Received: from maia.hub.org (maia-3.hub.org [200.46.204.243]) by mail.postgresql.org (Postfix) with ESMTP id BA7C91337B83 for ; Sat, 15 Jan 2011 01:19:43 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.243]) (amavisd-maia, port 10024) with ESMTP id 12152-09 for ; Sat, 15 Jan 2011 05:19:35 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from smtpsvr.ivp.ne.jp (smtpsvr.ivp.ne.jp [59.159.236.17]) by mail.postgresql.org (Postfix) with ESMTP id 19B891337B8A for ; Sat, 15 Jan 2011 01:19:34 -0400 (AST) Received: from IVPNAKAGAWAPC (ivpb.ivp.co.jp [219.96.232.34]) by smtpsvr.ivp.ne.jp (8.13.8/3.7W) with ESMTP id p0F5JWsl030005; Sat, 15 Jan 2011 14:19:32 +0900 Message-ID: <6A4B2F5F400049FEB3DF73B95BEA20EE@IVPNAKAGAWAPC> From: =?iso-2022-jp?B?GyRCQ2ZAbiEhQD81LhsoQg==?= To: "Tom Lane" Cc: References: <49A94E2FF0F642B4ACBE09DB20CA5630@IVPNAKAGAWAPC> <8294.1295027762@sss.pgh.pa.us> In-Reply-To: <8294.1295027762@sss.pgh.pa.us> Subject: Re: why does seq scan instead of index scan Date: Sat, 15 Jan 2011 14:19:34 +0900 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-2022-jp"; reply-type=original Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.461 tagged_above=-5 required=5 tests=BAYES_00=-1.9, STOX_REPLY_TYPE=0.439 X-Spam-Level: X-Archive-Number: 201101/41 X-Sequence-Number: 34988 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" Sent: Saturday, January 15, 2011 2:56 AM To: "中川　誠貴" Cc: Subject: Re: [SQL] why does seq scan instead of index scan > =?iso-2022-jp?B?GyRCQ2ZAbiEhQD81LhsoQg==?= 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 > > -- > Sent via pgsql-sql mailing list (pgsql-sql@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-sql