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Re: Restrictions in the OTN downloadable version of 9i?

From: Howard J. Rogers <>
Date: Fri, 5 Jul 2002 09:20:51 +1000
Message-ID: <ag2lau$4oq$>

<> wrote in message news:ag25p8$qul$
> Niall Litchfield <> wrote:
> > 1. that it is possible that some swapping is going on . If you can try
> > reducing the large and java pools (say to 56m each). Swapping the sga
out to
> > disk will kill performance.
> I am pretty sure it isn't. But I'll have to check it of course.
> > 2. That you have sqlnet set to use NT authentication in the sqlnet.ora
> > the client app.
> What do you mean by "the cliant app"? I'm a newbie and don't know what you
> mean by the term sqlnet and what is NT authentication (authentication
> against our NT PDC?).

The client app is the thing you run on your PC which connects over the network to some humungously powerful server running the Oracle database/server itself. An Access front-end, for example. Or a web page which wants data out of the database.

Niall is showing his age, I think!! SQLNET as he used the term refers to the proprietary networking interfaces that Oracle invented to allow connections between a PC and an Oracle database over standard networking protocols such as TCP/IP. Since version 8.0, it's actually been called "Net8". But it's pretty much the same thing. It's Oracle's networking language, if you like.

Then Niall refers to an Oracle-specific configuration file, actually called SQLNET.ORA. It resides on the Client PC, in a directory usually called 'ORACLE_HOME\network\admin'. ORACLE_HOME there is an alias for whatever directory structure you installed the Oracle software into on your PC. It's job is to tell your Client how to attempt to make a connection the the Oracle database -should network traffic be encrypted, for example. And, on NT, should the client authenticate itself with the database using NT security. Dialects of the networking language, if you like.

I think Niall is worried that if you haven't enabled NT authentication, your application will spend a reasonable period of time negotiating other authentication methods, which will make it feel 'stodgy' and slow.

> > The other 'obvious' thing to check is that the tables are analyzed and
> > db is running in CBO mode.
> I'll have to check that (I don't know what is CBO mode :)

Cost Based Optimizer, which has smarts and is much the preferred method of working out how to get at the data in a table. As opposed to RBO, Rule Based Optimizer, which is the old-fashioned way of doing the same thing. The CBO uses statistics on the tables and indexes to work out how best to 'select * from emp'. The RBO uses a set of 15 rules (rule 2 of which is 'if there's an index, use it').

What that means is that if you have a really poor index (lots of empty, wasted space, low selectivity, etc etc) on a table, the RBO will elect to use it to retrieve data, simply because it's there. Rule 2 tells it to. The COst Based Optimizer can see, from its statistics, that the index is hopeless, so it will elect not to use it. If it's a good index, though, then it will. It makes 'intellligent' decisions about how best to get at the data.

So going back to your original post about slow performance, Niall is worried that it's slow because the Optimizer is doing dumb things to get at your data because you haven't enabled the CBO, or because you haven't provided the CBO with sufficient information to do its intelligent stuff by calculating statistics on the tables and indexes.

Regards (and apologies to Niall if I've misinterpreted his queries). HJR
> Thanks for your help!
> Regards,
> Peter
Received on Thu Jul 04 2002 - 18:20:51 CDT

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