When migrating data from AWS RDS MySQL to TiDB using DM we got the following error:
Couldn't acquire global lock, snapshots will not be consistent: Access denied for user 'root'@'%' (using password: YES)
The TiDB documentation suggested the following configuration change for DM.
mydumpers:
global:
extra-args: "--no-locks"
However, the same doc mentioned the following:
If it is acceptable to not use FTWL to guarantee that the dump file is consistent with metadata or the upstream can pause writing data, you can skip the above error by adding the --no-locks argument for extra-args under mydumpers.
What are the practical implications of not using FTWL to guarantee that is the dump file is consistent with metadata?
For example, will this result in data loss? Or data corruption? Or slightly outdated database metrics?
The product doc referenced for the --no-locks argument is from v1.0 and not recommended. You may find the latest version of the documentation for migrating from Aurora to TiDB helpful.