061206 11:07:23 InnoDB: Started; log sequence number 0 43932 061206 11:07:23 [Note] mysqld: ready for connections. Version: '5.0.30-Debian_0.dotdeb.1-log' socket: '/var/run/mysqld/mysqld.sock' port: 3306 Dotdeb Sarge backport 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=16777216 read_buffer_size=131072 max_used_connections=1 max_connections=100 threads_connected=1 It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size)*max_connections = 233983 K bytes of memory Hope that's ok; if not, decrease some variables in the equation. thd=0x8abf918 Attempting backtrace. You can use the following information to find out where mysqld died. If you see no messages after this, something went terribly wrong... Cannot determine thread, fp=0xbe5fde08, backtrace may not be correct. Stack range sanity check OK, backtrace follows: 0x81be4c4 0x4005a825 0x41ffe332 0x41ffd7ef 0x8160b6e 0x81463e1 0x814dbd0 0x821e7a7 0x8219f11 0x8218498 0x8218347 0x8218498 0x8218347 0x8218498 0x8218347 0x8218498 0x8218347 0x8218498 0x82182ad 0x8217ef5 0x8208050 0x820931a 0x82053e0 0x81d2eda 0x81dad9e 0x81d15c7 0x81d10ed 0x81d0512 0x40054e51 0x4029f8aa New value of fp=(nil) failed sanity check, terminating stack trace! Please read http://dev.mysql.com/doc/mysql/en/using-stack-trace.html and follow instructions on how to resolve the stack trace. Resolved stack trace is much more helpful in diagnosing the problem, so please do resolve it Trying to get some variables. Some pointers may be invalid and cause the dump to abort... thd->query at 0x8af7e58 = SELECT *, STEUERN_CH_E(steuern_kanton.kantonID,0,0,0) AS kant_e, STEUERN_CH_E(steuern_kanton.kantonID,0,0,0,1) AS gem_e, STEUERN_CH_V(steuern_kanton.kantonID,0,0,0) AS kant_v, STEUERN_CH_V(steuern_kanton.kantonID,0,0,0,1) AS gem_v FROM steuern_kanton CROSS JOIN bezirk USING (kantonID) CROSS JOIN gemeinde USING (bezirkID) CROSS JOIN plz4 USING (gemeindeID) CROSS JOIN steuern USING (gemeindeID) WHERE 1 AND ( plz4.plzname LIKE '%as%' OR plz4.plzname LIKE '%as% ') GROUP BY gemeinde.gemeindeID thd->thread_id=1 The manual page at http://www.mysql.com/doc/en/Crashing.html contains information that should help you find out what is causing the crash.