What does this error mean?
This error means a schema table has been corrupted in some form.
Why does this error occur?
This error happens when Cassandra does not find a partition column(s) when reading the schema of a table. Since this shouldn't be possible, it is indicative of a corruption of the schema table of some form. It may be as simple as a concurrent DROP and ALTER of a table.
How do you fix this error?
The full text of the error message outlines the steps to take. If the table should no longer exist (DROP), run the following query as outlined:
DELETE FROM <keyspace>.<table_name> WHERE keyspace_name = '<keyspace>' AND table_name = '<table>';
DELETE FROM <keyspace>.<table_name> WHERE keyspace_name = '<keyspace>' AND table_name = '<columns>';
If the table should exist, follow the restore procedures to restore the table from the backups directory.
To ignore the corruption issue, you can restart cassandra with