我使用Hadoop的Cassandra进行输入和输出。在输出减少作业期间，我得到了一个错误:
2011-08-10 03:54:04,326 WARN org.apache.hadoop.mapred.Child: Error running child
java.io.IOException: InvalidRequestException(why:[MyKeyspace][MyColumnFamily][66756c6c74657874] = [6c696e6bb66e68656974207a756d.................65697465726520536f6e67746578746520] failed validation (String didn't validate.))
at org.apache.cassandra.thrift.Cassandra$batch_mutate_result.read(Cassandra.java:19045)
at org.apache.cassandra.thrift.Cassandra$Client.recv_batch_mutate(Cassandra.java:1035)
at org.apache.cassandra.thrift.Cassandra$Client.batch_mutate(Cassandra.java:1009)
at org.apache.cassandra.hadoop.ColumnFamilyRecordWriter$RangeClient.run(ColumnFamilyRecordWriter.java:285)
2011-08-10 03:54:04,339 INFO org.apache.hadoop.mapred.Task: Runnning cleanup for the task
2011-08-10 03:54:04,340 WARN org.apache.hadoop.io.UTF8: truncating long string: 267364 chars, starting with java.io.IOException:
根据日志，这不是在开始时发生的，而是在成功合并、排序和处理8981个键之后发生的。第8982次失败
已经在google和stackoverflow上搜索过了，但是没有找到
列族如下:
create column family MyColumnFamily with comparator = UTF8Type and
key_validation_class=UTF8Type and
column_metadata =
[
{column_name: column1, validation_class: UTF8Type, index_type: 0},
{column_name: column2, validation_class: UTF8Type, index_type: 0},
{column_name: column3, validation_class: UTF8Type, index_type: 0}
];
提前感谢!
这意味着其中一个列值实际上不是有效的utf8编码字符串。消息中的第一个十六进制字符串是以字节为单位的列名，第二个字符串是无法解码的字节。