Question

我有一个MR作业，它写入多行，每行一列。虽然我为列名传递了一个非null值，但我得到以下异常

java.io.IOException：InvalidRequestException（why：column name不能为空）在org.apache.cassandra.hadoop.ColumnFamilyRecordWriter $ RangeClient.run（ColumnFamilyRecordWriter.java:307）引起：InvalidRequestException（原因：列名不能为空）在org.apache.cassandra.thrift.Cassandra $ batch_mutate_result.read（Cassandra.java:19477）在org.apache.cassandra.thrift.Cassandra $ Client.recv_batch_mutate（Cassandra.java:1035）在org.apache.cassandra.thrift.Cassandra $ Client.batch_mutate（Cassandra.java:1009）在org.apache.cassandra.hadoop.ColumnFamilyRecordWriter $ RangeClient.run（ColumnFamilyRecordWriter.java:299）

我在这里有什么东西吗？

这是我写过的减速机 -

公共静态类SampleReducer扩展了Reducer＆gt; { static Logger logger = LoggerFactory.getLogger（AndroidEthnicityMap.class）;

            @Override
            protected void reduce(Text key, Iterable<Text> values, Context context) throws IOException ,InterruptedException {
                    String tStr[] = key.toString().split("__");
                    logger.info("The string to be reduced is " + key.toString());
                    String appid = tStr[0];
                    String columnName = tStr[1];
                    String columnValue = "{}";
                    if(values.iterator().hasNext())
                            columnValue = values.iterator().next().toString();



                    ByteBuffer bbcn = ByteBufferUtil.bytes(columnName);
                    ByteBuffer bbcv = ByteBufferUtil.bytes(columnValue);
                    ByteBuffer bbkey = ByteBufferUtil.bytes(appid);

                    Mutation m = new Mutation();
                    m.setColumn_or_supercolumn(new ColumnOrSuperColumn());
                    Column c = new Column();
                    c.setName(ByteBufferUtil.bytes(columnName));
                    c.setValue(ByteBufferUtil.bytes(columnValue));
                    c.setTimestamp(System.currentTimeMillis());
                    m.column_or_supercolumn.setColumn(c);

                    Mutation[] marray = new Mutation[]{m};
                    context.write(ByteBufferUtil.bytes(appid), Arrays.asList(marray));

            }
    }

Answer 1

“空”表示“非空，零长度”。这不是有效的列名。

Answer 2

将日志添加到reducer以查看它转移到上下文的所有列名称。看来你的列族是一个空字符串。记录所有数据不仅是colName

写入Cassandra Column系列时Hadoop MR作业失败“InavlidRequestException（列名不能为空）”

2 个答案: