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December 2012

Oracle and the ‘kfk: async disk IO’ wait event

Recently I was discussing some IO related waits with some friends. The wait I was discussing was ‘kfk: async disk IO’. This wait was always visible in Oracle version and seems to be gone in version and above. Here is the result of some investigation into that.

First: the wait is not gone with version and above, which is very simple to prove (this is a database version

Happy Holidays

For all those that are in the midst of some form of religious, seasonal or statutory holiday at the moment, I hope it goes well for you. :)

I promised myself I would forget about work for the next couple of weeks and just play with technology, but I’ve already logged in to check the backups etc. What a dope. :)

Wishing you all a happy holiday and a productive new year!





Updated 22nd Jan
I’ve previously advertised the fact that the latest online discussion that Red Gate has arranged for me to have with Grant Fritchey will be on 23rd Jan and we will be talking about statistics. If you’ve listened in to any of these talks in the past you’ll realise that they are completely unscripted; what you get is a couple of guys in a (virtual) pub comparing and contrasting their favourite database engines and trying to learn a little bit about how the other technology works.

Merry Christmas and A Happy New Year !! (The Snowman)

I just like to wish you all a very Merry Christmas and a Happy, Index-Rebuild Free New Year !! I have a feeling next year will very exciting one for Oracle Database professionals:) My little “gift” this year is a lovely little animation called “The Snowman” that dates all the way back to 1982 when I arrived […]

Updated Presentations Section

Just a quick note to let you know that I updated the presentations section of my blog. Most of the talks I’ve done over the last 3 years, including Hotsos Symposium, RMOUG Training Days, Oracle Open World, UKOUG Conference and Enkitec Extreme Exadata Expo (E4) are now on the site.

Oracle GoldenGate Sequence Replication

When using Oracle GoldenGate sequence replication there is a number of issues you need to be aware of especially if you replicate quite a lot of busy sequences.

The first issue is that GoldenGate sequence replication does not use bind variables. Let's execute the following statements on the source system:

SQL> create sequence rep1.s1 nocache;

Sequence created

SQL> select rep1.s1.nextval from dual;


SQL> select rep1.s1.nextval from dual;


GoldenGate uses PL/SQL procedure called replicateSequence each time it needs to sync sequence values. The following calls will be made on the destination system as a result of the above statements:

BEGIN ggext .replicateSequence (TO_NUMBER(2), TO_NUMBER(20), TO_NUMBER(1), 'REP1', TO_NUMBER(0), 'S1', UPPER('ggrep'), TO_NUMBER(1), TO_NUMBER (0), ''); END;


The evaluations for UKOUG 2012 are in – though perhaps not all of them have been loaded into the “Speaker Lounge” yet. I’m fairly pleased with my scores.  On a range of 1 – 6:

Presentation skills: 5.8, 5.79, and 5.72

Of course I have to say that great presentation skills don’t necessarily mean that the presentation was good. I’ve seen a couple of presentations in the past where the presenter was brilliant at communicating his topic – unfortunately at least half of what he  said was wrong. Conversely I’ve sat through a few presentations where the material was brilliant, but the presenter just needed lots more practice.

Fortunately I think the following scores show that it wasn’t all show and no substance:

Content Evaluation: 5.56, 5.36, 5.28

No DBA is an Island


I gave an OakTalk at the UKOUG2012 conference. This article is based upon the notes for that talk. It is not a technical article, just an opinion piece.
I have always described myself as a DBA, although it has been many years since I had day-to-day responsibility for a production database.  My day job is about performance, helping people to get the best possible performance from their PeopleSoft systems.  That can involve anything from tuning a specific SQL statement, to changing how the database, middleware, or application has been configured, through to standing back and looking at the way the architecture has been put together.  Lots of people have to work together on any system, and I frequently work with people for whom the database is not their home

UKOUG Speaker Evaluations…

This is a bit of a vanity post, so excuse me blowing my own trumpet.

I just took a look at the speaker evaluation feedback from UKOUG 2012 and it was pretty good. Only 4 of the people left “wordy” feedback:

  • Could have done with more time. Just the sort of presentation I came to conference for v.good.
  • Impressive.
  • Brilliant presenter and useful content, could have been twice as long.
  • Very nice presentation.

As far as the rating feedback went, the scores in each area were out of 6. I got just under 5 for the slides and the rest (content, presentation skills and value of presentation) were all above 5, which I think is pretty good. I was particularly happy with the presentation skills result.

I don’t take this stuff too seriously as these ratings are very subjective. Some people are always mega-critical and some people would give you 6/6 if you tripped and fell of the stage, but it is a nice little ego boost.

HOWTO: Viewing XML data in V_$CELL_% storage cell SYS views

Got a small question from Frits if I could help him make some XML data readable in one of the SYS.V_$CELL_% / V$CELL_% views. I have been a bit busy, in between jobs, to try to make some of those XML columns more readable anyway (for myself and others) so…lets have a go at it. …

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