You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@beam.apache.org by "Kenneth Knowles (JIRA)" <ji...@apache.org> on 2016/12/21 21:16:58 UTC
[jira] [Updated] (BEAM-653) Refine specification for
WindowFn.isCompatible()
[ https://issues.apache.org/jira/browse/BEAM-653?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Kenneth Knowles updated BEAM-653:
---------------------------------
Component/s: beam-model-runner-api
> Refine specification for WindowFn.isCompatible()
> -------------------------------------------------
>
> Key: BEAM-653
> URL: https://issues.apache.org/jira/browse/BEAM-653
> 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 WindowFn.
> 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 anyhow)
> - 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
(v6.3.4#6332)