CPU Load post Lunch break !!!

Hello All,

In continuation with all my previous threads with regards to CPU load. I have a one very interesting find.

The LOAD of the server remains fine all the while from Morning till Lunch Time, But IT IS ONLY AFTER LUNCH that the load SPIKES UP !! and this is the matter of concern to me any my client.

Can any one let me know if there is any variable that needs to refresh it self after ideal time out on the server, Or is there any variable that builds up some kind of cache during the break and that in turn causes heavy CPU load ?..any thing that can be the cause of load post lunch and not before it. B’coz the nature of the work does not change and the number of employees working on the server remain constant, But just after the break it is that causes the issue.

I believe it is something in the interim that accumulates itself in the CPU and causes the load to rise.

Any one reading this, Please suggest some tweak that i can adjust ??

Please any one ?

Thank you once again.

Does all the employees get back from lunch at the same time and hit the “refresh” button at the about the same time?
Does any one of the employees run any reports after lunch?
Are any backups (or analyze table) wrongly configured to start at 12 am instead of 12 pm?

Because database doesn’t normally start consuming CPU by itself. In 99% of the cases there is an overlooked external input that sparks it.
The only thing that I know of that actually can cause the CPU to spike even under certain odd situations of light load on MySQL is the InnoDB spin locks:
Ref: http://dev.mysql.com/doc/refman/5.5/en/innodb-performance-sp in_lock_polling.html

And this is also good to read:
http://www.mysqlperformanceblog.com/2006/07/17/show-innodb-s tatus-walk-through/
http://www.mysqlperformanceblog.com/2011/09/02/understand-in nodb-spin-waits-win-a-percona-live-ticket/


Thank you for standing by on my issue

To answer to the first part of your question, No, not all employees go or return from lunch at the same time !

There are No backups and NO cron jobs scheduled during office hours.

Thank you for the links, you have provided !!!