Hi!

i used the top command on the server to see which process consuming the cpu . and i found that, some times mysql cpu usage become 50% for a secound and then drop to the normal ...

1st of all, is it normal ? should i take any steps to investigate the issue ?

thanks.

You have to check the mysql processes, try this,

pidof mysqld

and you can download and install a handy tool called "mytop"
to monitor which user have too many connection in mysql. Also try tweaking the /etc/my.cnf.

That's pretty normal if a big query is being run. If you want to look into it further get a copy of mytop and install it (it's the top command but for MySQL). It'll let you see what's doing it.