Help Center/ Data Replication Service/ Troubleshooting/ Solutions to Failed Check Items/ Database Parameters/ Checking Whether the Values of group_concat_max_len Are Consistent
Updated on 2024-11-30 GMT+08:00
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Checking Whether the Values of group_concat_max_len Are Consistent

If the values of group_concat_max_len in the source and destination databases are different, the queried fields may be truncated. Change the parameter values to the same.

Failure Cause

The group_concat_max_len values of the source and destination databases must be the same.

Handling Suggestion

Change the value of group_concat_max_len of the source database to be the same as that of the destination database.
  • If the database is a self-managed MySQL database, run commands to change the value.
    1. Run the following command to check the value: 
      SHOW VARIABLES LIKE "group_concat_max_len";
    2. Run the following command to change the value: 
      SET SESSION group_concat_max_len = <New maximum length>
  • If the database is an RDS for MySQL DB instance, change the value of the group_concat_max_len parameter by referring to Modifying Parameters of an RDS for MySQL Instance.

For details about how to change the value of group_concat_max_len for other types of databases, see the usage guide of the corresponding database.

Parent topic: Database Parameters