Author Archives: Bobby

We are having challenges with queries that spend most of their time on these waits: enq: TS – contention This wait indicates that a query on one instance of a RAC system is causing its instance to add temp space … Continue reading →

I thought it might be helpful to show what sar -d returns during a disk issue.  Sorry, I only have a screenshot I took during the problem.  Click on the smaller image to see the full size jpeg. This was a … Continue reading →

Worked on the scripts in this zip today: https://www.bobbydurrettdba.com/uploads/sessionprofiledbahist.zip I wanted to see a session profile from the DBA_HIST_ACTIVE_SESS_HISTORY view.  My idea was to include the time the session was inactive as well as the time it was waiting on an event or … Continue reading →

Slides for a presentation on Exadata that I did at work: https://www.bobbydurrettdba.com/uploads/ExadataDistinctives.ppt Hopefully I balanced out the good and bad.  Exadata has some good features but we have hit a large number of bugs.  Given adequate testing you could benefit … Continue reading →

The autotask clients run in their own resource consumer groups.  So, stats, space, and SQL tuning tasks have some consumer groups that you have to include in your own plans if your plan will be active while the window for these tasks … Continue reading →

You many wonder why you should care about Oracle Resource Manager wait events.  You should care because every Oracle 11g database uses Resource Manager by default during the maintenance windows.  So, even if you have not intentionally configured RM you may … Continue reading →

Found a couple of Oracle blog aggregators.  These sites combine the many Oracle DBA blogs into single sites. http://www.orafaq.com/ http://orana.info/ – NO LONGER EXISTS It looks like Oracle has an aggregator for their own employees: https://blogs.oracle.com/ Pretty cool. – Bobby

I’ve been using the view DBA_HIST_ACTIVE_SESS_HISTORY to investigate problems lately.  I’ve found this useful for both performance problems and hangs.  I’ve done some more complicated things, but I find that just dumping out every column of the view for a … Continue reading →

Found a helpful PL/SQL block in this presentation: http://www.sagelogix.com/idc/groups/public/documents/sagelogix-presentation/sage016048.pdf – NO LONGER EXISTS This shows you which events are set – i.e. by an alter system set events command.  I modified this to have a larger range of event values … Continue reading →

Found a cool package and procedure while working on a problem today. DBMS_SPACE.SPACE_USAGE This takes a segment and shows how many blocks are free or partially filled. In our case we hit a bug which resulting in tons of unformatted … Continue reading →