High MySQL CPU time

[bernikm]

Hi

We have noticed a high CPU time (load average over 15 on quad core CPU) during the night. This is caused by MySQL server, as we see from log files.
Can this be because of backing up MySQL data or any other issues ?

There is a screen show from DA reporting high cpu usage ?

Any help will be appriciated.

Regards,Miha

 

[ditto]

I notice that you have a message "open-files-limit=8192" in command value on MySQL on your image above. I think therefor one of your databases has to many tables (more then 8192), that would then cause the backup of that database to not succed. So one thing is that you should check that your database backups all is without errors.. I don't know if this is related to the high cpu.

However, if not all your database backups succed, then you must increase the open-files-limit in etc/my.cnf and then restart mysql. For example you can increase it to 2560 with this line in etc/my.cnf:

open_files_limit=2560

 

[bernikm]

Thanks. All databased backups succeded without any errors.
I have changed open_files_limit=8192 to open_files_limit=2560. We'll see if error repeats.

 

[ditto]

Thanks. All databased backups succeded without any errors.
I have changed open_files_limit=8192 to open_files_limit=2560. We'll see if error repeats.

I made a mistake, sorry! I don't know how I could. But your previous open files limit 8192 is higher then the limit 2560 in my example, so you should change it back again. Again, I am so sorry for my mistake, I read the numbers wrong.

 

[bernikm]

OK. Should I incrise it from 8192 to 16384 ?

 

[ditto]

16384 sounds a little extreme high to me. I think you already has a very high limit. Also it is not for sure that the open files limit is the problem. I can't give advice, sorry.

The only thing I can say for sure, is that if you have a database that contain more tables then your open files limit, is that you would not be able to do database backup of that database. But you say that all your database backups is created without trouble, so therefor I think open files limit is not the problem after all.