From: Jim C. Nasby <jnasby@pervasive.com>
To: nicky <nicky@valuecare.nl>
Cc: pgsql-performance@postgresql.org
Subject: Re: Speeding up query, Joining 55mil and 43mil records.
Date: Wed, 21 Jun 2006 13:48:03 -0500
Message-ID: <20060621184803.GC93655@pervasive.com> (raw)
In-Reply-To: <44994DE7.5070801@valuecare.nl>
References: <44994DE7.5070801@valuecare.nl>
On Wed, Jun 21, 2006 at 03:47:19PM +0200, nicky wrote:
> WHERE substr(t0.code,1,2) not in ('14','15','16','17')
> AND (substr(t0.correctie,4,1) <> '1' OR t0.correctie is null)
> AND EXTRACT(YEAR from t1.datum) > 2004;
How much data do you expect to be getting back from that where clause?
Unless you plan on inserting most of the table, some well-placed indexes
would probably help, and fixing the datum portion might as well
(depending on how far back the data goes). Specifically:
CREATE INDEX t0_code_partial ON t0(substr(code,1,2));
(yeah, I know t0 is an alias, but I already snipped the table name)
and
AND t1.datum >= '1/1/2005'
(might need to cast that to a date or whatever).
--
Jim C. Nasby, Sr. Engineering Consultant jnasby@pervasive.com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
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To: pgsql-performance@postgresql.org
Cc: jnasby@pervasive.com, nicky@valuecare.nl
Subject: Re: Speeding up query, Joining 55mil and 43mil records.
In-Reply-To: <20060621184803.GC93655@pervasive.com>
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