Comment 25 for bug 1729536

I am seeing this as well in percona-xtradb-cluster-server-5.7 (5.7.21-29.26-1.xenial) / mysqld Ver 5.7.21-20-57 for debian-linux-gnu on x86_64 (Percona XtraDB Cluster (GPL), Release rel20, Revision 1702aea, WSREP version 29.26, wsrep_29.26)

This appears related to: https://jira.percona.com/browse/PS-745 which is marked as closed

When executing large SQL scripts, often those with an ALTER TABLE (but not always) I experience t least one of the nodes in the cluster failing with the same stack trace:

2018-04-10 09:02:33 0x7f6701ffb700 InnoDB: Assertion failure in thread 140080391894784 in file pars0pars.cc line 822
InnoDB: Failing assertion: sym_node->table != NULL
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/5.7/en/forcing-innodb-recovery.html
InnoDB: about forcing recovery.
16:02:33 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.
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.
Please help us make Percona XtraDB Cluster better by reporting any
bugs at https://jira.percona.com/projects/PXC/issues

key_buffer_size=16777216
read_buffer_size=131072
max_used_connections=37
max_threads=151
thread_count=9
connection_count=0
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 76198 K bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x0
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 = 0 thread_stack 0x30000
/usr/sbin/mysqld(my_print_stacktrace+0x3b)[0xeba1fb]
/usr/sbin/mysqld(handle_fatal_signal+0x499)[0x77f3d9]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x11390)[0x7f67d05b1390]
/lib/x86_64-linux-gnu/libc.so.6(gsignal+0x38)[0x7f67cf96a428]
/lib/x86_64-linux-gnu/libc.so.6(abort+0x16a)[0x7f67cf96c02a]
/usr/sbin/mysqld[0x74e57c]
/usr/sbin/mysqld(_Z21pars_insert_statementP10sym_node_tPvP10sel_node_t+0x3a8)[0xfaf188]
/usr/sbin/mysqld(_Z7yyparsev+0x1227)[0x11ddd17]
/usr/sbin/mysqld(_Z8pars_sqlP11pars_info_tPKc+0x9e)[0xfb09de]
/usr/sbin/mysqld(_Z13fts_parse_sqlP11fts_table_tP11pars_info_tPKc+0x198)[0x11bd978]
/usr/sbin/mysqld(_Z14fts_write_nodeP5trx_tPP10que_fork_tP11fts_table_tP12fts_string_tP10fts_node_t+0x292)[0x1198262]
/usr/sbin/mysqld[0x119b95b]
/usr/sbin/mysqld(_Z14fts_sync_tableP12dict_table_tbbb+0x351)[0x11a0d31]
/usr/sbin/mysqld(_Z23fts_optimize_sync_tablem+0x45)[0x11a8eb5]
/usr/sbin/mysqld(_Z19fts_optimize_threadPv+0x57c)[0x11b248c]
/lib/x86_64-linux-gnu/libpthread.so.0(+0x76ba)[0x7f67d05a76ba]
/lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f67cfa3c41d]
You may download the Percona XtraDB Cluster operations manual by visiting
http://www.percona.com/software/percona-xtradb-cluster/. You may find information
in the manual which will help you identify the cause of the crash.

----

The crash happens within the Full Text optimization thread, specifically in pars_insert_statement, when it's trying to open a table. I surmise that dict_load_table_one is returning NULL when a FTS table can't be opened, and the "Failing assertion: sym_node->table != NULL" means the table to insert into could not be opened