Troubleshooting the InnoDB memcached Plugin The  innodb_memcached_config.sql  configuration script also creates an entry for the  demo_test table in the  innodb_memcache.containers  table. mysql>  SELECT * FROM innodb_memcache.containers\G *************************** 1. row *************************** name: aaa db_schema: test db_table: demo_test key_columns: c1 value_columns: c2 flags: c3 cas_column: c4 expire_time_column: c5 unique_idx_name_on_key: PRIMARY mysql>  SELECT * FROM test.demo_test; +----+------------------+------+------+------+ | c1 | c2 | c3 | c4 | c5 | +----+------------------+------+------+------+ | AA | HELLO, HELLO | 8 | 0 | 0 | +----+------------------+------+------+------+ 15.20.9 Troubleshooting the InnoDB memcached Plugin failed to set rlimit for open files. Try running as root or requesting smaller maxconns value. The error message is from the  memcached  daemon. One solution is to raise the OS limit for the number of open files. The commands for checking and increasing the open file limit varies by operating system. This example shows commands for Linux and macOS: The other solution is to reduce the number of concurrent connections permitted for the  memcached daemon. To do so, encode the  -c memcached  option in the  daemon_memcached_option configuration parameter in the MySQL configuration file. The  -c  option has a default value of 1024. •To troubleshoot problems where the  memcached  daemon is unable to store or retrieve  InnoDB table data, encode the  -vvv memcached  option in the  daemon_memcached_option  configuration parameter in the MySQL configuration file. Examine the MySQL error log for debug output related to memcached  operations. 3388 [mysqld] [mysqld] ... loose-daemon_memcached_option=’-c 64’ # Linux shell>  ulimit -n 1024 shell>  ulimit -n 4096 shell>  ulimit -n 4096 # macOS shell>  ulimit -n 256 shell>  ulimit -n 4096 shell>  ulimit -n 4096 •If you encounter the following error in the MySQL error log, the server might fail to start: This section describes issues that you may encounter when using the  InnoDB memcached  plugin.