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September 2012

Oracle Open World 2012 – Oracle XML DB Presentations and Hands-on Labs

I hereby am following up on a small tradition, that I think I get going since 2006…An agenda overview of all things XMLDB you can do or see during this years Oracle Open World. Oracle Open World is the biggest IT conference nowadays in the world with 40.000+ thousand attendees and 1600+ sessions or workshops,

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Online Rebuild

I’ve commented in the past about the strange stories you can find on the internet about how Oracle works and how sometimes, no matter how daft those stories seem, there might be something behind them. Here’s one such remark I came across a little while ago – published in two or three places this year:

“An index that enforces referential integrity cannot be rebuilt online.”

Making SQL Performance Solutions Stick - Followup #2

During last week's webinar, there were several questions that I did not have a chance to answer so I wanted to follow-up by answering those questions here. I also wanted to provide links to previous webinar recordings as many people had asked where to find them.

Webinar Recordings
Best Practices for Developing Optimally Performing SQL

Diagnosing SQL Performance Problems (Part 1 of 3 part series)

Enkitec Extreme Exadata Expo

(Otherwise known as #E4)

Another late post, but a few weeks ago I had the pleasure of attending and speaking at Enkitec's dedicated Exadata conference, E4. The stand-out impressions that I've been babbling away to people about since getting home were :-

1) The uniformly good quality of the presentations I was able to attend. It was an excellent agenda and speakers.

2) The great organisation, particularly for Enkitec's first attempt at this. In particular they took very good care of the speakers.

3) The small but very informed and friendly group of attendees. It's often the case that the smaller conferences feel the best because of the more relaxed atmosphere and extra interaction

4) The heat! Although the air conditioning obviously helped.

New Oracle Security Talks

I am going to be doing three sessions at the UKOUG conference this December in Birmingham. I am going to be chairing the Oracle Security Round table on the 4th December. I am also writing three new presentations; two for....[Read More]

Posted by Pete On 04/09/12 At 02:44 PM

Optimizer statistics-driven direct path read decision for full table scans (_direct_read_decision_statistics_driven)

Hello all fellow Oracle geeks and technology enthusiasts! Long time no see ;-)

In the hacking session about Oracle full table scans and direct path reads I explained how the direct path read decision is not done by the optimizer, but instead during every execution, separately for every single segment (partition) scanned in the query. I also explained how the _small_table_threshold parameter and the X$KCBOQH.NUM_BUF(which keeps track of how many buffers of any segment are currently cached) are used for determining whether to scan using direct path reads or not.

Optimizer statistics-driven direct path read decision for full table scans (_direct_read_decision_statistics_driven)

Hello all fellow Oracle geeks and technology enthusiasts! Long time no see ;-)
In the hacking session about Oracle full table scans and direct path reads I explained how the direct path read decision is not done by the optimizer, but instead during every execution, separately for every single segment (partition) scanned in the query. I also explained how the __small_table_threshold_ parameter and the X$KCBOQH.NUM_BUF(which keeps track of how many buffers of any segment are currently cached) are used for determining whether to scan using direct path reads or not.

Optimizer statistics-driven direct path read decision for full table scans (_direct_read_decision_statistics_driven)

Hello all fellow Oracle geeks and technology enthusiasts! Long time no see ;-)
In the hacking session about Oracle full table scans and direct path reads I explained how the direct path read decision is not done by the optimizer, but instead during every execution, separately for every single segment (partition) scanned in the query. I also explained how the __small_table_threshold_ parameter and the X$KCBOQH.NUM_BUF(which keeps track of how many buffers of any segment are currently cached) are used for determining whether to scan using direct path reads or not.

New Oracle Security Presentation - Identity In The Database

The paper " Identifying Yourself in the Oracle Database " is available as a pdf to download from my Oracle security white papers page . This is new paper in terms of it has not been posted to my site....[Read More]

Posted by Pete On 03/09/12 At 08:11 PM

On the Topic of Programming 3

September 3, 2012 (Back to the Previous Post in the Series) In the previous article in this series, a question was posed regarding how many SQL statements would be required to generate the following report, which displays in Microsoft Excel: A significant number of items regarding the report require explanation: Employee IDs and employee names [...]