Received: from maia.hub.org (maia-4.hub.org [200.46.204.183]) by mail.postgresql.org (Postfix) with ESMTP id 04A706339C6 for ; Wed, 26 May 2010 15:33:24 -0300 (ADT) Received: from mail.postgresql.org ([200.46.204.86]) by maia.hub.org (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 37465-08 for ; Wed, 26 May 2010 18:33:16 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.7.6 Received: from ndjsnpf03.ndc.nasa.gov (ndjsnpf03.ndc.nasa.gov [198.117.1.123]) by mail.postgresql.org (Postfix) with ESMTP id BAF9063356E for ; Wed, 26 May 2010 15:33:16 -0300 (ADT) Received: from ndmsppt04.ndc.nasa.gov (ndmsppt04.ndc.nasa.gov [198.117.0.103]) by ndjsnpf03.ndc.nasa.gov (Postfix) with ESMTP id D54DF2D846E for ; Wed, 26 May 2010 13:33:14 -0500 (CDT) Received: from ndmshub01.ndc.nasa.gov (ndmshub01-pub.ndc.nasa.gov [198.117.0.160]) by ndmsppt04.ndc.nasa.gov (8.14.3/8.14.3) with ESMTP id o4QIX7c1001193 for ; Wed, 26 May 2010 13:33:14 -0500 Received: from LRC000959195.larc.nasa.gov (198.119.134.170) by smtp02.ndc.nasa.gov (198.117.0.160) with Microsoft SMTP Server (TLS) id 8.1.393.1; Wed, 26 May 2010 13:33:07 -0500 Message-ID: <4BFD695D.4030005@nasa.gov> Date: Wed, 26 May 2010 14:33:01 -0400 From: "Maria L. Wilson" Reply-To: Maria.L.Wilson-1@nasa.gov Organization: SSAI User-Agent: Thunderbird 2.0.0.24 (Macintosh/20100228) MIME-Version: 1.0 To: "pgsql-admin@postgresql.org" Subject: Indexes advantageous on foreign key columns Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=fsecure engine=1.12.8161:2.4.5, 1.2.40, 4.0.166 definitions=2010-05-26_04:2010-02-06, 2010-05-26, 2010-05-26 signatures=0 X-Virus-Scanned: Maia Mailguard 1.0.1 X-Spam-Status: No, hits=-1.51 tagged_above=-10 required=5 tests=BAYES_50=0.8, RCVD_IN_DNSWL_MED=-2.3, T_RP_MATCHES_RCVD=-0.01 X-Spam-Level: X-Archive-Number: 201005/255 X-Sequence-Number: 34728 Was hoping that someone would like to discuss the need for indexes on columns that are referenced in a foreign key. Are they necessary? Are they worth the overhead? PostgreSQL version 8.4 thanks, Maria Wilson Nasa, Langley Research Center Hampton, Virginia 23681