Received: from localhost (maia-3.hub.org [200.46.204.184]) by postgresql.org (Postfix) with ESMTP id 5C2099FC13F for ; Fri, 27 Apr 2007 13:26:02 -0300 (ADT) Received: from postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.184]) (amavisd-maia, port 10024) with ESMTP id 96275-04 for ; Fri, 27 Apr 2007 13:25:58 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.4 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id 6268C9FC135 for ; Fri, 27 Apr 2007 13:25:59 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.13.6/8.13.6) with ESMTP id l3RGPv5w015874; Fri, 27 Apr 2007 12:25:57 -0400 (EDT) To: sid@etsy.com cc: pgsql-performance@postgresql.org Subject: Re: How can fixed and variable width columns perform similarly? In-reply-to: <50444.209.51.183.100.1177687911.squirrel@mailbox.etsy.com> References: <50444.209.51.183.100.1177687911.squirrel@mailbox.etsy.com> Comments: In-reply-to "Siddharth Anand" message dated "Fri, 27 Apr 2007 08:31:51 -0700" Date: Fri, 27 Apr 2007 12:25:57 -0400 Message-ID: <15873.1177691157@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200704/474 X-Sequence-Number: 24351 "Siddharth Anand" writes: > How can a field that doesn't have a limit like "text" perform similarly to > char varying(128), for example? At some point, we need to write data to > disk. The more data that needs to be written, the longer the disk write > will take, especially when it requires finding free sectors to write to. What's your point? If you're not going to put more than 128 characters in the field, there's no difference in the amount of data involved. regards, tom lane