5.0.24: ---------- [sbester@fc4 sqlthreads]$ ./sqlthreads 30 60 1 0 "drop table if exists t1;create table t1 (i int);lock tables t1 read;show open tables;unlock tables;" 127.0.0.1 3306 test root Testing DB connection before spawning threads.... Connecting.... Connected.... Thread Safe is ON Spawning 30 new threads 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 Database connections are setup! Check above for errors. Query failed (2013) - Lost connection to MySQL server during query: drop table if exists t1;create table t1 (i int);lock tables t1 read;show open tables;unlock tables; 060722 17:27:50 InnoDB: Started; log sequence number 0 98599 060722 17:27:50 [Note] /home/sbester/servers/5.0-bk/bin/mysqld: ready for connections. Version: '5.0.24-debug' socket: '/tmp/my.sock' port: 3306 yes mysqld: sql_base.cc:150: OPEN_TABLE_LIST* list_open_tables(THD*, const char*, const char*): Assertion `share->table_name != 0' failed. mysqld got signal 6; 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=8388572 read_buffer_size=131072 max_used_connections=30 max_connections=100 threads_connected=30 It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size)*max_connections = 225788 K bytes of memory Hope that's ok; if not, decrease some variables in the equation. thd=0x9c2a2b0 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=0xb1694c1c, backtrace may not be correct. Stack range sanity check OK, backtrace follows: 0x80daaa3 handle_segfault + 461 0xa00420 data.7108 + 10486772 0x9c44a6c __stop___libc_freeres_ptrs + 22746732 0x83f75ab __assert_fail + 167 0x81166ae _Z16list_open_tablesP3THDPKcS2_ + 236 0x81c53f7 _Z16fill_open_tablesP3THDP13st_table_listP4Item + 133 0x81c4df9 _Z24get_schema_tables_resultP4JOIN + 389 0x8141798 _ZN4JOIN4execEv + 1844 0x8143d0d _Z12mysql_selectP3THDPPP4ItemP13st_table_listjR4ListIS1_ES2_jP8st_orderSB_S2_SB_mP13select_resultP18st_select_lex_unitP13st_sel + 1543 0x81441fe _Z13handle_selectP3THDP6st_lexP13select_resultm + 444 0x80efa73 _Z21mysql_execute_commandP3THD + 1601 0x80f7770 _Z11mysql_parseP3THDPcj + 330 0x80f8465 _Z16dispatch_command19enum_server_commandP3THDPcj + 3005 0x80f9635 _Z10do_commandP3THD + 537 0x80fa392 handle_one_connection + 3246 0x83c3656 start_thread + 98 0x841b23e __clone + 110 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 0x9c36174 = show open tables;unlock tables thd->thread_id=4 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.