Oracle database management, tutorials, scripts, coding, programming and tips for database administrators
Oracle 12c offers a new way to match patterns in your data, the MATCH_RECOGNIZE function. Read on to see the syntax and the function in action.
The right statistics and histograms can provide improved performance for queries and reports. Read on to find out about Oracle’s new Hybrid histogram.
In a previous article Oracle declared bug 24390197 shouldn’t be; it’s the normal behavior for locally managed tablespaces with system-managed extents. Read on to see the details.
In Oracle 184.108.40.206 creating a table may fail even though space is available. Read on to see the conditions that can make this happen.
Careful testing and planning are crucial when deciding if an index is truly ‘unused’. Read on to see what could happen if testing isn’t thorough.
If you’re using invisible indexes, they may not be entirely ‘invisible’ to the optimizer. Read on to see why.
Without having an execution plan it’s difficult to know the degree of parallelism Oracle has selected. Read on to see how that can be reported.
Oracle’s REMAINDER function can return negative results; read on to see why and what can be done to work around the issue.
Oracle's calibrate_io procedure populates the data dictionary with disk 'performance' data to give the optimizer a fighting chance at a decent plan. Read on to see why the data it generates may not be the most accurate with respect to performance.
There are a lot of 'explanations' offered for the ORA-04091 error; read on to find out what is really going on and how to address the situation.
When using Oracle 220.127.116.11 in a Grid configuration the srvctl utility can change the group on the Oracle executables, creating problems with locating the spfile and with disk access.
Sometimes it's good to re-think how to write a query; set operations can provide performance benefits over 'straight SQL'. Read on to see an example of this in action.
Deletes may be more 'expensive' than the Oracle optimizer reports; read on to see why.
There may be times when you need to recover a single table and flashback isn't configured and the recycle bin is turned off. Using RMAN in Oracle 12c it's possible to restore and recover a single table. Read on to see how it's done.
Partitioning can be a real asset when used properly, as long as you don't run afoul of the maximum number of partitions Oracle will allow. Read on to learn the maximum number of partitions and discover some of the errors you can see if you try to exceed the limit.