This is easy to confirm as described: Version: '5.6.15-debug' socket: '/tmp/mysql.sock' port: 3306 MySQL Community Server (GPL) 11:34:13 UTC - 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. Please help us make Percona Server better by reporting any bugs at http://bugs.percona.com/ key_buffer_size=8388608 read_buffer_size=131072 max_used_connections=1 max_threads=153 thread_count=1 connection_count=1 It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 69196 K bytes of memory Hope that's ok; if not, decrease some variables in the equation. Thread pointer: 0x2b11810 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... stack_bottom = 7fed6c188e38 thread_stack 0x40000 /home/openxs/dbs/p5.6/bin/mysqld(my_print_stacktrace+0x35)[0x96f9b5] /home/openxs/dbs/p5.6/bin/mysqld(handle_fatal_signal+0x43b)[0x66c8fb] /lib64/libpthread.so.0[0x3ffac0eeb0] /home/openxs/dbs/p5.6/bin/mysqld(_Z12setup_tablesP3THDP23Name_resolution_contextP4ListI10TABLE_LISTEPS4_PS7_b+0xaf)[0x6ab0af] /home/openxs/dbs/p5.6/bin/mysqld(_Z29setup_tables_and_check_accessP3THDP23Name_resolution_contextP4ListI10TABLE_LISTEPS4_PS7_bmm+0x37)[0x6ab527] /home/openxs/dbs/p5.6/bin/mysqld(_ZN4JOIN7prepareEP10TABLE_LISTjP4ItemjP8st_orderS5_S3_P13st_select_lexP18st_select_lex_unit+0x6b0)[0x727ac0] /home/openxs/dbs/p5.6/bin/mysqld(_ZN30subselect_single_select_engine7prepareEv+0x699)[0x82aed9] /home/openxs/dbs/p5.6/bin/mysqld(_ZN14Item_subselect10fix_fieldsEP3THDPP4Item+0xad)[0x8299bd] /home/openxs/dbs/p5.6/bin/mysqld(_ZN7set_var5checkEP3THD+0x159)[0x66b939] /home/openxs/dbs/p5.6/bin/mysqld(_Z17sql_set_variablesP3THDP4ListI12set_var_baseE+0x4d)[0x66bf9d] /home/openxs/dbs/p5.6/bin/mysqld(_Z21mysql_execute_commandP3THD+0x374)[0x704ad4] /home/openxs/dbs/p5.6/bin/mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x6c8)[0x70d808] /home/openxs/dbs/p5.6/bin/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x16c1)[0x70ef71] /home/openxs/dbs/p5.6/bin/mysqld(_Z10do_commandP3THD+0x175)[0x710775] /home/openxs/dbs/p5.6/bin/mysqld(_Z24do_handle_one_connectionP3THD+0x1bd)[0x6d125d] /home/openxs/dbs/p5.6/bin/mysqld(handle_one_connection+0x42)[0x6d12e2] /home/openxs/dbs/p5.6/bin/mysqld(pfs_spawn_thread+0x127)[0xa06cf7] /lib64/libpthread.so.0[0x3ffac06ccb] /lib64/libc.so.6(clone+0x6d)[0x3ffa8e0c2d] Trying to get some variables. Some pointers may be invalid and cause the dump to abort. Query (7fed2c006d90): SET STATEMENT myisam_sort_buffer_size=400000, myisam_repair_threads=(select max(v1) from t1), sort_buffer_size=200000, binlog_format=row, keep_files_on_create=OFF, max_join_size=4444440000000 FOR EXECUTE stmt2 Connection ID (thread ID): 1 Status: NOT_KILLED