MySQL/TDSQL for MySQL/TDSQL-C Check Details

• Check requirements: the innodb_stats_on_metadata environment variable in the source database must be set to OFF.
• • Check description:
    • If the innodb_stats_on_metadata parameter is enabled, every time tables in the information_schema metadatabase are queried, InnoDB will update the information_schema.statistics table, causing slower access. After this parameter is disabled, access to the schema table can be faster.
    • On MySQL versions below 5.6.6, the default value of the innodb_stats_on_metadata parameter is ON, and you need to change it to OFF. On MySQL 5.6.6 or above, the default value is OFF, which has no problem.

Fix

Note：

You can modify this parameter without restarting the database, but you need to close all business connections to the database. If the source database is a slave, you also need to restart the master/slave sync SQL thread to prevent current business connections from continuing writing data in the mode before modification.

1. Log in to the source database.
2. Change the value of innodb_stats_on_metadata to OFF.

   set global innodb_stats_on_metadata = OFF 
   

3. Check whether the configuration takes effect.

   show global variables like "%innodb_stats_on_metadata%";
   

   The system should display a result similar to the following:

mysql> show globle table status like '%innodb_stats_on_metadata%';
+--------------------------+-------+
| Variable_name            | Value |
+--------------------------+-------+
| innodb_stats_on_metadata | OFF   |
+--------------------------+----- -+
1 row in set (0.00 sec)

4. Run the verification task again.