From: 中川 誠貴 <nakagawa@ivp.co.jp>
To: Dmitriy Igrishin <dmitigr@gmail.com>
Cc: pgsql-sql@postgresql.org
Subject: Re: why does seq scan instead of index scan
Date: Mon, 17 Jan 2011 10:25:22 +0900
Message-ID: <895509E8DA8F4649BBA565541CE333E9@IVPNAKAGAWAPC> (raw)
In-Reply-To: <AANLkTi=_EE6Fu_xv+U1f=4DwYgUJQ1+qGPN0FyMMMCRA@mail.gmail.com>
References: <49A94E2FF0F642B4ACBE09DB20CA5630@IVPNAKAGAWAPC>
<8294.1295027762@sss.pgh.pa.us>
<6A4B2F5F400049FEB3DF73B95BEA20EE@IVPNAKAGAWAPC>
<AANLkTi=_EE6Fu_xv+U1f=4DwYgUJQ1+qGPN0FyMMMCRA@mail.gmail.com>
Thank you very much.
I will try hstore columns.
Thanks.
From: Dmitriy Igrishin
Sent: Sunday, January 16, 2011 1:36 AM
To: 中川 誠貴
Cc: Tom Lane ; pgsql-sql@postgresql.org
Subject: Re: [SQL] why does seq scan instead of index scan
Hey,
To avoid creation of custom GiST-index you can use hstore,
which supports GiST and GIN indexes.
I propose you to add hstore column to the table and write trigger
function which will generate hstore from array on insert or update.
Or you can use hstore column instead of array.
Please, see http://www.postgresql.org/docs/9.0/static/hstore.html
2011/1/15 中川 誠貴 <nakagawa@ivp.co.jp>
Thank you for your response.
Are there any technique to index that query for like search on Text[] Columns?
Thanks.
Nakagawa Maskai
--------------------------------------------------
From: "Tom Lane" <tgl@sss.pgh.pa.us>
Sent: Saturday, January 15, 2011 2:56 AM
To: "中川 誠貴" <nakagawa@ivp.co.jp>
Cc: <pgsql-sql@postgresql.org>
Subject: Re: [SQL] why does seq scan instead of index scan
=?iso-2022-jp?B?GyRCQ2ZAbiEhQD81LhsoQg==?= <nakagawa@ivp.co.jp> writes:
I'm trying to use like 'xx%' search on Text[] column.
I thought it uses index scan. But actually it uses seq scan.
Why?
Those ANY expressions are not indexable.
regards, tom lane
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Subject: Re: why does seq scan instead of index scan
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