map任务

实例运行缓慢，查看logview Map任务的并发量为105，但map任务的开始时间确是不一致的

源码分析根据《Hadoop2.6.0的FileInputFormat的任务切分原理分析（即如何控制FileInputFormat的map任务数量）》一文的内容，我们知道map任务的划分关键在于FileInputFormat的getSplits方法的实现策略，现在我们来看看其源码：public ...

分配了map任务的工作节点可以做什么？

记Hadoop2.5.0线上mapreduce任务执行map任务划分的一次问题解决

} } 我们看到TextInputFormat继承了FileInputFormat，因而根据《Hadoop2.6.0的FileInputFormat的任务切分原理分析（即如何控制FileInputFormat的map任务数量）》一文的内容，真正影响使用FileInputFormat的map任务划分的参数有：dfs.block...

Hadoop HDFS中的数据块和Map任务的分片

用hadoop fsck/-files-blocks 命令可以检查HDFS根目录(/)下所有文件，块的健康状况：Map任务的分片：为什么推荐Map任务的分片尺寸和HDFS基本块的大小一致为最佳呢？因为有3个因素：a.map任务数=输入文件总大小/分片尺寸，所以分片越大，map...

如何同时处理多个map任务的中间结果？

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