Message-ID: <46BDC091.4090109@commandprompt.com>
Date: Sat, 11 Aug 2007 06:58:41 -0700
From: "Joshua D. Drake" <jd@commandprompt.com>
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To: Heikki Linnakangas <heikki@enterprisedb.com>
CC: pgsql-sql <pgsql-sql@postgresql.org>,
	postgresql performance list <pgsql-performance@postgresql.org>
Subject: Re: Performance on writable views
References: <20070808124054.GC27936@nibiru.local>
	<46BD687E.1040100@enterprisedb.com>
In-Reply-To: <46BD687E.1040100@enterprisedb.com>
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Heikki Linnakangas wrote:
> Enrico Weigelt wrote:
>> I'm often using writable views as interfaces to clients, so 
>> they only see "virtual" objects and never have to cope with
>> the actual storage, ie. to give some client an totally 
>> denormalized view of certain things, containing only those 
>> information required for certain kind of operations. 

>> Now I've got the strange feeling that this makes updates
>> slow, since it always has to run the whole view query to
>> fetch an record to be updated (ie. to get OLD.*).
> 
> There is some overhead in rewriting the query, but it shouldn't be
> significantly slower than issuing the statements behind the view
> directly. I wouldn't worry about it, unless you have concrete evidence
> that it's causing problems.

I don't know about that, at least when using rules for partitioning the
impact can be significant in comparison to triggers.

It may make sense for him to push this stuff to stored procs instead.

Joshua D. Drake


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