на 3 mysql-серверах : все 5.1.32 -  два из них на линуксах Gentoo(2.6.28 x86_64 ) и OpenSuse (2.6.18.2-34-default) - на них mysql собран вручную .. и один FreeBSd-7 - тут Mysql собран из портов (7.1-PRERELEASE #14 ) ..
на одном и том же селекте
SELECT *   FROM probid_fields_data   WHERE  boxid='91' and auctionid='1936673' ;
все сервера видають ошибку
ERROR 2013 (HY000): Lost connection to MySQL server during query
и в логах:

090322 20:00:21 - 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=2147483648
read_buffer_size=4194304
max_used_connections=155
max_threads=300
threads_connected=11
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 5786596 K
bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

thd: 0x7f770005e110
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 = 0x7f772b4d2f70 thread_stack 0x40000
[0x691e24]
[0x4ba590]
[0x629730]
[0x649052]
[0x6745ae]
[0x5a170a]
[0x589b67]
[0x584082]
[0x58416b]
[0x513dc0]
[0x51ea65]
[0x51eebd]
[0x531a62]
[0x52dc24]
[0x53333c]
[0x4c763a]
[0x4cdab0]
[0x4cf996]
[0x4d07f3]
[0x4d10a6]
[0x4c3e4e]
[0x625ed7]
[0x715879]
Trying to get some variables.
Some pointers may be invalid and cause the dump to abort...
thd->query at 0x7f77244f1600 is an invalid pointer
thd->thread_id=113784
thd->killed=NOT_KILLED
The manual page at http://dev.mysql.com/doc/mysql/en/crashing.html contains
information that should help you find out what is causing the crash.

resolve_stack_dump -s /tmp/mysqld.sym -n  /tmp/mysql.stack
0x691e24 my_print_stacktrace + 36
0x4ba590 handle_segfault + 848
0x629730 __restore_rt + 0
0x649052 mi_lock_database + 34
0x6745ae myrg_lock_database + 110
0x5a170a _ZN7handler16ha_external_lockEP3THDi + 26
0x589b67 _ZN18QUICK_RANGE_SELECT20init_ror_merged_scanEb + 167
0x584082 _ZN26QUICK_ROR_INTERSECT_SELECT20init_ror_merged_scanEb + 114
0x58416b _ZN26QUICK_ROR_INTERSECT_SELECT5resetEv + 75
0x513dc0 _ZL21join_init_read_recordP13st_join_table + 32
0x51ea65 _Z10sub_selectP4JOINP13st_join_tableb + 101
0x51eebd _ZL9do_selectP4JOINP4ListI4ItemEP8st_tableP9Procedure + 637
0x531a62 _ZN4JOIN4execEv + 2354
0x52dc24 _Z12mysql_selectP3THDPPP4ItemP10TABLE_LISTjR4ListIS1_ES2_jP8st_orderSB_S2_SB_yP13select_resultP18st_select_lex_unitP13st_select + 292
0x53333c _Z13handle_selectP3THDP6st_lexP13select_resultm + 364
0x4c763a _ZL21execute_sqlcom_selectP3THDP10TABLE_LIST + 154
0x4cdab0 _Z21mysql_execute_commandP3THD + 14448
0x4cf996 _Z11mysql_parseP3THDPKcjPS2_ + 854
0x4d07f3 _Z16dispatch_command19enum_server_commandP3THDPcj + 3667
0x4d10a6 _Z10do_commandP3THD + 230
0x4c3e4e handle_one_connection + 558
0x625ed7 start_thread + 199
0x715879 clone + 121

desc probid_fields_data
    -> ;
+-----------+------------+------+-----+---------+----------------+
| Field     | Type       | Null | Key | Default | Extra          |
+-----------+------------+------+-----+---------+----------------+
| id        | int(11)    | NO   | MUL | NULL    | auto_increment |
| auctionid | int(11)    | NO   | MUL | 0       |                |
| ownerid   | int(11)    | NO   |     | 0       |                |
| boxid     | int(11)    | NO   | MUL | 0       |                |
| boxvalue  | text       | NO   |     | NULL    |                |
| active    | tinyint(4) | NO   |     | 1       |                |
+-----------+------------+------+-----+---------+----------------+
6 rows in set (0.00 sec)

# free
             total       used       free     shared    buffers     cached
Mem:      16463976   10003524    6460452          0      82044    9153468
-/+ buffers/cache:     768012   15695964
Swap:      2104504      14640    2089864

my.cnf тут  http://vol-kovtun.narod.ru/unix/gentoo.html
другие my.cnf немного отличаютса ..

роскажите в чем может бить причина ?