Dataflow 2.1.0中是否有IntrabundleParalleization的替代方案? [英] Is there an alternative to IntrabundleParallelization in Dataflow 2.1.0?

问题描述

根据数据流2.X的发行说明，删除了IntraBundleParallelization.有没有一种方法可以控制/增加数据流2.1.0上DoFns的并行性?

According to release notes of dataflow 2.X, IntraBundleParallelization is removed. Is there a way to control/increase parallelism of DoFns on dataflow 2.1.0 ?

当我在1.9.0版本的数据流上使用IntrabundleParallelization时，性能得到了改善.

I was getting better performance when I used IntrabundleParallelization on 1.9.0 version of dataflow.

推荐答案

已将其删除，因为在调用完成后，其实现会在ProcessElement调用的ProcessContext上保留一个句柄，因此这是不安全的，并且不能保证工作.

It was removed because its implementation keeps a handle on the ProcessContext of a ProcessElement call after the call completes, and this is unsafe and not guaranteed to work.

但是，我同意这是一个有用的抽象，很不幸，我们还没有替代品.

However, I agree that it was a useful abstraction, and it is unfortunate that we don't have a replacement yet.

作为解决方法，您可以尝试以下操作:

As a workaround, you can try the following:

• 在您的DoFn的@Setup中，创建具有所需线程数的Executor
• 在您的DoFn的@StartBundle中，创建一个包装执行程序的ExecutorCompletionService
• 在@ProcessElement中，向其提交Future，代表处理元素的结果
• 在@ProcessElement中，也poll() CompletionService表示已完成的期货并输出其结果
• 在@FinishBundle中，等待所有剩余的期货完成，输出其结果，然后关闭CompletionService.

• In your DoFn's @Setup, create an Executor with the needed number of threads
• In your DoFn's @StartBundle, create an ExecutorCompletionService wrapping the executor
• In @ProcessElement, submit a Future to it representing the result of processing the element
• In @ProcessElement, also poll() the CompletionService for completed futures and output their results
• In @FinishBundle, wait for all remaining futures to complete, output their results, and shut down the CompletionService.

请记住不在您的期货中使用ProcessContext. ProcessContext只能在当前线程和当前ProcessElement调用中使用.

Remember to not use the ProcessContext in your futures. ProcessContext can only be used from the current thread and from within the current ProcessElement call.

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