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  • 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

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  • 原文地址:https://www.cnblogs.com/xjh713/p/10137880.html
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