default

A change in Oracle 12.2 and 19c with MV Refresh Stats Collection

It’s not easy for me to put the topic into a searchable title for this blog post. The feature or change I will write about today came in actually with Oracle Database 12.2.0.1. But since many of you will move directly from Oracle 11.2.0.4 or 12.1.0.2 to 19c, the Long Term Support release, it may affect you as well. So let me explain a change in Oracle 12.2 and 19c with MV Refresh Stats Collection.

 

A customer story

The local Support team asked me a few weeks ago whether I have heard …

Continue reading...

Should you enable _fix_controls with DBMS_OPTIM_BUNDLE?

Today, Paul mailed me asking a question we internally discussed many times in the past weeks: Should you enable _fix_controls with DBMS_OPTIM_BUNDLE? And there is no easy simple answer. But I can give a recommendation based on my experience from many projects.

DBMS_OPTIM_BUNDLE – a quick recap

Just in case you haven’t dealt with DBMS_OPTIM_BUNDLE recently, here is a quick recap.

With below procedure, you can list the available potentially behavior changing optimizer fixes in the current patch bundle – and you can turn them on or off at will:

SQL> set serveroutput on;
Continue reading...

Oracle 12.2 and higher: Set _cursor_obsolete_threshold to old default

Sometimes development groups change default parameter settings because it fits well for a specific feature. This has happened with _cursor_obsolete_threshold in Oracle Database 12.2. But there’s now an official recommendation for Oracle 12.2 and higher: Set _cursor_obsolete_threshold to old default.

What is _cursor_obsolete_threshold?

First of all, this is obviously an underscore parameter. And usually the policy is: Don’t change underscore parameters unless either you clearly understand what you are changing. Or unless Oracle Support (or another Oracle authority) advises you to do.

Oracle 12.2 and higher: Set _cursor_obsolete_threshold to old default

Photo by Jakub Gorajek on Unsplash

We introduced this parameter in Oracle 11.2.0.3 for an issue of growing

Continue reading...