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How To Troubleshoot OEM 12c Cloud Control Auto-Discovery

I was recently involved with an upgrade project to go from 11.2.0.2 to 11.2.0.3 on an Exadata V2. We hit some snags during the upgrade specifically related to OEM 12c Cloud Control. We performed an out-of-place upgrade and OEM 12.1.0.1.0 had some difficulty in dealing with this.

12c Cloud Control is supposed to run a daily check which looks for new targets on each server. When it finds something new, it places this in a queue to wait for admin approval. With a single click you can promote the newly discovered target into an OEM managed object.

STS, OFE and SPM

That’s SQL Tuning Sets, optimizer_features_enable, and SQL Plan Management.

There’s a recent post on OTN describing an issue when using SQL Tuning Sets to enforce plan stability when upgrading from 10.2.0.3 to 11.2.0.3 – it doesn’t always work. Here’s a very simple model to demonstrate the type of thing that can happen (the tables are cloned from a completely different demo, so don’t ask why I picked the data they hold):

Optimisation ?

I was at a client site recently where one of the end-users seemed to have discovered a cunning strategy for optimising a critical SQL statement. His problem was that his query screen times out after 2 minutes, so any query he runs has to complete in less than two minutes or he doesn’t see the results. Unfortunately he had a particular query which took nearly 32 minutes from cold to complete – partly because it’s a seven-table join using ANSI OUTER joins, against tables ranging through the 10s of millions of rows and gigabytes of data – the (necessary) tablescan of the table that had to be first in the join order took 70 seconds alone.

Session Snapper v4 – The World’s Most Advanced Oracle Troubleshooting Script! – Webinar

Snapper V4 Webinar

Catchy title, huh? :-)

The Snapper v4 is getting ready! I am going to launch it on Wednesday 13 Feb 11am PST at the Snapper V4 webinar (register here).

The major new features include:

  1. RAC support – ability to query stats from remote instances
  2. Manual Before and After snapshot support – no need to use DBMS_LOCK sleeps anymore
  3. Show useful averages and ratios *in addition to* raw metrics for faster troubleshooting
  4. And more! :)

Snapper is still a free-to-use tool and it still does NOT require any object creation nor changes in your databases for use. Now even DBMS_LOCK access isn’t needed, although it’s still useful for convenience.

Diagnosing ASMlib

To use ASMlib or not to use ASMlib? That is the question. Or at least, that is a question that frequently crops up when I'm on consulting engagements with customers. I have personally changed my mind a couple of times on this exact question, and I'm currently sat with one leg on either side of […]

Diagnosing ASMlib

To use ASMlib or not to use ASMlib? That is the question. Or at least, that is a question that frequently crops up when I'm on consulting engagements with customers. I have personally changed my mind a couple of times on this exact question, and I'm currently sat with one leg on either side of […]

Understanding Oracle Optimizer Statistics Webinar Q&A

There were quite a few questions asked during the webinar yesterday that I didn't have time to answer online. So, here's the list of questions from the webinar transcripts with my answers. In some cases, I combined several similar questions and gave a single answer. Hope it's helpful!

1. Can you give your thoughts on bind peeking and how this relates to statistics?

Delphix

If you’re a regular follower or my blog you may recall Kyle Hailey and the joint webinar we did nearly two years ago on “Visual SQL Tuning” covering an approach I’ve written about in the past and a product that he developed at Embarcadero to automate the work that I’d been doing by hand and eye.

Understanding Oracle Optimizer Statistics Webinar Follow-up

Thanks to everyone for attending today's webinar on Understanding Oracle Optimizer Statistics sponsored by Embarcadero Technologies. I appreciate everyone who took time to join me today and hope you found it informative.

The webinar recording will be posted within in the next couple of days, but you can download the presentation file now.

Understanding Oracle Optimizer Statistics - presentation

I'll provide the link to the recording as soon as it's available and will update this post with Q&A from the webinar sessions shortly.

Thanks and again and see you in March when I'll be presenting "Back to the Future: Oracle SQL Performance Firefighting using AWR."

Enkitec Extreme Exadata Expo (E4) 2013 – Call for Papers

Enkitec E4, the only exclusively Exadata-focused conference in the world, is going to be back this this year too! :-)

It will take place on 5-6 August 2013 in Four Seasons Hotel & Resorts in Irving, TX. It will be very hot in Texas then, but the hotel has a really cool pool there (which I intend to be able to use this year – last year I had to spend all my free time working in the hotelroom unfortunately). And they have beer inside too :)

There will be very good speakers showing up this year too (including the keynote speaker who’s awesome, but I can’t say the name yet) and I’ll hang out there too. I think I’ll deliver a live demo / internals hacking session this year (that way I don’t have to spend my night before the conference preparing slides and can focus more on the cool stuff).