hive orc压缩数据异常java.lang.ClassCastException: org.apache.hadoop.io.Text cannot be cast to org.apach...

 

hive表在建立时候指定存储格式

STORED AS ORC tblproperties ('orc.compress'='SNAPPY');

 

当insert数据到表时抛出异常

Caused by: java.lang.ClassCastException: org.apache.hadoop.io.Text cannot be cast to org.apache.hadoop.hive.ql.io.orc.OrcSerde$OrcSerdeRow at org.apache.hadoop.hive.ql.io.orc.OrcOutputFormat$OrcRecordWriter.write(OrcOutputFormat.java:98) at org.apache.hadoop.hive.ql.exec.FileSinkOperator.process(FileSinkOperator.java:743) at org.apache.hadoop.hive.ql.exec.Operator.forward(Operator.java:837) at org.apache.hadoop.hive.ql.exec.SelectOperator.process(SelectOperator.java:97) at org.apache.hadoop.hive.ql.exec.Operator.forward(Operator.java:837) at org.apache.hadoop.hive.ql.exec.TableScanOperator.process(TableScanOperator.java:115) at org.apache.hadoop.hive.ql.exec.MapOperator$MapOpCtx.forward(MapOperator.java:169) at org.apache.hadoop.hive.ql.exec.MapOperator.process(MapOperator.java:561)

 

此时查看表结构

desc formatted persons_orc;

       

能够看到SerDe Library 的格式是LazySimpleSerDe，序列化格式不是orc的,因此抛出异常

这里将表的序列化方式修改成orc便可

ALTER TABLE persons_orc SET FILEFORMAT ORC;

 

再看序列化格式已是orc，使用insert(insert overwrite table persons_orc select * from persons;)插入数据能够ok

 

 能够参考详细解释:http://www.imooc.com/article/252830