Insights into Statistics, Query Optimization and the Oracle Optimizer

  • 12c
    May 5, 2016

Optimizer Feature Differences Between Oracle Database Releases

Nigel Bayliss
Product Manager

Each time we release a new version of the Oracle Database we publish a white paper that covers what's in the new in the Oracle Optimizer. It's pretty comprehensive and it covers all of the headline features, but it doesn't go deep down in amongst the dragons.What if you want a closer look a what's changed in the Oracle Optimizer between releases? That's what this post is about.

You'll know that there's a database parameter called optimizer_features_enable (OFE). It can be used to restrict which Optimizer features are enabled in your database. You'll also know that you shouldn't use it like a magic wand, but it is very useful for the trick I have in mind here.

I've put together a script for you to check out. It's not earth-shatteringly new (as you'll realize if you take a look around the Internet) but I think that you'll find it useful. The principle behind its operation is pretty simple: it captures parameters and configuration settings for two different OFE values ( and, by default). Finally, it displays a comparison between the two sets of results. I think that the output is very interesting. I hope you think so too.


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Comments ( 3 )
  • guest Wednesday, May 11, 2016


    The link to the OFE details is not working, I'm getting the 404 error message on that.


  • nigelbayliss Thursday, May 12, 2016

    Hi - thanks for letting me know! The doc folks moved everything. :-O

  • Raghu Friday, July 13, 2018
    Interesting blog and something I wanted to keenly know. I am excited to see what you found.
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