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Need input on crashes on 3rd mariaDB server


Hi all,

We’re currently using a system with three clustered maria-db masters. We are experiencing occasional (once every three weeks or so) crashes of one of the server, namely our third server, which we use as a dedicated donor for the other two. The crashes point to a BF-BF X lock conflict in the same table. I was wondering how to proceed with identifying and localising the problem and counteracting it. We have already tried to rebuild the database in question from an earlier mysql dump, to no effect. 

Any input is welcome, thanks.


BF-BF X lock conflict
RECORD LOCKS space id 36361 page no 10 n bits 264 index `***REDACTED***` of table `***REDACTED***`.`***REDACTED***` trx id D860A49 lock_mode X locks rec but not gap
140724  6:10:53 [ERROR] 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.

To report this bug, see http://kb.askmonty.org/en/reporting-bugs

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.

Server version: 5.5.38-MariaDB-wsrep-log
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 2329723 K  bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x0x7f57b3412000
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 = 0x7f5c1a16b940 thread_stack 0x48000
(my_addr_resolve failure: fork)
/usr/sbin/mysqld(my_print_stacktrace+0x2b) [0xa95bab]
/usr/sbin/mysqld(handle_fatal_signal+0x398) [0x6ebc58]
/lib64/libpthread.so.0() [0x34e7e0f710]
/lib64/libc.so.6(gsignal+0x35) [0x34e7632925]
/lib64/libc.so.6(abort+0x175) [0x34e7634105]
/usr/sbin/mysqld() [0x50e940]
/usr/sbin/mysqld() [0x92c0ff]
/usr/sbin/mysqld() [0x931799]
/usr/sbin/mysqld() [0x932566]
/usr/sbin/mysqld() [0x968a65]
/usr/sbin/mysqld() [0x85fe3b]
/usr/sbin/mysqld() [0x863ada]
/usr/sbin/mysqld() [0x8642de]
/usr/sbin/mysqld() [0x84e571]
/usr/sbin/mysqld() [0x8337b2]
/usr/sbin/mysqld(handler::ha_delete_row(unsigned char const*)+0xb0) [0x6f3640]
/usr/sbin/mysqld(Delete_rows_log_event::do_exec_row(Relay_log_info const*)+0x10d) [0x7a41dd]
/usr/sbin/mysqld(Rows_log_event::do_apply_event(Relay_log_info const*)+0x26a) [0x798e2a]
/usr/sbin/mysqld(wsrep_apply_cb(void*, void const*, unsigned long, unsigned int, wsrep_trx_meta const*)+0x598) [0x69f988]
/usr/lib64/galera/libgalera_smm.so(galera::TrxHandle::apply(void*, wsrep_cb_status (*)(void*, void const*, unsigned long, unsigned int, wsrep_trx_meta const*), wsrep_trx_meta const&) const+0xb1) [0x7f5c197462c1]
/usr/lib64/galera/libgalera_smm.so(+0x1aaf95) [0x7f5c1977df95]
/usr/lib64/galera/libgalera_smm.so(galera::ReplicatorSMM::apply_trx(void*, galera::TrxHandle*)+0x283) [0x7f5c1977ee03]
/usr/lib64/galera/libgalera_smm.so(galera::ReplicatorSMM::process_trx(void*, galera::TrxHandle*)+0x45) [0x7f5c1977f6f5]
/usr/lib64/galera/libgalera_smm.so(galera::GcsActionSource::dispatch(void*, gcs_action const&, bool&)+0x2c9) [0x7f5c1975c349]
/usr/lib64/galera/libgalera_smm.so(galera::GcsActionSource::process(void*, bool&)+0x63) [0x7f5c1975c823]
/usr/lib64/galera/libgalera_smm.so(galera::ReplicatorSMM::async_recv(void*)+0x93) [0x7f5c1977b3f3]
/usr/lib64/galera/libgalera_smm.so(galera_recv+0x23) [0x7f5c19790743]
/usr/sbin/mysqld() [0x6a037f]
/usr/sbin/mysqld(start_wsrep_THD+0x365) [0x527415]
/lib64/libpthread.so.0() [0x34e7e079d1]
/lib64/libc.so.6(clone+0x6d) [0x34e76e8b5d]

Trying to get some variables.
Some pointers may be invalid and cause the dump to abort.
Query (0x0): is an invalid pointer
Connection ID (thread ID): 17

Optimizer switch: index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off,table_elimination=on,extended_keys=off

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.
140724 06:10:53 mysqld_safe Number of processes running now: 0
140724 06:10:53 mysqld_safe WSREP: not restarting wsrep node automatically
140724 06:10:53 mysqld_safe mysqld from pid file /var/lib/mysql/***hostnameredacted***.pid ended