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学习spark

分析spark从两个纬度

  1. 框架层面 框架焦点在于处理流程,系统交互,性能等
  2. 数据流 数据流关注于数据的转换、合并、shuffle、结果

概念

  1. Master 中心节点,记录worker、Driver信息
  2. Worker 任务执行的节点,取Master发送的Driver,运行任务
  3. Client SparkSubmit启动,把用户的application(包含main的类)打包,分装成Driver, 提交给Master
  4. Driver Client向Master注册,Master随机取非满负荷的Worker,绑定Worker和此Driver,向此Worker发送任务消息

Cluster Programming Models distributed storage abstraction

备忘:scala 解释器 interactive

To recap previous chapter, RDDs provide the following facilities:

  • Immutable storage of arbitrary records across a cluster (in Spark, the records are Java objects).
  • Control over data partitioning, using a key for each record.
  • Coarse-grained operators that take into account partitioning. • Low latency due to in-memory storage.

As long as each batched record fits in the CPU cache, this leads to fast transformations and conversions.