Description:
if a multithreaded workload crashes mysqld in more than one thread around the same time, the error log contains little or no information, for example:
---------
2016-03-07T04:15:11.694084Z 0 [Note] IPv6 is available.
2016-03-07T04:15:11.696084Z 0 [Note] - '::' resolves to '::';
2016-03-07T04:15:11.697085Z 0 [Note] Server socket created on IP: '::'.
2016-03-07T04:15:11.759593Z 0 [Note] mysqld: ready for connections.
Version: '5.8.0-dmr' socket: '' port: 3306 MySQL Community Server (GPL)
04:19:37 UTC - mysqld got exception 0xc0000005 ;
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.
Attempting to collect some information that could help diagnose the problem.
As this is a crash and something is definitely wrong, the information
collection process might fail.
key_buffer_size=8388608
read_buffer_size=131072
max_used_connections=7
max_threads=151
thread_count=7
connection_count=7
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 67997 K bytes of memory
Hope that's ok; if not, decrease some variables in the equation.
Thread pointer: 0x225d4c00
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...
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if same workload is played in a single thread, we see full stack trace and output in error log.
the above happen in production servers too, for example when some out of memory situation hits all queries, or various other bugs.
How to repeat:
crash mysqld in more than one connection at a time.
Suggested fix:
make it work ;-)