daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: mysqld got signal 11; daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: This could be because you hit a bug. It is also possible that this binary daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: or one of the libraries it was linked against is corrupt, improperly built, daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: or misconfigured. This error can also be caused by malfunctioning hardware. daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: We will try our best to scrape up some info that will hopefully help diagnose daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: the problem, but since we have already crashed, something is definitely wrong daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: and this may fail. daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: key_buffer_size=16777216 daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: read_buffer_size=2093056 daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: max_used_connections=101 daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: max_connections=100 daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: threads_connected=30 daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: It is possible that mysqld could use up to daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: key_buffer_size + (read_buffer_size + sort_buffer_size)*max_connections = 1039983 K daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: bytes of memory daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: Hope that's ok; if not, decrease some variables in the equation. daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: thd=0xa264948 daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: Attempting backtrace. You can use the following information to find out daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: where mysqld died. If you see no messages after this, something went daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: terribly wrong... daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: Cannot determine thread, fp=0x22a85d78, backtrace may not be correct. daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: Stack range sanity check OK, backtrace follows: daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: 0x81ba944 daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: 0xffffe420 daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: 0xa243f9c daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: 0x81d35a8 daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: 0x8227620 daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: 0x82263ea daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: 0x81ce7fd daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: 0x81cd37d daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: 0x81cc812 daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: 0xb7f24b63 daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: 0xb7d9c18a daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: New value of fp=(nil) failed sanity check, terminating stack trace! daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: Please read http://dev.mysql.com/doc/mysql/en/Using_stack_trace.html and follow instructions on how to resolve the stack trace. Resolved daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: stack trace is much more helpful in diagnosing the problem, so please do daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: resolve it daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: Trying to get some variables. daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: Some pointers may be invalid and cause the dump to abort... daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: thd->query at 0xa103190 = DELETE FROM share_network USING share_network, (friends AS f RIGHT JOIN share_network AS s ON f.owner_username=s.username AND f.username=s.shares_with) WHERE share_network.username=s.username AND share_network.shares_with=s.shares_with AND f.owner_username IS NULL daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: thd->thread_id=8167 daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: The manual page at http://www.mysql.com/doc/en/Crashing.html contains daemon.log.0:Nov 2 15:08:42 uk2-host2 mysqld[5278]: information that should help you find out what is causing the crash.