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

hive表在创建时候指定存储格式

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;

可以看到SerDe Library 的格式是LazySimpleSerDe，序列化格式不是orc的,所以抛出异常

这里将表的序列化方式修改为orc即可

ALTER TABLE persons_orc SET FILEFORMAT ORC;

再看序列化格式已经是orc，使用insert(insert overwrite table persons_orc select * from persons;)插入数据可以ok

可以参考详细解释:http://www.imooc.com/article/252830