Category: Linux

Linux threads and CPU affinity

Linux provides native threading capabilities. This allows a program to run with multiple processes all accessing the same shared data, without the headache of Interprocess Communication (IPC) calls. Essentially, a single process makes calls to the system pthread library to…

Printing counts of page requests

Simple post today, this just strips the request parameter string of a URL recorded in the Apache style log, and groups the times each base page was requested in sorted order. -bash-4.1$ grep -v login /opt/jboss/versions/jboss-eap-5.1/jboss-as/server/q_ecm_01/log/localhost_access_log.2012-12-12.log | grep jsp |…

Tracing SQL across the wire

This can be really useful in place of database tracing, especially when you want to see the action the *application* takes, and not just what it does in the database. [user@************** common]# tcpdump -A -nn port 1521 | \ >…

Quiet svn+ssh

While issuing various svn commands and using the svn+ssh protocol, we found that the output of /etc/issue could really clutter up the screen. We added the following in the $HOME/.ssh/config LogLevel quiet This eliminated the output of /etc/issue.

Allowing oracle to read /var/log/messages

The system log sometimes contains important information for troubleshooting cluster issues. setfacl -m u:oracle:r /var/log/messages On RHAT, the ACL is preserved so when logrotate is run, oracle will be able to read the new /var/log/messages file and the “old” ones…

tcpdump to see Oracle errors

Not all exceptions are created equally, and most you can ignore (the one below you can, in general). However, if you have to troubleshoot on JBOSS (or anywhere a Linux application connects to an Oracle database), what is below is…