"fuser" for Oracle files
Date: Thu, 16 Aug 2012 18:37:16 +0000
Message-ID: <BD475CE0B3EE894DA0CAB36CE2F7DEB4E3D00C6E_at_LITIGMBCRP02.Corp.Acxiom.net>
Folks,
This is probably old news to most, but in performing regular cleanup of [a|b|u]dump directories I've found that calls to "fuser" can have a large impact on the performance of the cleanup script. Normally we validate any Oracle audit/trace/logfile as for being opened or not, using "fuser", before removing or gzip'ing it. Using "strace" to see what's going on I saw that "fuser" has to check every /proc for the given file (like a full scan), which makes sense since use of it is saying "tell me all processes that have this file opened". On a system with 1000's of files to check and 1000's of processes running, each check can take a relatively long time.
The good news is nearly all Oracle audit and tracefiles have the owner's PID as part of the filename, so with that it's now like an indexed read. Individual file checks went from 0m3.144s to 0m0.003s.
The testing was done on RHEL4.6, Oracle 10.2.0.2
DAVID HERRING
DBA
Acxiom Corporation
EML dave.herring_at_acxiom.com TEL 630.944.4762 MBL 630.430.5988
1501 Opus Pl, Downers Grove, IL 60515, USA WWW.ACXIOM.COM
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-- http://www.freelists.org/webpage/oracle-lReceived on Thu Aug 16 2012 - 13:37:16 CDT