EM 13c – Enhancements to DB Optimizer Statistics Console

Optimizer Statistics Console

There’s a lot of new features in Enterprise Manager 13c (EM 13c) that the DBAs will love.   One of the things I’d heard customers complain about was the lack of visibility into the statistics jobs that run in the target database using DBMS_SCHEDULER. The enhanced DB Optimizer Statistics Console provides a central place to manage database statistics, view a summary of all object status, and the status and performance of the statistics jobs that have run.   To access the console, from a database target select Performance / SQL / Optimizer Statistics.

The Operations, Configure and Status sections haven’t changed much.  In the Operations section you can Gather, Lock, Unlock, View, Restore and Delete statistics.  From the Configure section you can easily adjust Global Statistics Gathering Options, Object Level or make changes to the Auto Task and view SPA Validation Resultsem13db3

The new notable new features here are the breakdown of Statistics Gathering tasks and the Jobs List.  From the chart, you can quickly see if you have job failures that might be affecting your performance.  In the status chart, you can identify if you have State statistics that need attention.

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Drilling down into the Statistics Gathering Job List or Auto Tasks will bring up a detailed report of the job run.

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Not a huge change, but hopefully one that will make the DBA’s life easier and provide better insight when evaluating database statistics!

 

Monitoring Archive Area % Used on Cluster Databases

One of the most critical events to monitor on an Oracle Database is your archive area. If the archive area fills up, your database will halt until it can continue to archive the redo logs. If your archive destination is set to a file system, then the Archive Area % Used metric is often the best way to go. This metric allows you to monitor a particular file system for the percentage space that has been used. However, there are a couple of things to be aware of for this critical metric.

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Fast Recovery Area for Archive Destination

If you are using Fast Recovery Area (FRA) for the archive destination and the destination is set to USE_DB_RECOVERY_FILE_DEST, you may notice that the Archive Area % Used metric does not trigger anymore. Instead you will see the Recovery Area % Used metric trigger when it hits a Warning threshold of 85% full, and Critical of 97% full. As this metric is controlled by the server side database thresholds it cannot be modified by Enterprise Manager (see MOS Note 428473.1 for more information). Thresholds of 85/97 are not sufficient for some of the larger, busier databases. This may not give you enough time to kickoff a backup and clear enough logs before the archiver hangs. If you need different thresholds, you can easily accomplish this by creating a Metric Extension (ME) and setting thresholds to your desired values.  This blog will walk through an example of creating an ME to monitor archive on FRA destinations, for more information on ME’s and how they can be used, refer to the Oracle Enterprise Manager Cloud Control Administrator’s Guide.  

 

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