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Re: View performance

From: Bruno Wolff III <bruno(at)wolff(dot)to>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: View performance
Date: 2002-12-26 20:36:56
Message-ID: 20021226203656.GB22984@wolff.to (view raw or flat)
Thread:
Lists: pgsql-performance
On Thu, Dec 26, 2002 at 14:42:39 -0500,
  Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> 
> which means that views using subselects in their targetlists will not be
> flattened into the calling query in 7.3.1.  This is not real desirable,
> but I see no other short-term fix.

Thanks for the explaination.

> In the particular case, your view definition seemed mighty inefficient
> anyway (it must recompute the subselects for each column retrieved from
> the view) so I think your rewrite is a good change.

I was naively expecting that the planner would notice the common subexpressions
and only compute them once.

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