"fuser" for Oracle files
- From: Herring Dave - dherri <Dave.Herring@xxxxxxxxxx>
- To: "Oracle-L (oracle-l@xxxxxxxxxxxxx)" <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 16 Aug 2012 18:37:16 +0000
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@xxxxxxxxxx
TEL 630.944.4762
MBL 630.430.5988
1501 Opus Pl, Downers Grove, IL 60515, USA
WWW.ACXIOM.COM
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