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Auditing for Physical Standby Databases with Real-Time Query

Veröffentlicht von Uwe Hesse in TOI am März 28, 2012

Today I got asked by a colleague whether we can do auditing on a Physical Standby that does Real-Time Query. My response was: Probably yes, with AUDIT_TRAIL=OS for the Standby and the audit command specified on the Primary. I did just test that and it really works this way! There is no need to have the AUDIT_TRAIL parameter value different from NONE on the Primary even. Just call a command like

SQL> audit session whenever not successful;

on the Primary and it will reach the Physical Standby via Redo-Apply. I tested that with

SQL> select * from v$version;

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production
PL/SQL Release 11.2.0.3.0 - Production
CORE    11.2.0.3.0    Production
TNS for Linux: Version 11.2.0.3.0 - Production
NLSRTL Version 11.2.0.3.0 - Production

but I suppose it will work the same with lower versions. But then: „Don’t believe it, test it!“ 🙂

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OUGN Spring Seminar Day 3

Veröffentlicht von Uwe Hesse in TOI am März 25, 2012

 Writing this while waiting at the airport for my flight to Stockholm. There was no time for this before although the event already ended on Saturday morning.

On the last day of the OUGN Spring Seminar, I attended again Jonathan Lewis with his presentation about „Key Features of Redo“. He started with a great introduction into the Oracle Database Architecture, followed by a deeper dive into Redo. Some of the technical details are here, while almost everything about the presentation can be found in the second chapter of his new book.

My own presentation at this event was about Real-Time Query and can be found here. I got some really nice feedback from attendees, so it was probably not a complete disaster…

Finally, I saw my colleague Harald van Breederode presenting about Client Connectivity in a Data Guard environment. He was indeed as good as I expected 🙂

In summary, I was very pleased with the whole event: Great job, OUGN!

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OUGN Spring Seminar Day 2

Veröffentlicht von Uwe Hesse in TOI am März 22, 2012

We are actually now on the cruise ship! I am not going to put any pictures into this posting, because the WLAN here is very slow and the upload would take forever therefore. The first session I attended today was held by Jonathan Lewis about „Design Optimal SQL“. It was very interesting and well presented – almost the whole presentation is here.

Next came Doug Burns with „Performance and Stability with Oracle 11g SQL Plan Management“. I was curious to see how he would approach that topic that was covered by Maria Colgan yesterday already. It turned out that he emphasized his Real World (TM) experiences with that feature rather than explaining it again – in a very entertaining fashion, I may add 🙂

Some key points for me were:

  • SQL Plan Baselines are very useful and easy to implement.
  • After an upgrade to 11g, typically a few statements will show a degraded performance. These get the most attention although the majority of statements stays with the same performance or improves.
  • Collecting SQL Plan Baselines on Test Systems and deploying them (via staging tables) to Production Systems works very well and „we do it all the time“.
  • Setting of OPTIMIZER_FEATURES_ENABLE=10.2.0.4 indeed returned the optimizer behavior of the previous release – that is in line with Maria’s claim yesterday about that parameter.
  • Now collecting SQL Plan Baselines for these statements will first only allow the good old 10g plans with the chance to get new better plans evolved later.
  • Evolvement is not as much in the focus for customers than Plan Stability.

Next I attended again Maria Colgan with „Understanding and Managing Optimizer Statistics“. Again I knew most of the technical aspects she presented (e.g. the option that we can set statistic preferences instead of having to rewrite the statistic collection completely, but got some interesting background information. She recommended strongly to use the (greatly improved) AUTO_SAMPLE_SIZE that now works much better than in 10g. It is as fast as a 10% sampling but nearly as accurate as a 100% sample size. Maria reported about a guy from our Real World Performance Group who wanted to prove this claim wrong but had to admit (after 2 weeks of trying to falsificate) that it is indeed as good and they now use it with their systems as well 🙂

So much for today. Tomorrow will be my own presentation about Real-Time Query. I’m a bit excited about it – never did that on a ship yet 🙂

 

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