fails to copy row_keys table because non-nullable field data_type of the Cassandra DB contains null values

[tarzanek]

migrate from Cassandra 3.11.13 to ScyllaDB, the schema is from KairosDB, migrator fails to copy row_keys table because non-nullable field data_type of the Cassandra DB contains null values (error: RuntimeException: The 3th field 'data_type' of input row cannot be null)

is there a workaround?

[tarzanek]

generally we can add a null check into preparation of the data for writing, but it is weird a non-nullable column contains nulls
does Cassandra have some way to either repair or scrub the data?
(ala https://docs.scylladb.com/stable/operating-scylla/nodetool-commands/scrub.html )