Received: from maia.hub.org (maia-2.hub.org [200.46.204.251]) by mail.postgresql.org (Postfix) with ESMTP id C4BB31337C17 for ; Wed, 23 Feb 2011 17:19:01 -0400 (AST) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.251]) (amavisd-maia, port 10024) with ESMTP id 40892-01-8 for ; Wed, 23 Feb 2011 21:18:54 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from moutng.kundenserver.de (moutng.kundenserver.de [212.227.17.10]) by mail.postgresql.org (Postfix) with ESMTP id C758A1337C2E for ; Wed, 23 Feb 2011 17:17:22 -0400 (AST) Received: from [192.168.1.6] (mail.highperformancepostgresql.com [71.179.240.8]) by mrelayeu.kundenserver.de (node=mrbap2) with ESMTP (Nemesis) id 0M1QSH-1QBwEZ0dXl-00u3uf; Wed, 23 Feb 2011 22:17:19 +0100 Message-ID: <4D65795C.20404@2ndquadrant.com> Date: Wed, 23 Feb 2011 16:17:16 -0500 From: Greg Smith User-Agent: Thunderbird 2.0.0.24 (X11/20100317) MIME-Version: 1.0 To: Benjamin Krajmalnik CC: pgsql-performance@postgresql.org Subject: Re: Unused indices References: In-Reply-To: Content-Type: multipart/alternative; boundary="------------060205020209060205030702" X-Provags-ID: V02:K0:P1tVal12X4lzj6Dux/J67xjtqMrQReqv+BDlPmpl3yU P/c9RGQ8h6dCl1r1eA7ht1qDCkooLPejdf2A9DvWlqO+I2/RJD roWvZ/f1e5CJQ+BcCBo0gW1lFGZypoy+9dAwFcYcNV5gK7ctsq ESXb5DugzRkefsmrfrRASARIwSUe/zigYD4IAC0XDmmcmvSJFO vbVrSpwxn1glrMo/u4XZA2OJ1Zkt26vwmqqkesZKLk= X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.899 tagged_above=-10 required=5 tests=BAYES_00=-1.9, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_NONE=-0.0001 X-Spam-Level: X-Archive-Number: 201102/460 X-Sequence-Number: 42598 This is a multi-part message in MIME format. --------------060205020209060205030702 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Benjamin Krajmalnik wrote: > > > Index Scans 0 > > Index Tuples Read 0 > > Index Tuples Fetched 0 > > Index Blocks Read 834389 > > Index Blocks Hit 247283300 > > Index Size 1752 kB > > > > > > Since there are no index scans, would it be safe to remove this one? > Yes. The block usage you're seeing there reflects the activity from maintaining the index. But since it isn't ever being used for queries, with zero scans and zero rows it's delivered to clients, it's not doing you any good. Might as well reclaim your 1.7MB of disk space and reduce overhead by removing it. -- Greg Smith 2ndQuadrant US greg@2ndQuadrant.com Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us "PostgreSQL 9.0 High Performance": http://www.2ndQuadrant.com/books --------------060205020209060205030702 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Benjamin Krajmalnik wrote:

Index Scans        0

Index Tuples Read           0

Index Tuples Fetched    0

Index Blocks Read           834389

Index Blocks Hit                247283300

Index Size           1752 kB

Since there are no index scans, would it be safe to remove this one?

Yes. The block usage you're seeing there reflects the activity from maintaining the index. But since it isn't ever being used for queries, with zero scans and zero rows it's delivered to clients, it's not doing you any good. Might as well reclaim your 1.7MB of disk space and reduce overhead by removing it.

-- 
Greg Smith   2ndQuadrant US    greg@2ndQuadrant.com   Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support  www.2ndQuadrant.us
"PostgreSQL 9.0 High Performance": http://www.2ndQuadrant.com/books

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