Bug #43892 Server crash Memcached Functions for MySQL 0.8
Submitted: 26 Mar 2009 17:48 Modified: 27 Apr 2009 7:08
Reporter: Eugene Zolotukhin Email Updates:
Status: No Feedback Impact on me:
Category:MySQL Server: User-defined functions ( UDF ) Severity:S1 (Critical)
Version:5.1.32 OS:Linux ( 2.6.27-gentoo-r7)
Assigned to: CPU Architecture:Any
Tags: Memcached Functions

[26 Mar 2009 17:48] Eugene Zolotukhin
Store value in memcached - crash MySQL server.

Log - mysqld.err :

090326 12:25:19 - 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.

It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 133309 K
bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

thd: 0xa02d400
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 = 0xb2f6c394 thread_stack 0x30000
/opt/libexec/mysqld(my_print_stacktrace+0x28) [0x84a2248]
/opt/libexec/mysqld(handle_segfault+0x39e) [0x81def0e]
/usr/lib/libmemcached.so.2(memcached_generate_hash+0x6a) [0xb3112f7a]
Trying to get some variables.
Some pointers may be invalid and cause the dump to abort...
thd->query at 0xa027470 = select memc_delete('mysql:doc1')
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.

How to repeat:
mysql> select memc_udf_version();
| memc_udf_version() |
| 0.8                |
1 row in set (0.00 sec)

mysql> select memc_servers_set('');
| memc_servers_set('') |
|                              4294967296 |
1 row in set (0.00 sec)

mysql> select memc_server_count();
| memc_server_count() |
|                   1 |
1 row in set (0.00 sec)

mysql> select memc_libmemcached_version();
| memc_libmemcached_version() |
| 0.25                        |
1 row in set (0.00 sec)

mysql> select memc_set('var', 'val');
ERROR 2013 (HY000): Lost connection to MySQL server during query
[27 Mar 2009 7:08] Sveta Smirnova
Thank you fro the report.

I can not repeat described behavior.

Please try with libmemcached-0.26 also.
[27 Apr 2009 23:00] Bugs System
No feedback was provided for this bug for over a month, so it is
being suspended automatically. If you are able to provide the
information that was originally requested, please do so and change
the status of the bug back to "Open".