.op.net/~candle maillist@candle.pha.pa.us            |  (610)
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