OK, I reproduced the same on Percona Server 5.6.33. The test case: On a sandbox instance, used these settings: innodb_flush_log_at_trx_commit = 0 innodb_flush_method = O_DIRECT innodb_buffer_pool_size = 1G innodb_log_file_size = 1G max_allowed_packet = 128M innodb_ft_result_cache_limit = 16M -- Created table: mysql [localhost] {msandbox} (test) > CREATE TABLE `text_content` ( `text_content_id` int(11) NOT NULL AUTO_INCREMENT, `content_id` int(11) NOT NULL DEFAULT '0', `active` enum('Y','N') DEFAULT 'Y', `revision` smallint(6) NOT NULL DEFAULT '1', `page` smallint(6) NOT NULL DEFAULT '1', `text_content` mediumtext, `created_date` datetime NOT NULL DEFAULT '0000-00-00 00:00:00', PRIMARY KEY (`text_content_id`), KEY `key_content_active` (`content_id`,`active`), FULLTEXT KEY `text_content` (`text_content`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8; Query OK, 0 rows affected (0.13 sec) -- installed procedure from http://kedar.nitty-witty.com/blog/generate-random-test-data-for-mysql-using-routines: mysql [localhost] {msandbox} (test) > source ../populate_dummy_data.sql ... Query OK, 0 rows affected (0.00 sec) -- populated 500k rows: mysql [localhost] {msandbox} (test) > call populate('test','text_content',500000,'N'); +---------------------+ | Developed by | +---------------------+ | Kedar Vaijanapurkar | +---------------------+ 1 row in set (2 min 5.20 sec) -- updated most of the rows, the blob column with text file from mysqlsandbox installation: mysql [localhost] {msandbox} (test) > update text_content set text_content=LOAD_FILE('/home/przemyslaw.malkowski/sandboxes/ps5.6.33/clear') where text_content_id>40000; Query OK, 460500 rows affected (5 min 47.44 sec) Rows matched: 460500 Changed: 460500 Warnings: 0 -- executed query: mysql [localhost] {msandbox} (test) > select content_id,page from text_content where MATCH (text_content.text_content) AGAINST ('+databases +language +compliance +limitations ' IN BOOLEAN MODE) limit 300; ERROR 2013 (HY000): Lost connection to MySQL server during query -- crash trace: Version: '5.6.33-79.0' socket: '/tmp/mysql_sandbox25633.sock' port: 25633 Percona Server (GPL), Release 79.0, Revision 2084bdb 2016-10-21 11:05:29 7f8460c42700 InnoDB: Assertion failure in thread 140206535878400 in file fts0que.cc line 3659 InnoDB: Failing assertion: !query->intersection 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. 15:05:29 UTC - 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. 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. Please help us make Percona Server better by reporting any bugs at http://bugs.percona.com/ key_buffer_size=8388608 read_buffer_size=131072 max_used_connections=1 max_threads=153 thread_count=1 connection_count=1 It is possible that mysqld could use up to key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 69055 K bytes of memory Hope that's ok; if not, decrease some variables in the equation. Thread pointer: 0x7f83fbf33000 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 = 7f8460c41e00 thread_stack 0x40000 /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld(my_print_stacktrace+0x2e)[0x8e746e] /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld(handle_fatal_signal+0x491)[0x6aa011] /lib/x86_64-linux-gnu/libpthread.so.0(+0x10330)[0x7f8460693330] /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x37)[0x7f845e82ec37] /lib/x86_64-linux-gnu/libc.so.6(abort+0x148)[0x7f845e832028] /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld[0xab4a02] /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld[0x91112e] /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld(_ZN15Item_func_match11init_searchEb+0x163)[0x65c4b3] /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld(_Z12init_ftfuncsP3THDP13st_select_lexb+0x58)[0x6e1018] /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld(_ZN4JOIN8optimizeEv+0x24c2)[0x85e992] /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld(_Z12mysql_selectP3THDP10TABLE_LISTjR4ListI4ItemEPS4_P10SQL_I_ListI8st_orderESB_S7_yP13select_resultP18st_select_lex_unitP13st_select_lex+0x21e)[0x73f1ce] /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld(_Z13handle_selectP3THDP13select_resultm+0x195)[0x73f4e5] /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld[0x5d0977] /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld(_Z21mysql_execute_commandP3THD+0x1d68)[0x71e2e8] /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x598)[0x721978] /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0xee8)[0x7228f8] /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld(_Z24do_handle_one_connectionP3THD+0x15f)[0x6f612f] /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld(handle_one_connection+0x47)[0x6f6217] /home/przemyslaw.malkowski/sandboxes/tarballs/percona5.6.33/bin/mysqld(pfs_spawn_thread+0x143)[0xb3f6a3] /lib/x86_64-linux-gnu/libpthread.so.0(+0x8184)[0x7f846068b184] /lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f845e8f237d] Trying to get some variables. Some pointers may be invalid and cause the dump to abort. Query (7f83f5c1e010): select content_id,page from text_content where MATCH (text_content.text_content) AGAINST ('+databases +language +compliance +limitations ' IN BOOLEAN MODE) limit 300 Connection ID (thread ID): 4 Status: NOT_KILLED You may download the Percona Server operations manual by visiting http://www.percona.com/software/percona-server/. You may find information in the manual which will help you identify the cause of the crash. 161021 11:05:30 mysqld_safe Number of processes running now: 0