Cassandra副本给出错误“ NoneType”对象，没有属性“终止”

Question

我正在尝试使用复制命令从csv文件将数据加载到Cassandra表中，该文件在字段中包含一些空值。我收到以下错误：

cqlsh:voicecdrs> COPY voicecdrs.voicecdrs_201912 from 'test1.csv' with delimiter =','
  and header=True;
Using 15 child processes

Starting copy of voicecdrs.voicecdrs_201912 with columns [Calling, Called,
   ChargingDateAndTime, CDRFileName, ChargeableTimeUnits, First_CellIdentity,
   GuideNumber, IMEI, IncomingRoute, LRNValue, Last_CellIdentity, MSCID,
   Network_Call_Reference, OutgoingRoute, RecordName, SMSCCENTRE].
[Errno 11] Resource temporarily unavailable
'NoneType' object has no attribute 'terminate'