Wednesday Jan 09, 2013

How does SQL Plan Management match SQL statements to SQL plan baselines?

Happy New Year to all of our readers!

As more and more of your systems migrate to Oracle Database 11g, SQL Plan Management (SPM) is becoming increasingly popular as a mechanism to maintain plan stability and subsequently system performance. However, one of the key frustrations folks encounter when using SPM is that the SQL plan baseline they painstakingly created is not used.

[Read More]

Wednesday Nov 21, 2012

How do I create statistics to make ‘small’ objects appear ‘large’ to the Optmizer?

I recently spoke with a customer who has a development environment that is a tiny fraction of the size of their production environment. His team has been tasked with identifying problem SQL statements in this development environment before new code is released into production.

The problem is the objects in the development environment are so small, the execution plans selected in the development environment rarely reflects what actually happens in production.

[Read More]

Thursday Oct 04, 2012

Day 5 of Oracle OpenWorld 2012 October 4th

Its the last day of Oracle OpenWorld and we have saved the very best for last. So hopefully you are still awake and functioning at this stage!

Today, we present An Insider’s View of How the Optimizer Works (Session CON8457) at Moscone South - room 104. This session explains how the latest version of the optimizer works and the best ways you can influence its decisions to ensure you get optimal execution every time

We really hope you have enjoy the conference so far and will stop by our session this afternoon before you head off home!

Wednesday Oct 03, 2012

Day 4 of Oracle OpenWorld 2012 October 3rd

Thanks to all those who stopped by the demogrounds  to chat with the Optimizer developers and to check out what is new in the Oracle Optimizer over the last two days. Remember, today is the last day of the demogrounds, so if you haven't had a chance to stop by and collect you bumper sticker yet, do so today. The Optimizer developers will be there from 9:45 am until 4pm.

Don't forget our second technical session (Session CON8457) is tomorrow at 12:45pm.

Tuesday Oct 02, 2012

Day 3 of Oracle OpenWorld 2012 October 2nd

Hopefully you enjoyed yesterday, the first full day of technical sessions at Oracle OpenWorld and are ready for more today!

Today we give our first technical session, Oracle Optimizer: Harnessing the Power of Optimizer Hints (Session CON8455) at 1:15pm, in Moscone South - room 103. In this session we will discuss in detail how Optimizer hints are interpreted, when they should be used, why they appear to be ignored and what you can do if you have inherited a hint ridden application.

The Optimizer team will also be at the Oracle Database Demogrounds all day.  Demogrounds open at 9:45 am and run until 6pm. So stop by and find out what's new with the Optimizer and the statistics that feed it. Don't forget to pick up your Optimizer bumper sticker while you are there!

Monday Oct 01, 2012

Day 2 of Oracle OpenWorld 2012 October 1st

Oracle OpenWorld started yesterday and San Francisco is just buzzing with Oracle folks! If you are attending the conference don't miss the opportunity to chat with the Optimizer development team at one of our technical sessions or at the Oracle Demo grounds.

Our first technical session(Session CON8455) happens tomorrow at 1:15pm but the Oracle Optimizer Demo booth opens today. We are located in the database demo grounds, in Moscone South, booth number 3157.

Members of the Optimizer team will be available from 9:30am to 6pm today, to answer any Optimizer questions you might have and of course to dole out our limited edition Optimizer bumper stickers! The must have souvenir from this years conference

+Maria Colgan

Sunday Sep 30, 2012

Day 1 of Oracle OpenWorld 2012 September 30

Howard Street in San Francisco is closed. The large Oracle tent is up! Attendees are arriving by the plane load at SFO. It can only mean one thing ....

That's right!  Oracle OpenWorld officially starts today with the Oracle Users Forum. Ton's of great technical sessions selected by the Oracle User Groups get under way this morning at 8 am (Doh!). And of course, Larry's keynote is this evening 5:00 pm–7:00 pm, Moscone North. A must see, as he is bound to make some exciting announcements to get the show started!

Hope to see ya there!

Monday Sep 17, 2012

More on Oracle OpenWorld 2012

With only two weeks to go until Oracle OpenWorld, it is time to start planning your schedule. Every year folks ask me what Optimizer related sessions they should go and see at OpenWorld. Below are my top two picks for each day of the conference, to get your schedule started. .[Read More]

Wednesday Sep 05, 2012

Oracle OpenWorld 2012

I can't believe it's time for OpenWorld again!

