Schedule Automatic STATSPACK Data Collection

Oracle Tips by Burleson Consulting
Don Burleson

After we have verified that STATSPACK is installed and working, we can schedule automatic data collection. By using the statsauto.sql script we can automatically schedule an hourly data collection for STATSPACK. The statsauto.sql script contains the following directive:

SQL> execute dbms_job.submit(:jobno, 'statspack.snap;',
trunc(sysdate+1/24,'HH'), 'trunc(SYSDATE+1/24,''HH'')', TRUE, :instno);

The important thing to note in this call to dbms_job.submit is the execution interval. The SYSDATE+1/24 is the interval that is stored in the dba_jobs view to produce hourly snapshots. You can change this as follows for different sample times. There are 1,440 minutes in a day, and you can use this figure to adjust the execution times.

SQL> execute dbms_job.submit(:jobno, 'statspack.snap;',
trunc(sysdate+1/144,'MI'), 'trunc(SYSDATE+1/144,''MI'')', TRUE, :instno);

In the real world, you may have times where you want to sample the database over short time intervals. For example, if you have noticed that a performance problem happens every day between 4:00 P.M. and 5:00 P.M., you can request more frequent snapshots during this period.

For normal use, you probably want to accept the hourly default and execute a snapshot every hour. Below is the standard output from running the statsauto.sql script:

SQL> connect perfstat/perfstat;
Connected.
SQL> @statsauto
PL/SQL procedure successfully completed.

Job number for automated statistics collection for this instance

Note that this job number is needed when modifying or removing the job:

JOBNO
----------
1

Job queue process

Below is the current setting of the job_queue_processes init.ora parameter - the value for this parameter must be greater than 0 to use automatic statistics gathering:

NAME TYPE VALUE
------------------------------------ ------- -----------------------------
job_queue_processes integer 1

Next scheduled run
~~~~~~~~~~~~~~~~~~
The next scheduled run for this job is:

JOB NEXT_DATE NEXT_SEC
---------- --------- --------
1 12-MAY-02 16:00:00

We can now see that a STATSPACK snapshot will automatically be executed every hour. We see that this is scheduled as job number 1, and we can use this job number to cancel this collection at any time using the dbms_job.remove procedure:

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