Thank you Reuven for the answers. I see that the answers are mostly Runner 
dependent, does it mean, BEAM as SDK, does not specify the intended behavior 
and it delegates to each runner to interpret the expected behavior?

Thanks,
Ke

> On Feb 17, 2021, at 11:48 AM, Reuven Lax <[email protected]> wrote:
> 
> 
> 
> On Wed, Feb 17, 2021 at 11:25 AM Ke Wu <[email protected] 
> <mailto:[email protected]>> wrote:
> Hello everyone,
> 
> Is there any documentation on the implication of name param when applying a 
> PTransform on PCollection? Some questions I have on mind is
> 
> Is the name required to be unique across the pipeline?
> No - only needs to be unique within the current scope. 
> For stateful PTransforms such as stateful ParDo, Combine and Window, if no 
> name is provided, is state preserved during upgrades?
> Runner dependent, but generally the name is required to perform upgrades.
>  
> If a stable name is provided,  is state preserved during upgrades?
> Runner dependent, but often yes. 
> If a stable name is provided and changed intentionally during upgrade, is 
> state expected to be clearer?
> Again runner dependent, but for the dataflow runner you currently can pass in 
> a name mapping that maps the old name to the new one. 
> 
> Thanks,
> Ke
> 
> 

Reply via email to