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Oracle Tips by Burleson Consulting
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Load Balancing of Server
Tasks
When CPU overload is experienced, the DBA will generally see periods
during the days when the runqueue gets quite long and other periods
at night when the processors are mostly idle. A common question
asked by a systems administrator is “The CPU is 40-percent idle for
16 hours a day, so why should we add more processors?”
However, there are times when it makes sense to add more processors,
even if the processors are idle during off-peak times. For example,
if you are working in an online environment, the only response time
that matters is the time between 7:00 A.M. and 8:00 P.M. when your
online users are active. The fact that the server is largely idle
during the middle of the night has no bearing on the decision to
upgrade with additional CPUs.
Once we identify the times when the CPU activity is excessive, we
need to go to STATSPACK and examine the activity at the times of the
overload. Once we have identified the times when the processors are
overloaded, we must then see if it is possible to reschedule batch
tasks to run at off-peak hours. On an Oracle database server, tasks
may be scheduled in many ways:
* The dbms_job utility
* The UNIX cron utility
* A TP monitor such as Tuxedo
* Oracle Concurrent Manager (for Oracle Applications)
* SAPGUI if we are running SAP
Regardless of the method of scheduling Oracle tasks, the idea is to
find large batch tasks that may be scheduled during peak processing
times. Our task is to find a large regularly scheduled SQL task that
runs during these times.
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For more details and scripts, see my new book "
Oracle
Tuning: The Definitive Reference", over 900 pages
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instant access to the code depot. |
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