(gdb) c
Continuing.
[New Thread 0x7f1fac0ad700 (LWP 15679)]

Thread 13 "mariadbd" received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x7f1fac0ad700 (LWP 15679)]
optimize_keyuse (join=join@entry=0x7f1f6c067370, 
    keyuse_array=keyuse_array@entry=0x7f1f6c0676c8)
    at /home/mariadb/sql/sql_select.cc:7687
7687              keyuse->ref_table_rows= MY_MAX(tmp_table->file->stats.records, 100);
(gdb) bt
#0  optimize_keyuse (join=join@entry=0x7f1f6c067370, 
    keyuse_array=keyuse_array@entry=0x7f1f6c0676c8)
    at /home/mariadb/sql/sql_select.cc:7687
#1  0x000055ec5875b233 in JOIN::add_keyuses_for_splitting (
    this=0x7f1f6c067370) at /home/mariadb/sql/opt_split.cc:847
#2  0x000055ec582aa7dc in make_join_statistics (
    keyuse_array=0x7f1f6c0666d0, tables_list=..., 
    join=0x7f1f6c066378) at /home/mariadb/sql/sql_select.cc:6020
#3  JOIN::optimize_inner (this=0x7f1f6c066378)
    at /home/mariadb/sql/sql_select.cc:2626
#4  0x000055ec582ae1fa in JOIN::optimize (
    this=this@entry=0x7f1f6c066378)
    at /home/mariadb/sql/sql_select.cc:1944
#5  0x000055ec5806d1bc in st_select_lex::optimize_unflattened_subqueries (this=0x7f1f6c014120, const_only=const_only@entry=false)
    at /home/mariadb/sql/sql_lex.cc:4889
#6  0x000055ec58038c79 in mysql_insert (thd=thd@entry=
    0x7f1f6c000c58, table_list=<optimized out>, fields=..., 
    values_list=..., update_fields=..., update_values=..., 
    duplic=<optimized out>, ignore=<optimized out>, 
    result=<optimized out>) at /home/mariadb/sql/sql_lex.h:985
--Type <RET> for more, q to quit, c to continue without paging--
#7  0x000055ec580f962a in mysql_execute_command (
    thd=0x7f1f6c000c58, 
    is_called_from_prepared_stmt=<optimized out>)
    at /home/mariadb/sql/sql_parse.cc:4429
#8  0x000055ec580c6cce in mysql_parse (thd=0x7f1f6c000c58, 
    rawbuf=<optimized out>, length=<optimized out>, 
    parser_state=<optimized out>)
    at /home/mariadb/sql/sql_parse.cc:7748
#9  0x000055ec580e8755 in dispatch_command (command=COM_QUERY, 
    thd=0x7f1f6c000c58, packet=<optimized out>, 
    packet_length=<optimized out>, blocking=<optimized out>)
    at /home/mariadb/sql/sql_class.h:1551
#10 0x000055ec580f01ad in do_command (thd=0x7f1f6c000c58, 
    blocking=blocking@entry=true)
    at /home/mariadb/sql/sql_parse.cc:1406
#11 0x000055ec584f0732 in do_handle_one_connection (
    connect=<optimized out>, put_in_cache=true)
    at /home/mariadb/sql/sql_connect.cc:1418
#12 0x000055ec584f143d in handle_one_connection (
    arg=arg@entry=0x55ec5c138ef8)
    at /home/mariadb/sql/sql_connect.cc:1320
--Type <RET> for more, q to quit, c to continue without paging--
#13 0x000055ec590b5c88 in pfs_spawn_thread (arg=0x55ec5c0de048)
    at /home/mariadb/storage/perfschema/pfs.cc:2201
#14 0x00007f1fc20b0609 in start_thread (arg=<optimized out>)
    at pthread_create.c:477
#15 0x00007f1fc1c81353 in clone ()
    at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95