go - 缓冲 channel 是否维持秩序？

Question

在 Go 中，缓冲 channel 是否有顺序保证？

例如:你有两个 goroutines A & B 共享一个 channel 。 A 将数据推送到 channel 上，而 B 从中读取数据。你保证 B 会按照 A 放入 channel 的相同顺序读取数据吗？

我知道如果有多个生产者或消费者，顺序可能是不确定的，但我特别想问的是只有 1 个生产者和 1 个消费者。

Answer 1

"Are you guaranteed that B will read data In the same order that A put it into the channel?"

是的。保证数据的顺序。
但是交付仅对无缓冲 channel 有保证，没有缓冲。
(请参阅此答案的第二部分)

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您可以从 The Nature Of Channels In Go 中看到“William Kennedy”中说明的 channel 概念。 (2014 年 2 月):它显示了如何遵守顺序或读/写。
另见 Channels :

Receivers always block until there is data to receive.

• If the channel is unbuffered, the sender blocks until the receiver has received the value.
• If the channel has a buffer, the sender blocks only until the value has been copied to the buffer; if the buffer is full, this means waiting until some receiver has retrieved a value.

无缓冲 channel

缓冲 channel

^{图片来源:Ardan labs - William Kennedy}

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同一位 William Kennedy 在“ The Behavior Of Channels ”(2017 年 10 月)中详细介绍了交付保证方面的内容

Do I need a guarantee that the signal sent by a particular goroutine has been received?

^{图片来源:同样，Ardan labs - William Kennedy}

The three channel options are Unbuffered, Buffered >1 or Buffered =1.

• Guarantee

  • An Unbuffered channel gives you a Guarantee that a signal being sent has been received.
    • Because the Receive of the signal Happens Before the Send of the signal completes.

• No Guarantee

  • A Buffered channel of size >1 gives you No Guarantee that a signal being sent has been received.
    • Because the Send of the signal Happens Before the Receive of the signal completes.

• Delayed Guarantee

  • A Buffered channel of size =1 gives you a Delayed Guarantee. It can guarantee that the previous signal that was sent has been received.
    • Because the Receive of the First Signal, Happens Before the Send of the Second Signal completes.