|
Home
Page
Back to Papers |
Please note this page has moved to http://oracledoug.com/px10.html. You will be redirected in 5 seconds but it would be better to update your bookmarks ;-) Other Resources The best source of information on Parallel Execution is the Oracle documentation. It's amazing how often I find the (free) manuals far superior to (paid-for) 3rd party books! Specifically, the Data Warehousing Guide contains a couple of relevant chapters :- There are also a number of useful resources on Metalink, including a specific section containing the most useful notes that you can access by selecting 'Top Tech Docs', 'Database', 'Performance and Scalability' and then ‘Parallel Execution’ from your Metalink home page. The following documents are particularly relevant to this paper.
184417 – Where to track down the information on Parallel Execution in the Oracle documentation!
203238 – Summary of how Parallel Execution works.
280939 - Checklist for Performance Problems with Parallel Execution (but also contains a useful explanation of DFO effects on number of PX slaves used)
119103 – Parallel Execution Wait Events (contains links to event-specific information)
201799 – init.ora parameters for Parallel Execution
240762 – pqstat PL/SQL procedure to help monitor all of the PX slaves running on the instance or for one user session
202219 – Script to map PX slaves to Query Co-ordinator (An alternative to using the procedure in note 240762.1)
275240 – Discusses Bug no. 2533038 in the Parallel Adaptive Multi-User algorithm (fixed in 9.2.0.3) which makes it sensitive to idle sessions, leading to an under-utilised system.
238680 – Investigating ORA-4031 errors caused by lack of memory for queues.
242374 – Discusses some of the issues around PX session tracing (but not in any great depth)
237328 – Direct Path Reads (brief discussion)
Bibliography The following books contain some useful information about Parallel Execution. Oracle SQL High Performance Tuning. - Harrison, Guy - Prentice Hall Effective Oracle by Design. - Kyte, Thomas - Oracle Press Practical Oracle 8i – Building Efficient Databases. - Lewis, Jonathan - Addison Wesley Oracle Parallel Processing. - Mahapatra,Tushar and Mishra Sanjay - O’Reilly & Associates, Inc. There’s also an excellent Parallel Execution conference paper by Jeff Maresh. As well as covering server configuration it contains more developer-orientated information about using PX within your application than I’ve covered in this document. And, as usual Jonathan Lewis has some previous articles on this subject! Although these are geared to Oracle 7.3, much of the content makes sense across versions. Finally, here’s a nice PX slave monitoring query from the “Co-operative Oracle Users’ FAQ” Acknowledgements There were many people who contributed to this article to make it a lot better than it was originally, pointing out at least one major error and several smaller ones. It was an education to have my work reviewed by such talented individuals, so my thanks to (in alphabetical order) :-
Please note that Feedback link in the bottom right of this page - if you spot any errors or can suggest improvements, please feel free! |