some question about isChainable

[Marvin777]

Hi all:

We all know that the conditions for chaining are 9, like this:

However, I have a question about 2, 3, 8 in the figure above.
As far as I know, the operator cannot be null, and If the partitioner of the edge is forward, then their parallelism must be the same. Maybe I'm completely missing something...

Waiting for your reply.

Best regard.

[Aljoscha Krettek]

I think this might just be overly cautious because it's not incorrect to check these. Also, in fact I think you could have "forward" with differing parallelism in some earlier versions which would lead to some unexpected results. Not sure if that is still possible now.

> On 24. Jan 2018, at 09:50, Marvin777 <[hidden email]> wrote:
>
> Hi all:
>
> We all know that the conditions for chaining are 9, like this:
> <image.png>
> However, I have a question about 2, 3, 8 in the figure above.
> As far as I know, the operator cannot be null, and If the partitioner of the edge is forward, then their parallelism must be the same. Maybe I'm completely missing something...
>
> Waiting for your reply.
>
> Best regard.

[Marvin777]

Thank you for your reply. I've learned.

Note that, with a local debug of Flink 1.3.1, i found that restrictions have been added in addEdgeInternal(), like this:

Best regard.

2018-01-25 1:17 GMT+08:00 Aljoscha Krettek <[hidden email]>:

I think this might just be overly cautious because it's not incorrect to check these. Also, in fact I think you could have "forward" with differing parallelism in some earlier versions which would lead to some unexpected results. Not sure if that is still possible now.

> On 24. Jan 2018, at 09:50, Marvin777 <[hidden email]> wrote:
>
> Hi all:
>
> We all know that the conditions for chaining are 9, like this:
> <image.png>

> However, I have a question about 2, 3, 8 in the figure above.
> As far as I know, the operator cannot be null, and If the partitioner of the edge is forward, then their parallelism must be the same. Maybe I'm completely missing something...
>
> Waiting for your reply.
>
> Best regard.