Comment 1 for bug 1649500

I'm able to reproduce with mentioned steps.

mysql> set global audit_log_rotate_on_size=524288000;SET GLOBAL audit_log_flush = ON;
Query OK, 0 rows affected (0.04 sec)

Query OK, 0 rows affected (0.00 sec)

mysql> show variables like '%audit%';
+-----------------------------+---------------+
| Variable_name | Value |
+-----------------------------+---------------+
| audit_log_buffer_size | 1048576 |
| audit_log_exclude_accounts | |
| audit_log_exclude_commands | |
| audit_log_exclude_databases | |
| audit_log_file | audit.log |
| audit_log_flush | OFF |
| audit_log_format | OLD |
| audit_log_handler | FILE |
| audit_log_include_accounts | |
| audit_log_include_commands | |
| audit_log_include_databases | |
| audit_log_policy | ALL |
| audit_log_rotate_on_size | 524288000 |
| audit_log_rotations | 0 |
| audit_log_strategy | ASYNCHRONOUS |
| audit_log_syslog_facility | LOG_USER |
| audit_log_syslog_ident | percona-audit |
| audit_log_syslog_priority | LOG_INFO |
+-----------------------------+---------------+
18 rows in set (0.00 sec)

$ for i in `seq 10000`; do mysql -e 'select * from mysql.user limit 1'; done

And it just hanged and I can't connect to MySQL server.

However, audit_log_flush shows OFF which is turned ON dynamically. This doesn't seems dynamic variable but doc mentions it's dynamic https://www.percona.com/doc/percona-server/5.6/management/audit_log_plugin.html#audit_log_flush

Interestingly, when I enabled audit_log_flush & audit_log_rotate_on_size from my.cnf after restarting instance I couldn't reproduce same problem.

$ for i in `seq 10000`; do mysql -e 'select * from mysql.user limit 1'; done

This completed absolutely fine. It could be related to audit_log_flush handling.