2017-07-27 12:33:02 5bbfbb70 InnoDB: FTS Optimize Removing table bocp_919_swisoimpexs/#sql2-6ceb-37e08f
2017-07-27 12:33:09 6c0c6f70  InnoDB: Assertion failure in thread 1812754288 in file os0thread.cc line 195
InnoDB: Failing assertion: ret == 0
InnoDB: We intentionally generate a memory trap.
InnoDB: Submit a detailed bug report to http://bugs.mysql.com.
InnoDB: If you get repeated assertion failures or crashes, even
InnoDB: immediately after the mysqld startup, there may be
InnoDB: corruption in the InnoDB tablespace. Please refer to
InnoDB: http://dev.mysql.com/doc/refman/5.6/en/forcing-innodb-recovery.html
InnoDB: about forcing recovery.
170727 12:33:09 [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 https://mariadb.com/kb/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: 10.1.25-MariaDB
key_buffer_size=268435456
read_buffer_size=2097152
max_used_connections=172
max_threads=202
thread_count=23
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 1092177 K  bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x625bc008
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 = 0x6c0c669c thread_stack 0x48400
/usr/sbin/mysqld(my_print_stacktrace+0x2d)[0x886530d]
/usr/sbin/mysqld(handle_fatal_signal+0x4e8)[0x83a68d8]
[0xb7718500]
/lib/libc.so.6(abort+0x17a)[0xb71b905a]
/usr/sbin/mysqld[0x859b90c]
/usr/sbin/mysqld[0x85bd103]
/usr/sbin/mysqld[0x85da155]
/usr/sbin/mysqld[0x854671e]
/usr/sbin/mysqld[0x8287394]
/usr/sbin/mysqld(_Z17mysql_alter_tableP3THDPcS1_P14HA_CREATE_INFOP10TABLE_LISTP10Alter_infojP8st_orderb+0x4064)[0x828b6f4]
/usr/sbin/mysqld(_ZN19Sql_cmd_alter_table7executeEP3THD+0x5d3)[0x82dc883]
/usr/sbin/mysqld(_Z21mysql_execute_commandP3THD+0x14ba)[0x81f7e9a]
/usr/sbin/mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x28a)[0x81ffdda]
/usr/sbin/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x23d9)[0x8202f09]
/usr/sbin/mysqld(_Z10do_commandP3THD+0x16e)[0x820345e]
/usr/sbin/mysqld(_Z24do_handle_one_connectionP3THD+0x2e0)[0x82d8af0]
/usr/sbin/mysqld(handle_one_connection+0x3c)[0x82d8bcc]
/lib/libpthread.so.0(+0x6bc9)[0xb76fbbc9]
/lib/libc.so.6(clone+0x5e)[0xb727004e]

Trying to get some variables.
Some pointers may be invalid and cause the dump to abort.
Query (0x37f9018): is an invalid pointer
Connection ID (thread ID): 3661967
Status: NOT_KILLED

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=on,exists_to_in=on,orderby_uses_equalities=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.

We think the query pointer is invalid, but we will try to print it anyway.
Query: ALTER TABLE product_variants_919 DROP INDEX `variant_title` , ADD FULLTEXT `variant_title` (`variant_title`) COMMENT ''

170727 12:33:10 mysqld_safe Number of processes running now: 0
170727 12:33:10 mysqld_safe mysqld restarted