High Cpu Usage after MySQL Update (5.1 to 5.5) on CentOS 5.8 (64 Bit)

General Problem: Server load 20.92 (8 CPUs) [it varies from 7 to 40, normally it should be less than 1)

Server Specs:
Dedicated Server
Intel Core i7 (8 Cpus)
RAM: 8GB
We use WHM and we have about 25 databases (8 are wordpress) most of which are MyISAM.
We are using the default MySQL options as always.

Now WHM won’t allow us to downgrade to mysql 5.1
When we disable mysql, cpu goes down to 0.20 (8 CPUs)

As i said, the problem is CPU gets over 100%.

Now when i look at PhpMyAdmin Statistics:
“Query statistics: Since its startup, 387,979 queries have been sent to the server”
And the server was running for 20 minutes.

show status like ‘%onn%’; prints this:

| Aborted_connects         | 1     |
| Connections              | 93576 | (and growing by ~100 per second)
| Max_used_connections     | 46    |
| Threads_connected        | 7     |

7 rows in set (0.00 sec)
When i shut down apache2 no new connections are made.

/etc/my.cnf

[mysqld]
log-slow-queries
default-storage-engine=MyISAM
max_connections=500
innodb_file_per_table=1
thread_concurrency=16
wait_timeout=120

Answer

Try this command: sudo date `date +”%m%d%H%M%C%y.%S”

See the following blog post about that problem.

http://blog.mozilla.org/it/2012/06/30/mysql-and-the-leap-second-high-cpu-and-the-fix/

Attribution
Source : Link , Question Author : Byivan , Answer Author : Michael Maier

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