> sudo su> /etc/cassandra/bin/cassandra -f and result....what is problem??----------------------------------------------------------------------------------------------------------------------------------------------------------------------------org.apache.avro.SchemaParseException: "strıng" is not a defined name. The type of the "name" field must be a defined name or a {"type": ...} expression. at org.apache.avro.Schema.parse(Schema.java:986) at org.apache.avro.Schema.parse(Schema.java:893) at org.apache.cassandra.db.DefsTable.loadFromStorage(DefsTable.java:90) at org.apache.cassandra.config.DatabaseDescriptor.loadSchemas(DatabaseDescriptor.java:502) at org.apache.cassandra.service.AbstractCassandraDaemon.setup(AbstractCassandraDaemon.java:180) at org.apache.cassandra.service.AbstractCassandraDaemon.activate(AbstractCassandraDaemon.java:356) at org.apache.cassandra.thrift.CassandraDaemon.main(CassandraDaemon.java:107)Exception encountered during startup: "strıng" is not a defined name. The type of the "name" field mu st be a defined name or a {"type": ...} expression.-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------