impala error

impala:
[nobida145:21000] > select * from a;
Query: select * from a
ERROR: AnalysisException: Failed to load metadata for table: default.a
CAUSED BY: TableLoadingException: Failed to load metadata for table: a
CAUSED BY: TTransportException: null
[nobida145:21000] >

hive :

2014-11-03 11:04:32,306 ERROR [pool-4-thread-77]: server.TThreadPoolServer (TThreadPoolServer.java:run(251)) - Thrift error occurred during processing of message.
org.apache.thrift.protocol.TProtocolException: Cannot write a TUnion with no set value!
        at org.apache.thrift.TUnion$TUnionStandardScheme.write(TUnion.java:240)
        at org.apache.thrift.TUnion$TUnionStandardScheme.write(TUnion.java:213)
        at org.apache.thrift.TUnion.write(TUnion.java:152)
        at org.apache.hadoop.hive.metastore.api.ColumnStatisticsObj$ColumnStatisticsObjStandardScheme.write(ColumnStatisticsObj.java:550)
        at org.apache.hadoop.hive.metastore.api.ColumnStatisticsObj$ColumnStatisticsObjStandardScheme.write(ColumnStatisticsObj.java:488)
        at org.apache.hadoop.hive.metastore.api.ColumnStatisticsObj.write(ColumnStatisticsObj.java:414)
        at org.apache.hadoop.hive.metastore.api.TableStatsResult$TableStatsResultStandardScheme.write(TableStatsResult.java:388)
        at org.apache.hadoop.hive.metastore.api.TableStatsResult$TableStatsResultStandardScheme.write(TableStatsResult.java:338)
        at org.apache.hadoop.hive.metastore.api.TableStatsResult.write(TableStatsResult.java:288)
        at org.apache.hadoop.hive.metastore.api.ThriftHiveMetastore$get_table_statistics_req_result$get_table_statistics_req_resultStandardScheme.write(ThriftHiveMetastore.java)
        at org.apache.hadoop.hive.metastore.api.ThriftHiveMetastore$get_table_statistics_req_result$get_table_statistics_req_resultStandardScheme.write(ThriftHiveMetastore.java)
        at org.apache.hadoop.hive.metastore.api.ThriftHiveMetastore$get_table_statistics_req_result.write(ThriftHiveMetastore.java)
        at org.apache.thrift.ProcessFunction.process(ProcessFunction.java:53)
        at org.apache.thrift.TBaseProcessor.process(TBaseProcessor.java:39)
        at org.apache.hadoop.hive.metastore.TSetIpAddressProcessor.process(TSetIpAddressProcessor.java:48)
        at org.apache.thrift.server.TThreadPoolServer$WorkerProcess.run(TThreadPoolServer.java:244)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:744)



原因不详，跟建的表名和列名相同有关？