Troubleshoot migration issues between different versions

Available in VPC

In using Database Migration Service, you may encounter the following problems. View the causes and solutions of problems and take proper action:

Compatibility issue

When migrating from the lower version of MySQL/MariaDB to the higher version, compatibility issue occurs.

Cause

It is recommended to migrate between the same Major versions but you can use Database Migration Service even when the versions of Source DB and Target DB are different. For example, you can migrate from the MySQL 5.7 version to the MySQL 8.0 version. However, the MySQL/MariaDB version that reached EOL can cause compatibility-related error messages during migration.

Solution

Check the version of Source DB MySQL/MariaDB to migrate is not retired. If the MySQL/MariaDB version is retired, it can cause compatibility-related error messages during migration.

Error when migrating from Source DB MySQL version 5.7 and MariaDB version 10.1 or later to Target DB MySQL version 8.0

Error occurs when migrating from Source DB MySQL version 5.7 and MariaDB version 10.1 or later to Target DB MySQL version 8.0.

Cause

sql_mode='NO_AUTO_CREATE_USER' setting, which is supported by MySQL 5.7 and MariaDB 10.1.7 and later versions as Default value, is not supported starting with MySQL 8.0.

Solution

• If sql_mode='NO_AUTO_CREATE_USER' setting is applied to Source DB, delete and migrate. If the error found during executing Import, delete migration and retry.
• Backup method: when selecting mydumper, error related to sql_mode does not occur.
• Confirm whether there is any compatibility issue between the existing application and MySQL 8.0 before switching services.

Replication consistency issues with MySQL 5.7.40

Replication consistency issues occur in MySQL version 5.7.40.

Cause

MySQL 5.7.40 version can have mysqldump bug due to its own MySQL specification, which can cause replication consistency issues.

Solution

It is recommended that you choose the mydumper method or set Target DB to a version other than MySQL 5.7.40.

"Collations unsupported in Target DB are included." Error Message

"Collations unsupported in Target DB are included." The error message appears.

Cause

It is an error message that occurs if the Source DB uses the MySQL 8.0 version and the Target DB uses 5.7 or an earlier version. "utf8mb4_0900_ai_ci," the default collation supported by the MySQL 8.0 version, is not supported in the 5.7 version.

Solution

Change Collation options in the Source DB, such as Database, Table, View, Procedure, and Function, before migration.