Friday, July 4, 2025

How to change Oracle AWR snapshots generation frequency

 The default frequency (automatic) of generation of Oracle Automatic Workload Repository (AWR) is every 1 hour (60 minutes). Sometimes, an Oracle DBA might have set this to generate more frequently, say, every 15 minutes i.e 4 times an hour to troubleshoot a performance issue and later would have forgotten to set it back to 1 hour frequency. 

This will fill up the SYSAUX tablespace very quickly. Please follow the below list of instructions to reset it back to 1 hour frequency.

This is tested in an Oracle 19c database.


select snap_interval, retention from dba_hist_wr_control;

If it is run every 15 minutes, then the output will show +00000 00:15:00.0

execute dbms_workload_repository.modify_snapshot_settings(interval => 60);

The AWR snapshots will now be generated every 1 hour instead of every 15 minutes.

select snap_interval, retention from dba_hist_wr_control;

The output should now show +00000 01:00:00.0


Thursday, July 3, 2025

Disable Oracle AHF in ExaCC Exadata

Some versions of Oracle AHF (Autonomous Health Framework) utility can cause performance overhead in Exadata Cloud@Customer (ExaCC) such as consuming more memory on database server nodes and causing high load on these servers and it is not required to be running all the time in the background. Oracle AHF is a combination of mostly TFA (Trace File Analyzer), Exachk and Oracheck utilities and this tool gathers various diagnostic information.

It is advised that this tool be disabled and started only when required, say, if Oracle Support team wants to gather some diagnostic information as part of a Service Request (SR) for troubleshooting an issue. Once the gathering of the diagnostic information is completed, then stop and disable it again.

Some useful commands of Oracle Trace File Analyzer (TFA) are below.

How to check the file path of the utility

which tfactl

How to check the version of the utility

tfactl version

How to check if AHF utility is running

tfactl status

How to disable automatic startup

Login as root to the database server

tfactl disable

How to enable automatic startup

Login as root to the database server

tfactl enable

How to perform manual stop

Login as root to the database server

tfactl stop

How to perform manual startup

Login as root to the database server

tfactl start