Low Description
when using cqlsh tool to generate indexes, for example, suppose we have a column family Tuser, which has two columns: name and state.
cqlsh> create index name_key on Tuser(name);
cqlsh> create index name_key on Tuser(state);
note that name_key is used twice by mistake, then a javax.management.InstanceAlreadyExistsException will be thrown and this exception will prevent cassandra service from starting any more.