Recently I've been working on improving the performance of a system that delivers files stored in postgresql as bytea data. I was surprised at just how much a penalty I find moving from a domain socket connection to a TCP connection, even localhost. For one particular 40MB file (nothing outragous) I see ~ 2.5 sec. to download w/ the domain socket, but ~ 45 sec for a TCP connection (either localhost, name of localhost, or from another machine 5 hops away (on campus - gigabit LAN) Similar numbers for 8.2.3 or 8.3.6 (on Linux/Debian etch + backports) So, why the 20 fold penalty for using TCP? Any clues on how to trace what's up in the network IO stack? Ross -- Ross Reedstrom, Ph.D. reedstrm@xxxxxxxx Systems Engineer & Admin, Research Scientist phone: 713-348-6166 The Connexions Project http://cnx.org fax: 713-348-3665 Rice University MS-375, Houston, TX 77005 GPG Key fingerprint = F023 82C8 9B0E 2CC6 0D8E F888 D3AE 810E 88F0 BEDE -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
