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An expert view on the Oracle (tm) database engine |
JL Computer Consultancy
Health Warning and Disclaimer
Every book I have ever read about Oracle has been out of date, incomplete, ambiguous, misleading or wrong - some much less so than others but the average time taken to finding the first 'error' has never been more than 5 minutes. This turned out to be true even for the book I wrote, by the way, so be warned that my words of wisdom might not be appropriate to your current situation.
Over the years I have found that, despite days of experimentation and testing, when I start writing about some interesting feature of Oracle the first person to review it says something like "it didn't do that for me" and the reason is eventually down to:
· The version of Oracle
· The options installed
· The choice of operating system
· The verson of the operating system
· The hardware
· The hardware configuration
· The choice of filesystem/volume manager
· The volume of data
· The ratios of data distribution
· Some unexpected init.ora parameter
The information on these pages was as accurate as I could make it at the time of writing. However I cannot guarantee that things which worked for me will do the same for you. Nor can I guarantee that the information will remain correct as new versions of Oracle appear.
I have just (April 2004) been browsing through some of the material, and find that a lot of it hasn’t been updated at least five years. Unfortunately I posted a lot of material without date stamps or Oracle version numbers. So make sure you check how relevant something is to your current version. Even if something is still true, it may not be complete, and there may be recent enhancements and developments that you should consider.
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JL Computer Consultancy
What is on this site
Every couple of weeks I hope to put a few more bits and pieces on to this site that may be of use to DBAs, developers, or other Oracle users. These will range from handy little SQL scripts for database monitoring to 'white papers' on how to use various features of the database engine.
You are invited to participate in these web pages by emailing questions, comments, or criticisms. Some of the opinions I tout on these pages are likely to be contentious since I often disagree with the oral traditions (a.k.a. old wives' tales) on how to handle Oracle - if you want to argue a point I'll be delighted to hear from you at jonathan@jlcomp.demon.co.uk.
I don't plan to make these pages very pretty - if you are interested in making Oracle work better you probably don't need pictures to keep you entertained, you're just keen to get the right information. Most of the pages that I put up will be fairly flat texts but from time to time I may upload Word documents or Powerpoint presentations for you to download.
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JL Computer Consultancy
Biographical Information
My name is Jonathan Lewis and I live in the
I have been using database software for more than 23 years, of which the last 20years has been spent using Oracle. For the last seventeen years I have worked as an independent design and trouble-shooting consultant. Much of the work I do is very short-term, often just a couple of days to investigate and comment on a troublesome system.
The systems I have worked on range from a single NT up to 128-node Pyramid RM1000, databases have ranged in size from a tiny (but violent) 50 Mb to 4 Tb with transaction rates from just 60 per day up to 4M per hour, and the locations have varied from 155W (Palo Alto) to 120E (Hong Kong).
I specialise in knowing how the database engine works. If you need to know which features of Oracle may be useful for your specific application I will be able to tell you because I spend a lot of my time investigating how well new features work and how easy it is to break them. If you need to make your system run faster, I can tell you what can be done, and what is most likely to be a cost-effective approach.
I have given several presentations each year to the UK Oracle User Group, both at the annual conference and at meetings of the Unix and DBMS SIGs. I’m also a regular presenter at the Danish Database Forum and I gave two presentations at the IOUG-A conference in 2003, which both were voted into the top 10. Whenever I can fit in with other engagements, I’ve also done various one-day events, or spoken at SIGs around the world.
I write fairly regularly for the
Last, but not least, I am the designer and presenter of the Optimising Oracle (tm) Seminar: an intensive three-day course designed to help you get the most out of the database engine. I have presented this course around the world, both as a public event, and as a private event for large corporations. The same is true for the one-day tutorials targeted at more specific areas of the database.
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Contact Information
Electronic mail address jonathan@jlcomp.demon.co.uk
Web address http://www.jlcomp.demon.co.uk
Office phone +44 (0)7973 188785