Automated Statistics Gathering

The actual code for the full DBMS_REVEALNET.RUNNING_STATS procedure runs to 12 or more pages and reports on up to nearly a hundred statistics (some are based on latch statistics or contention statistics so the exact number monitored changes). The private procedure write_out contained in the master procedure RUNNING_STATS uses one of two tables, Remote DBA_RUNNING_STATS or Remote DBA_TEMP to hold all of the retrieved values. If the “is_interactive” flag is set to TRUE the Remote DBA_TEMP table is used. If the “is_interactive” flag is set to the default, FALSE, then the Remote DBA_RUNNING_STATS table is used. The Remote DBA_TEMP table only holds one set of values and is deleted before use. The Remote DBA_RUNNING_STATS table keeps an ongoing set of statistics taken at whatever interval is desired (usually 15 minutes). This allows the procedure to double duty, either as an instant monitor script (when combined with a SELECT against the Remote DBA_TEMP table) or as a background statistics collection script.

Using the DBMS_JOB.SUBMIT procedure, the command to submit the RUNNING_STATS procedure to the job queue would be:

VARIABLE x NUMBER;

EXECUTE DBMS_JOB.SUBMIT(:x,’BEGIN DBMS_REVEALNET.RUNNING_STATS(FALSE); END;’, SYSDATE,’SYSDATE+(15/14440)’);

Notice how the BEGIN-END; block structure is used. This block structure is used to prevent some problems that have been reported when a straight procedure call is made to the job queue. Notice that the interval is specified as a character string: ’SYSDATE+(15/14440)’ that evaluates to a future date. The interval will tend to creep unless the string is specified using concatenated date values. Also notice how the value for “is_interactive” is specified, even though it will default to FALSE, this is to reduce confusion when the job is viewed using the Remote DBA_JOBS view.

SEE CODE DEPOT FOR FULL SCRIPTS

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