beam-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Daniel Halperin (JIRA)" <>
Subject [jira] [Commented] (BEAM-653) Refine specification for WindowFn.isCompatible()
Date Mon, 03 Apr 2017 16:48:41 GMT


Daniel Halperin commented on BEAM-653:

Is it important to resolve this before first stable release?

> Refine specification for WindowFn.isCompatible() 
> -------------------------------------------------
>                 Key: BEAM-653
>                 URL:
>             Project: Beam
>          Issue Type: New Feature
>          Components: beam-model, beam-model-runner-api
>            Reporter: Kenneth Knowles
> {{WindowFn#isCompatible}} doesn't really have a spec. In practice, it is used primarily
when flattening together multiple PCollections. All of the WindowFns must be compatible, and
then just a single WindowFn is selected arbitrarily for the output PCollection.
> In consequence, downstream of the Flatten, the merging behavior will be taken from this
> Currently, there are some mismatches:
>  - Sessions with different gap durations _are_ compatible today, but probably shouldn't
be since merging makes little sense. (The use of tiny proto-windows is an implementation detail
>  - SlidingWindows and FixedWindows _could_ reasonably be compatible if they had the same
duration, though it might be odd.
> Either way, we should just nail down what we actually mean so we can arrive at a verdict
in these cases.

This message was sent by Atlassian JIRA

View raw message