Oracle database management, tutorials, scripts, coding, programming and tips for database administrators
Large transactions can take considerable time to rollback once they are stopped. Read on to see how to monitor rollback progress from another session.
Running procedures and functions outside of the package context can cause issues, especially with dependencies. Read on to see how ACCESSIBLE BY can prevent 'unauthorized' access to procedures and functions.
Parallel query buffers can be numerous and, as a result, may wait for an allocation latch. Read on to see why larger parallel degree settings are more likely to encounter this latch.
Execution plans can be very helpful when diagnosing problems but be careful how you generate them as autotrace can lie to you. Read on to see how to generate reliable execution plans.
Sometimes it's possible to track down an object causing an en-queue wait from an ASH report. Read on to see how such an investigation begins and what information may be available.
Mutexes differ from latches in a number of ways. Read on to see how they differ from latches, what modes they can be acquired in, and their relative efficiency compared to latches.
Oracle latches are interesting items that can protect, and sometimes hinder, object access. Read on to see what they are, how they work and how they can sometimes cause problems.
Extended string lengths can be very beneficial but they can also be an impediment to index and constraint creation. Read on to see what the problems are and how to get around them.
Histograms have improved greatly over the years, yet there are still those who won't use them. Read on to learn what they do and why they may not be as bad as some say.
Interestingly, you can create a B-tree index on a BLOB column; read on to see how to do it and just how useful, or not, it might be.
When all else fails it may be necessary to tell Oracle that index access is the way to go. Read on to see what parameter is used, how to set it, and what surprises you may find after you do.
Using NOLOGGING is a time-saver, some say, but is it really? Read on to see why it may not be and how it can get you into trouble.
Many enterprises are requiring user notification of session monitoring at login, at both the server and database level. Read on to see how to enable this feature and provide custom text.
The new Unified Audit Trail in Oracle 12c can provide advantages over the older audit trail. Read on to see how to configure it and how to test the policy.
With all of the metrics Oracle provides, it can be easy to want to tune a lot of areas. Read on to see why not every metric needs tuning.