Самопроизвольная перегрузка MySQL

Уважаемые господа,

иногда случается так, что база сама перегружается?
В чем может быть дело?
Вот логи ошибок:

-----------------------------
Number of processes running now: 0
050127 20:53:17 mysqld restarted
050127 20:53:17 InnoDB: Started
/usr/local/mysql/libexec/mysqld: ready for connections.
Version: '4.0.15a-log' socket: '/tmp/mysql.sock' port: 3306
050128 9:18:52 /usr/local/mysql/libexec/mysqld: Normal shutdown

050128 9:18:53 InnoDB: Starting shutdown...
050128 9:18:55 InnoDB: Shutdown completed
050128 9:18:55 /usr/local/mysql/libexec/mysqld: Shutdown Complete

050128 09:18:55 mysqld ended

050128 09:25:14 mysqld started
050128 9:25:15 InnoDB: Started
mysqld got signal 11;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.
We will try our best to scrape up some info that will hopefully help diagnose
the problem, but since we have already crashed, something is definitely wrong
and this may fail.

key_buffer_size=268435456
read_buffer_size=16773120
max_used_connections=0
max_connections=100
threads_connected=0
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_connections = 3538543 K
bytes of memory
Hope that's ok; if not, decrease some variables in the equation.


Number of processes running now: 0
050128 09:25:15 mysqld restarted
050128 9:25:15 InnoDB: Started
/usr/local/mysql/libexec/mysqld: ready for connections.
Version: '4.0.15a-log' socket: '/tmp/mysql.sock' port: 3306
---------------------------

Заранее спасибо!