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October 2013

Parallel Execution – 2

Since I’m going to write a couple of articles dissecting parallel execution plans, I thought I’d put up a reference post describing the set of tables I used to generate the plan, and the query (with serial execution plan) that I’ll be looking at. The setup is a simple star schema arrangement – which I’ve generated by created by creating three identical tables and then doing a Cartesian join across the three of them.

WebLogic 11g, Forms, ADF, Oracle Linux and VMware

Following on from my recent batch of “what I’m doing at the moment” style posts, I just thought I would mention some of the infrastructure I’ve been installing and configuring recently…

We are still part way through a migration from Oracle Application Server to WebLogic 11g. There are many applications to migrate and test, fortunately not by me, but they fit into two main categories.

Transcript of the interview with Jonathan Lewis

If you missed the interview with Jonathan Lewis or don’t want to spend 93 minutes watching it, here is its transcript. Thanks to Stanislav Osekin from Innova, who did most of the hard work. I have only corrected special Oracle terms. Also thanks to Jonathan, who helped me in several complex cases where I couldn’t understand the wording.

T: Hello and welcome! My name is Timur Akhmadeev and I’m sitting here at the Innova office with Jonathan Lewis. Hello, Jonathan!

J: Morning, Timur! Nice to be here!

T: Nice to see you too! Thank you for coming!

J: My pleasure!

The Exadata wait event ‘cell smart table scan’

The purpose of this post is to show what the wait event ‘cell smart table scan’ means, based on reproducible investigation methods.

First of all, if you see the ‘cell smart table scan’ event: congratulations! This means you are using your exadata how it’s intended to be used, which means your full table scan is offloaded to the cells (storage layer), and potentially all kinds of optimisations are happening, like column filtering, predicate filtering, storage indexing, etc.

But what is exactly happening when you see the wait event ‘cell smart table scan’? Can we say anything based on this waits, like you can with other wait events?

Control Charts

Last week, while working on customer engagement, I learned a new method of quantifying behavior of time-series data. The method is called “Control Chart” and credit to Josh Wills, our director of data science, for pointing it out. I thought I’ll share it with my readers as its easy to understand, easy to implement, flexible and very useful in many situations.

The problem is ages old – you collect measurements over time and want to know when your measurements indicate abnormal behavior. “Abnormal” is not well defined, and thats on purpose – we want our method to be flexible enough to match what you define as an issue.

For example, lets say Facebook are interested in tracking usage trend for each user, catching those with decreasing use

There are few steps to the Control Chart method:

Parallel Execution – 1

When you read an execution plan you’re probably trying to identify the steps that Oracle went through to acquire the final result set so that you can decide whether or not there is a more efficient way of getting the same result.

Bernie Dugggs - 8bit Oak Roots

Media: 
See video

Bernie Dugggs Oak Table Sunday 2012 presentation taking a nostalgic look at developing games for the ZX Spectrum and how some principles don't change. Original abstract ....

8-Bit Oak Roots
"There's a reason so many Oakies are about the same age. We were the keen users of the first popular computers. The British version of that experience was based on cheap and available 8-bit home computers that unleashed people's latent passion, talent and ingenuity in over-coming platform limitations.
Bernie Dugggs will take a nostalgic look at his personal history as a developer of commercial ZX Spectrum computer games for Imagine, Ocean and Odin and show how relevant the experiences and lessons learned have remained throughout a career in software"

Bernie Dugggs - 8bit Oak Roots

Media: 
See video

Bernie Dugggs Oak Table Sunday 2012 presentation taking a nostalgic look at developing games for the ZX Spectrum and how some principles don't change. Original abstract ....

8-Bit Oak Roots
"There's a reason so many Oakies are about the same age. We were the keen users of the first popular computers. The British version of that experience was based on cheap and available 8-bit home computers that unleashed people's latent passion, talent and ingenuity in over-coming platform limitations.
Bernie Dugggs will take a nostalgic look at his personal history as a developer of commercial ZX Spectrum computer games for Imagine, Ocean and Odin and show how relevant the experiences and lessons learned have remained throughout a career in software"

OTN Nordic Tour 2013

I’ll be representing the Oracle ACE Program as part of the OTN Nordic Tour this year. I’ve just booked my flights, so in a little over a week I’ll be starting the three date tour.

  • Oct 22nd : Stockholm, Sweden (ORCAN) – 3 Presentations
  • Oct 23rd : Copenhagen, Denmark (DOUG) – 2 Presentations
  • Oct 24th : Oslo, Norway (OUGN) – 2 Presentations

I put forward a few different papers each event picked different ones, so it looks like I could be presenting up to 6 distinct sessions over the tour. This next week is going to be very busy. I’ve got to put the finishing touches to one presentation, then rehearse all 6 a few times… :)

Cheers

Tim…

OpenLDAP – Using phpldapadmin to Maintain your LDAP Server

This is the final part of a multi-part blog post on using OpenLDAP for Net Service Name Resolution.  Part 1 can be found here.

Ok, now that you have installed and configured phpldapadmin, you’ll want to do some customization, that will facilitate using phpldapadmin specifically for maintaining Net Service Names.  Remember, phpldapadmin is a generic tool, that can be used to manage any LDAP server, with virtually any type of content.  At this point, you can use it to manage your LDAP server, but, I’ll provide you two new custom templates, for managing Net Service Names and Net Service Aliases.

Basic phpldapadmin Navigation