Re: Is Oracle slower than sql server

faisal.mansoor_at_gmail.com wrote:
> Hello All
>
> I am having problem with oracle performance in comparsion with SQL
> Server. My application supports both Oracle (9.2) and SQL server (2000)
> database. I have identical schemas installed on both Oracle (installed
> on windows box) and SQL server, all the tables and stored procs are
> identical but I am constantly getting performace problems with oracle.
> Oracle takes twice or more time to perform the same data retrival and
> insertion tasks that SQL server does in half the time. Is it a general
> problem which every one faces? if not then please let me know how can I
> improve performance of on oracle database-- I am not comparing two
> oracle's snapsots, but I want to improve oracle's performance to match
> with SQL server --. Our data base is of medium size and we are running
> both oracle and sql with alomost all default configurations.
>
> Any one having such experience or solution to problem please answer.

I second what everyone else has said, in particular that there is probably particular code and coding practices that are the cause of most of the problems.

9.2 is pretty good about defaults, but there are still some things that my voodoo doll is complaining about.

First of all, you are using Oracle's Cost Based Optimizer (and definitely read about it in the Concepts Guide!) So, if you have an OLTP type system, you may want to blindly change the init.ora parameters optimizer_index_caching to 95 and optimizer_index_cost_adj to 50. This is the _wrong_ way to go about tuning this, but it may give the CBO a nudge in the right direction, telling it to bias more towards index usage. See the admin guide for details.

Second, you can sometimes find gross mistuning with the Oracle OEM product. You can download it if you don't have it, for development purposes only. In particular, there are tuning advisors and some tools for showing if you are seeing the effects of too many full table scans, what plans you are using and so forth. pga_aggregate_target, db_cache_size, shared_pool_size are commonly changed.

Third, you must be sure you are on a recent patch level. Always state the minimum information people need to help you on this group, see http://www.dbaoracle.net/readme-cdos.htm People do want to help, and we've seen the same mistakes over and over viz. SS and Oracle noobs.

Fourth, are you making a proper comparison between SS and Oracle? The big gain comes when you have a bunch of people updating the stuff that a bunch of other people are looking at. If you just have one person using a table, you might as well use Access.

A common mistake is to have undo, redo log or archiving in places where contention takes place, either controller or disk layout bottlenecks. So you might want to use your OS tools to watch that. Also check your alert log to see if it is complaining about anything, see how often your logs are switching.

jg

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