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Re: are views typically any faster/slower than equivilent joins?

From: Bruno Wolff III <bruno(at)wolff(dot)to>
To: Rod Taylor <rbt(at)rbt(dot)ca>
Cc: Brian Tarbox <btarbox(at)theworld(dot)com>,Postgresql Performance <pgsql-performance(at)postgresql(dot)org>
Subject: Re: are views typically any faster/slower than equivilent joins?
Date: 2003-06-01 05:43:37
Message-ID: 20030601054337.GD16259@wolff.to (view raw or flat)
Thread:
Lists: pgsql-performance
On Sun, Jun 01, 2003 at 00:02:39 -0400,
  Rod Taylor <rbt(at)rbt(dot)ca> wrote:
> 
> Some views such as unions will not be as fast as you would like, but
> thats a general issue with PostgreSQLs inability to throw away selects
> when it won't find results on one side of a union.
> 
> CREATE VIEW sales AS SELECT * FROM sales_archive_2002 UNION ALL SELECT *
> FROM sales_current;
> 
> 
> SELECT * FROM sales WHERE timestamp => CURRENT_TIMESTAMP - INTERVAL '1
> day';
> 
> The above query would not be so quick.

I thought some work had been done on pushing where conditions down into
unions? If so the above wouldn't be too bad. It would still look at
the archive table, but it should return no rows relatively quickly
assuming an appropiate index exists.

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Subject: Re: Index speeds up one row table (why)?
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