Oracle-L: Re:RE: How to tune SQL and CPU usage

From: <dgoulet_at_vicr.com>
Date: Fri, 05 Apr 2002 14:38:20 -0800
Message-ID: <F001.0043D9D7.20020405143820@fatcity.com>

David,

The processes init.ora parameter sets the maximum number of Oracle processes that will run on the server. Beware, if you set that too low then your users will get an error message about max_processes exceeded when they try to logon. Now regrettably we were not given the platform or OS in use so making any kind of recommendation is a little hard. Now in a dedicated server environment a process 'oracle<SID>' equals an end user, so I would ask the question of what are they doing. If you have 20 users all running some really poor statements, then you the machine is going to run slow. What else do you expect! I would also take a look an memory usage. The one I have been really interested in is 'vmstat -s' on HP-UX and take a look for the value of 'rotations of the clock hand'. Anything above 0 is BAD as it means stuff is being swapped out to disk. Get more memory and/or reduce the size of the SGA by cutting back on db_block_buffers, the java_pool, or the shared_pool_size. And get with the users and tune their SQL. Ever since I started with Oracle back in 85 tuning SQL fixes 80% of the problems. Poorly or untuned SQL causes more CPU consumption, more IO, and ultimately more execution time. One other thing, check out the last_analyzed_date in the dba_table data dictionary view where last_analyzed_date is not null. If those tables are being used and they have not been analyzed in a long time either eliminate the statistics with the 'analyze table <table_name> delete statistics;' command or else re-analyze the tables.

Dick Goulet

____________________Reply Separator____________________
Author: com.banilejas_at_codetel.net.do
Date:       4/5/2002 1:30 PM

David,

The parameter PROCESS control the number of process that can be running in the instance.

Yes, you can tune the SQL instruction. You can use the Trace utility or the plan table to do that.

Ramon

-----Original Message-----
M" <david.m.nguyen_at_xo.com>
Sent: Friday, April 05, 2002 4:54 PM
To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com>

Someone uses SQL to query data, he complains it takes too long to get results back from oracle database. He also notices there are many oracle processes running on system that uses much CPU and causing system slow down.

Is there a way to tune SQL to improve query and to set maximum number of running oracle processes?

Thanks,
David
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Author: Nguyen, David M
INET: david.m.nguyen_at_xo.com

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