c# - 定义有界容量的贪婪和非贪婪数据流 block 之间的区别

Question

我有一个BatchBlock，上面定义了BoundedCapacity

var _batchBlock = new BatchBlock<int>(2, new GroupingDataflowBlockOptions
                                      {BoundedCapacity = 100 });

因此，如果队列容量达到 100， block 将推迟收到的每条消息，直到有可用的位置。 在这种情况下，批处理队列是贪婪的还是非贪婪的？

Answer 1

该 block 是贪婪的，但不是因为它如何处理 100 以上的项目，而是 2 以下的项目。您可以将贪婪值设置为 false (true是默认值)，然后只有当有足够的元素可以发送一批时，该 block 才会实际消耗元素，直到那时它们才会被推迟:

var batchBlock = new BatchBlock<int>(2, new GroupingDataflowBlockOptions
{
    Greedy = false,
    BoundedCapacity = 100.
});

The BatchBlock class operates in either greedy or non-greedy mode. In greedy mode, which is the default, a BatchBlock object accepts every message that it is offered and propagates out an array after it receives the specified count of elements. In non-greedy mode, a BatchBlock object postpones all incoming messages until enough sources have offered messages to the block to form a batch

来自 Dataflow (Task Parallel Library)