Re: Okay where do I start?

Daniel A. Morgan <Daniel.Morgan_at_attws.com> wrote in message news:3B2FD0B0.D5549E6E_at_attws.com...
> Paul Schmidt wrote:
> > One of my clients decided he wants to use Oracle, since I am not an
> > Oracle expert, I have some questions.
>
> Yes. But as you are not an "Oracle expert" I seriously question whether
> you will be able to deliver something without getting a mentor.

This is very good advice. Don't just think you can use Oracle as a datastore and create some tables and start filling them with information and Oracle will handle it all fast and efficiently. I made that mistake when converting an application to Oracle. I figured Oracle was a good, fast database and was overkill for my needs, so it would just handle whatever I threw at it easily. Sure enough, it did - for about 3 months, and then there were lots of users very unhappy with the performance of their system. Oracle will run like a dog if it isn't tuned properly, and you need to know a lot about Oracle before you can tune it properly.

You will need to attack performance issues from three angles - database settings/structure, schema design, and the way your application queries Oracle. All are critical, and more of one will not make up for a lack of another. There are no easy answers to give here either - you need to know in detail about all the issues that will affect performance in each of these areas and what you can do to optimize response time.

Do not install a standard database as it comes from CD. While this seems like an easy way to start, the standard installation is unsatisfactory in so many ways - disk block size for example. Perhaps you can use a standard installation for practice but do not put one into production. You will need to customize your database parameters to give you better performance and you need to know how to do this before you install the database.

For example, not knowing any better at the time, I had a standard installation in a production environment. It had a data block buffer cache hit ratio of 43.09%. This is only one of many system metrics you will need to know about, but is one of the more vital ones. 43.09% is extremely bad - it shouldn't get below 89%. I have since studied Oracle tuning and optimized it from all angles, and have got 98.83% now. Needless to say, the client is much happier, but this whole issue could have been avoided by some prior knowledge. This will happen to you unless you come up to speed on Oracle before you start your application design. A bit of study now will save you and your client much anguish later.

If you can't get or afford a mentor, at least read some Oracle books before you start. I recommend Oracle8: The Complete Reference by George Koch and Kevin Loney. This is the Oracle bible. Also, you will need to know the concepts behind database administration and tuning, so get Oracle8 Advanced Tuning and Administration by Aronoff, Loney and Sonawalla, and probably also Oracle8 DBA Handbook by Kevin Loney - there is some overlap in these books, but they have concepts you need to know so you can detect what needs to be changed so that your database performs better. I didn't have a mentor, and these books got me through. Obviously, get the right edition for your Oracle version.

There is no quick answer, but a week or so spent researching Oracle now is a wise investment.

Christopher Latta Received on Tue Jun 19 2001 - 23:40:19 CDT