Saturday, 6 March 2010

multible blocksizes in an Oracle Database

In short: Not useful.

More elaborated: Messy, waste of memory-space and admin-effort.

Let me explain:

I've come across this discussion again and I considered myself lucky that Charles Hooper has done all the research already.

I'm summarizing his findings here:

Multiple Blocksizes do NOT offer Any Proven Advantage.

The theory about more efficient indexes and better managed cache is good, and I dont deny there is good reasoning behind it. But in practice, having multiple blocksizes and multiple db-nK-caches doesnt make a difference.

It is a waste of the extra (little bit of) work.

And most likely, you end up wasteing cache-space because you hard-divide the cache space into chunks and you prevent the Oracle LRU-mechanism from utilizing all available cache as it sees fit.

Of course, you may be the exception that proves the rule, and I would like to hear from you in that case, but until further notice, I'll stick with my motto:

Simple = Better.

Saturday, 6 February 2010

sqldeveloper - the swiss knife for Oracle.

SQL Developer is the Swiss Army Knife for Oracle Developers (and DBAs and other interested parties, for that matter)This post is about SQLDeveloper and about "The Book" that introduces it.

In short: Recommended. The book and the tool.

Recommended for Newbies and experienced folk alike.

Recommended for Developers, DBA's and other users of the database.

Let me explain why.

Manuals are sooo last century.
Remember the boxes that came with Oracle7 and Oracle8/i?
(looks for picture of pallet)

Then in Oracle 9, there was a CD with .pdfs. I've seen people consume a tree or two on that, and I'm guilty myself of selectively printing chapters to study on long-distance trains and put yellow-stickies on. Laptop batteries were brief in those days.

I would be interested to know how many ppl dont carry books at all anymore, just .pdfs on laptops, e-readers or ipads [jokelink]. I have switched to laptop-reading for most manuals, but not for leasure-books. And the person who used to say: "From their bookshelf, I recognize the type of DBA/Developer" will have to flip through his customer's laptop or ipad to do an assesment"

Normally, I hestitate to recommend books to developers (or anyone) because there is a lot of rambling rubbish out there. Books tend to follow the hobby-horse of the author (at best), books may contains outdated information (a lot, given the pace of Oracle 7-8-9-10-11, the opt_cost_adj=120 and the go_faster=true|false come to mind). At worst, the information in books can be rampantly wrong. Notably Jonathan Lewis points out that you should be critical of information on the internet, the same caveat applies to the bookshop: Dont believe everything that is printed.

Oracle SQL Developer by Sue Harper, another link to the publisher ...But the SQLDeveloper book by Sue Harper is one of the Good Exceptions.

This is how a good introductory book should be.
It simply presents the tool and all its possibilities.
It doesnt impose a methodology.
It doesnt try to convince you of anything.

Like any truly good book, it allows you to do your own thinking.

And it does a very good job of introducing the tool and its many possible uses.
Check it out, and decide for yourself. You might be surprised.

To get an impression: you can read the first chapter Here at the publishers website.

To the Newbie developer it is a good introduction, to the more seasoned SQL-Plus user (or users of other tools, for that matter) it is a good reference.

As a die-hard command-liner, I will of course stick to my #$% prompts, but for those of you who have to be more productive, or who are forced off other tools for cost-cutting reasons this book can help you on your road to fortune and glory.

I'd also like to mention that there is a trend: Sue is not the first oracle Product Manager to write a book, and I had already enjoyed the writing of Larry Carpenter who runs the team that nurtured DataGuard into bloom. I can heartily recommend his book as well. I have recently used that too, to convince Customers/managers/leaders/victims/architects of the benefits of Dataguard (and soon to come: GoldenGate, running on a system near you). Larrys book was reviewd by Harold "Prutser" van Brederode

A tip of the hat and a big "Thank You" to both authors for going through the process of writing those books!