Troubleshooting
Problem
InfoSphere Guardium STAP has performance issue such as CPU usage high and many defunct processes spawned by STAP when running as 'guardium' user.
Symptom
When you run batch job, you find that STAP CPU usage is high. In the mean time, a lot of defunct processes are spawned by STAP. The batch job will hang. If you stop STAP, the batch job will run normally.
Cause
The issue specifically happens when you are running STAP as 'guardium' user, and you are monitoring shared memory. As we monitor shmat() calls, STAP may start to spawn defunct processes and consuming excessive CPU. The problem is that when STAP is not running as root, it must check the shared memory area using ipcs -ma, for which we may not have permission as 'guardium' user.
Environment
OS: AIX 7.1, DBMS: DB2
Diagnosing The Problem
Check the guard_tap.ini file, if you are running STAP with 'guardium' user (tap_run_as_root=0)
Resolving The Problem
Add the DB2 user to the Guardium group. In that way, the Guardium monitoring process will be able to see the shared memory contents, while still running as a user process.
To do this:
— stop DB2
— add the DB2 user (usually db2inst1) to the guardium group
— restart DB2
Adding the user can be done with the 'chgrpmem' command (as root):
$ chgrpmem -m + db2inst1 guardium
Was this topic helpful?
Document Information
Modified date:
08 November 2018
UID
swg21675442