问JanusGraph液滴抛出OperationTimedOutException

EN

     gremlin> JanusGraphFactory.drop(g);
        13:55:59 WARN  com.datastax.driver.core.RequestHandler  - Not retrying statement because it is not idempotent (this message will be logged only once). 
    Note that this version of the driver changes the default retry behavior for non-idempotent statements: they won't be automatically retried anymore.
   The driver marks statements non-idempotent by default, so you should explicitly call setIdempotent(true) if your statements are safe to retry.
            com.datastax.driver.core.exceptions.OperationTimedOutException: [/xxx.xxx.xxx.x:9042] Timed out waiting for server response
                    at com.datastax.driver.core.exceptions.OperationTimedOutException.copy(OperationTimedOutException.java:44)
                    at com.datastax.driver.core.exceptions.OperationTimedOutException.copy(OperationTimedOutException.java:26)
                    at com.datastax.driver.core.DriverThrowables.propagateCause(DriverThrowables.java:37)
                    at com.datastax.driver.core.DefaultResultSetFuture.getUninterruptibly(DefaultResultSetFuture.java:245)
                    at com.datastax.driver.core.AbstractSession.execute(AbstractSession.java:68)
                    at org.janusgraph.diskstorage.cql.CQLStoreManager.clearStorage(CQLStoreManager.java:334)
                    at org.janusgraph.diskstorage.Backend.clearStorage(Backend.java:589)
                    at org.janusgraph.core.JanusGraphFactory.drop(JanusGraphFactory.java:216)
                    at org.janusgraph.core.JanusGraphFactory$drop$0.call(Unknown Source)