From 10g onwards the MMON process wakes up by default every hour and does statistics collection for AWR (Automatic Workload Repository).
10g provides the following procedure for modify this statistics collection routine:
DBMS_WORKLOAD_REPOSITORY.MODIFY_SNAPSHOT_SETTINGS((
retention IN NUMBER DEFAULT NULL,
interval IN NUMBER DEFAULT NULL,
dbid IN NUMBER DEFAULT NULL);
This example changes the interval setting to two hours and the retention setting to two weeks for the local database:
execute dbms_workload_repository.modify_snapshot_settings(interval => 120,retention => 20160);
If you query the DBA_HIST_WR_CONTROL table after this procedure is executed, you will see the changes to these settings.
execute DBMS_WORKLOAD_REPOSITORY.MODIFY_SNAPSHOT_SETTINGS(interval => 0);
By setting the value of the interval as 0 we set the new interval between each snapshot collection as 110 years.