slot migration error

[stillerrr]

Redis uses the ASKING command to force nodes which status is IMPORTING to write keys that do not belong to the node when doing slot migration.
If an error occurs during the migration, and the migration is interrupted, the already written keys can no longer be found, the keys can be found in the RDB file, but if you use command to query these keys, it would report these keys belong to the other node, and return nil after redirection.

[stillerrr]

If the key is a complex data type, it may occupy a large amount of memory, leading to uneven memory usage on the nodes of cluster.