Oracle OpenWorld is the largest gathering of Oracle customers, partners, developers, and technology enthusiasts. This year it will take place between September 30th and October 4th in San Francisco. Of course, the Optimizer development group will be there and you will have multiple opportunities to meet the team, in one of our technical sessions, or at the Oracle Database demogrounds.

[Read More]

Wednesday Aug 29, 2012

How do I restrict concurrent statistics gathering to a small set of tables from a single schema?

I got an interesting question from one of my colleagues in the performance team last week about how to restrict a concurrent statistics gather to a small subset of tables from one schema, rather than the entire schema. I thought I would share the solution we came up with because it was rather elegant, and took advantage of concurrent statistics gathering, incremental statistics, and the not so well known “obj_filter_list” parameter in DBMS_STATS.GATHER_SCHEMA_STATS procedure.

[Read More]

Friday Jul 13, 2012

Upcoming events: INOUG Oracle Training Day!

The Indiana Oracle User Group (INOUG) have been kind enough to ask me to present an all day Optimizer workshop at their annual training day on July 26th at Eli Lilly & Co. The workshop will consist of four 90 minute session and will explain the fundamentals of the cost based Optimizer and the statistics that feed it, as well as providing a methodology for diagnosing and resolving SQL execution performance problems.

The workshop begins with an in-depth look at statistics and statistics maintenance, a challenge all DBAs must face in order to prevent suboptimal execution plans. It continues with a detailed explanation on how to interpret an execution plan. Each aspect of an execution plan will be examined, from cardinality estimates to parallel execution, and you will learn what information you should be gleam from the plan and how it affects the execution performance of a SQL statement. After lunch the workshop focuses on the process of analyzing and resolving the most common SQL execution performance problems including poor cardinality estimations, bind peeking issues, selecting the wrong access method and much, much more.

You can register for the event here. I hope you can join us!

+Maria Colgan

Thursday Jul 05, 2012

How do I cut and paste commands from your blog?

At the recent ODTUG  Kscope 12 conference several people told me that they really enjoyed our blog on the Optimizer but were frustrated because they couldn’t cut and paste the commands used in the blog posts straight into their environment.

Typically I use screen shots in the blog posts to make the commands clear but it does mean that it is impossible to cut and paste the commands into your environment. In order to get around this I have created a downloadable .sql script for each of our blog posts. You should now see the sentence “You can get a copy of the script I used to generate this post here”, appearing at the bottom of each blog post. Clicking on the link will open the .sql script that contains all of the commands used in the post. You can either save the entire script or just cut and paste the particular command you are interested in!

I have added scripts for all of this year’s blog posts and am slowly making my way through our old posts until we have a script for everything we have posted to date.

Hopefully this will help!

+Maria Colgan

[Read More]

Monday Jul 02, 2012

We have a winner!

Thank you all for voting for your favorite Optimizer bumper sticker slogans. We are proud to announce we have a winner! With over 40% of the votes, "Proud parent of a child cursor"  will be the official Optimizer bumper sticker at this year's Oracle Open World!


Don't forget you will be able to pickup your Optimizer bumper sticker at the Optimizer demo booth in the Oracle demo grounds!

Looking forward to seeing you there!

+Maria Colgan

[Read More]

Monday Jun 25, 2012

Last chance to vote in Optimizer Bumper Sticker Competition

There is still time to vote in our competition to find the best Optimizer bumper sticker, which we will give away at the Optimizer demo booth at this years Oracle Open World.

Click here to vote for your favorite. Then stop by the Optimizer demo booth at Oracle Open World to claim your bumper sticker!

Remember voting will close on June 30th and the winning slogan will be announced in early July.

+Maria Colgan

Saturday Jun 09, 2012

Optimizer Bumper Sticker Competition

For the last couple of months we have been running a competition on twitter (@SQLMaria) looking for the best Optimizer bumper sticker, which we will give away at the Optimizer demo booth at this years Oracle Open World. We got tons of excellent entries and had a tough time narrowing it down to just 5 but we have. So now we need your help to pick the final winner. Click here to vote for your favorite. Then stop by the Optimizer demo booth at Oracle Open World to claim your bumper sticker!

[Read More]
About

The Oracle Optimizer blog is written by members of the Optimizer development team. The goal of this blog is to provide an insight into the workings of the Optimizer and the statistics it relies on. The views expressed on this blog are our own and do not necessarily reflect the views of Oracle and its affiliates. The views and opinions expressed by visitors on this blog are theirs solely and may not reflect ours.

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