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June 2012

Little things worth knowing-static and dynamic listener registration

As part of  a recent project to remove a vulnerability in relation to CVE-2012-1675 it became apparent that there are certain misconceptions around dynamic and static listener registration which are hard to get rid of. The below is applicable for single instance Oracle only!

Now let’s start with a quiz: what does the following output imply:

Oracle, Proxy, Obfuscation, Cookie Law, Talks, more...

It has been a long while since my last blog post. I have been very busy with Oracle security consulting, data security audits, teaching training courses and of course with my companies Database Security Scanner - PFCLScan . Oracle security....[Read More]

Posted by Pete On 20/06/12 At 02:23 PM

Linux 6 Transparent Huge Pages and Hadoop Workloads

This past week I spent some time setting up and running various Hadoop workloads on my CDH cluster. After some Hadoop jobs had been running for several minutes, I noticed something quite alarming — the system CPU percentages where extremely high.

Platform Details

This cluster is comprised of 2s8c16t Xeon L5630 nodes with 96 GB of RAM running CentOS Linux 6.2 with java 1.6.0_30. The details of those are:

Pascal matrix SQL puzzle solution

I’ve been impressed with the solutions to my little problem of generating a symmetric Pascal matrix using SQL. Charles Hooper in particular has provided some very nice commentary on the problem, complete with diagrams and 2 alternative solutions.

I thought I’d walk through my solution in order to explain my thought process and see if it resonates with anyone.

Usually when I think about generating rows with SQL I think about the Oracle “trick” of using the CONNECT BY clause to generate rows:

select level from dual connect by level <= k

You’ll see a lot of constructs like this in the solutions provided by commenters.

However, lately I’ve been tending more toward the ANSI SQL Recursive construct instead, which works in Oracle and many other SQL databases:

East Coast Oracle Users Group Conference...

I'll be speaking at the East Coast Oracle Users Group Conference held in North Carolina on October 16th-18th.  It is always nice to be able to stay in my own timezone for a change!

There are opportunities to not only attend the conference but also to speak - they are still accepting abstracts for presentations until June 21st.  If you have done anything interesting (you have), please consider speaking out about it.  Others will be interested.  You never know how it will go unless you try!

Hope to see you there!

How do people prototype their quantitiative visualizations

Been a while since I blogged. There are a lot of things in the works but they involve a fair bit of scripting, thus I’m spending more time smoothing out the rough edges before I blog them. Projects include

June 2012: Jonathan Lewis is coming to Dallas

Quick note about Jonathan Lewis trip to Dallas: Jonathan Lewis will be presenting two day seminar on two topics, “Beating the Oracle Optimizer” (June 28) and “Troubleshooting and tuning” (June 29th).

The event will be held June 28-29, 2012 at SMU-in-Legacy in Plano, TX.

This is a must-attend event for experienced DBAs and Developers. Especially, if you are planning to upgrade your database/application in the near-future or if you are in the middle of an upgrade, you must attend these two seminars. This seminar series provide enormous value resolving complex Production performance issues.

Click Here for details.

Friday Philosophy – Presenting Leads to Drinking, Discuss

Just a quick Friday Philosophy {the day job is very demanding at the moment, thus the silence on the Blog front}

I’m presenting in Leeds at the start of July on UKOUG AIM SIG on “The First Few Things You Need To Know About Exadata”. As part of the final preparation of the agenda it’s been raised that we should have a beer after the event and put it on the agenda.

Now, when I ran the Management and Infrastructure SIG, there was always a last item of “retire to a pub for a drink or two”. It is a common feature of technical UKOUG SIGs and a great opportunity to chat to the speakers more.