We have moved!

You might have been wondering why things had gone so quiet on the Optimizer development team's blog Optimizer Magic over the last few months. Well the blog has moved to blogs.oracle.com/optimizer. All of the old articles have moved too and we plan to be a lot more active at our new home, with at least one new post every month.


Maria Colgan

Explain adaptive cursor sharing behavior with cursor_sharing = similar and force.

This post has moved to
http://blogs.oracle.com/optimizer/entry/explain_adaptive_cursor_sharing_behavior_with_cursor_sharing_similar_and_force

Upgrading from 9i to 11g and the implicit migration from RBO

This blog post has moved to
http://blogs.oracle.com/optimizer/entry/upgrading_from_9i_to_11g_and_the_implicit_migration_from_rbo

Maria Colgan

What should I do with old hints in my workload?

This blog post has moved to
http://blogs.oracle.com/optimizer/entry/what_should_i_do_with_old_hints_in_my_workload

Maria Colgan

Oracle Open World 2009 Summary

We had a great time talking to our users at Open World 2009 both at our Demogrounds booth and at our two sessions. We received a lot of interesting questions during the Optimizer Roundtable discussion, but we did not get to answer all of them due to time constraints. We plan to address the questions we received (both answered and unanswered) in future blog posts... so stay tuned. If you didn't get to attend the discussion, but have a question about the Optimizer, submit it through the email link above.

For those of you who did not get a chance to stop by our Demogrounds booth, here's a recap of the new features that we talked about. Many of the topics have already been covered in earlier blog posts.

• Enhanced bind peeking with Adaptive Cursor Sharing: Read about Adaptive Cursor Sharing and a followup.


• Faster and more accurate Statistics gathering: Read about our new statistics gathering algorithm in 11g and incremental maintenance of global statistics for partitioned tables.


• New types of Statistics that improve cardinality estimates


• Ability to gather but not publish Statistics


• Guaranteed plan stability and controlled plan evolution: Read about SQL Plan Management.


• New tools to help correct regressed execution plans: Read about our Plan Diff tool and Test Case Builder.

These topics are focused on well-known pain points from earlier versions of Oracle. But we also have plenty of new optimizations in Oracle 11gR1 and 11gR2. Stay tuned for details about some of our new optimizations.

Maria Colgan

Open World Recap and New White papers

The Optimizer group has two session and a demo station in the Database campground at this year's Oracle Open World. We will give a technical presentation on What to Expect from the Oracle Optimizer When Upgrading to Oracle Database 11g and host an Oracle Optimizer Roundtable.

The technical session, which is on Tuesday Oct 13 at 2:30 pm, gives step by step instructions on how to use the new 11g features to ensure your upgrade goes smoothly and without any SQL plan regressions. This session is based on our latest white papers, Upgrading from Oracle Database 10g to 11g: What to expect from the Optimizer and SQL Plan Management in Oracle Database 11g.

The roundtable, which is on Thursday Oct. 15th at 10:30 am, will give you a first hand opportunity to pose you burning Optimizer and statistics questions directly to a panel of our leading Optimizer developers. In fact if you plan to attend the roundtable and already know what questions you would like to ask, then please send them to us via email and we will be sure to include them. Other wise, you can hand in your questions at our demo station at any stage during the week, or as you enter the actual session. Just be sure to write your questions in clear block capitals!

We look forward to see you all at Open world.

Maria Colgan

What's Changed between my New Query Plan and the Old One?

This blog post has moved here
http://blogs.oracle.com/optimizer/entry/whats_changed_between_my_new_query_plan_and_the_old_one