From: PFC <lists@peufeu.com>
To: Zoltan Boszormenyi <zboszor@dunaweb.hu>
To: pgsql-performance@postgresql.org
Subject: Re: Auto-tuning a VIEW?
Date: Wed, 14 Dec 2005 22:38:49 +0100
Message-ID: <op.s1smezd8cigqcu@peufeu.com> (raw)
In-Reply-To: <43A08EF5.4060306@dunaweb.hu>
References: <43A08EF5.4060306@dunaweb.hu>
> create view v1 (code,num) as
> select 'AAA',id from table1
> union
> select 'BBB',id from table2;
As your rows are, by definition, distinct between each subquery, you
should use UNION ALL instead of UNION to save postgres the trouble of
hunting non-existing duplicates. This will save you a few sorts.
> select * from v1 where code||num = 'AAA2005000001';
Why don't you use code='AAA' and num='2005000001' ?
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To: pgsql-performance@postgresql.org
Cc: lists@peufeu.com, zboszor@dunaweb.hu
Subject: Re: Auto-tuning a VIEW?
In-Reply-To: <op.s1smezd8cigqcu@peufeu.com>
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