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ASF GitHub Bot commented on BEAM-115: ------------------------------------- GitHub user kennknowles opened a pull request: https://github.com/apache/incubator-beam/pull/147 [BEAM-115] Move expansion of Window.Bound into particular runners As per the [Runner API design](https://docs.google.com/document/d/1bao-5B6uBuf-kwH1meenAuXXS0c9cBQ1B2J59I3FiyI/edit?usp=sharing) this makes `Window.into` very explicitly a primitive, and moves the subsidiary primitives to top level classes in the `util/` (aka miscellaneous) directory, eventually to move to some appropriate final location for "runner utilities" or to be removed entirely. You can merge this pull request into a Git repository by running: $ git pull https://github.com/kennknowles/incubator-beam Window Alternatively you can review and apply these changes as the patch at: https://github.com/apache/incubator-beam/pull/147.patch To close this pull request, make a commit to your master/trunk branch with (at least) the following in the commit message: This closes #147 ---- commit d944b5e724dbc372969d83820a450134a031a21a Author: Kenneth Knowles <k...@google.com> Date: 2016-04-08T00:34:19Z Move expansion of Window.Bound into particular runners In the Beam model, windowing is a primitive concept. The expansion provided by the SDK is not implementable except via access to privileged methods not intended for Beam pipeline authors. This change is a precursor to eliminating these privileged entirely. ---- > Beam Runner API > --------------- > > Key: BEAM-115 > URL: https://issues.apache.org/jira/browse/BEAM-115 > Project: Beam > Issue Type: Improvement > Components: runner-core > Reporter: Kenneth Knowles > Assignee: Kenneth Knowles > > The PipelineRunner API from the SDK is not ideal for the Beam technical > vision. > It has technical limitations: > - The user's DAG (even including library expansions) is never explicitly > represented, so it cannot be analyzed except incrementally, and cannot > necessarily be reconstructed (for example, to display it!). > - The flattened DAG of just primitive transforms isn't well-suited for > display or transform override. > - The TransformHierarchy isn't well-suited for optimizations. > - The user must realistically pre-commit to a runner, and its configuration > (batch vs streaming) prior to graph construction, since the runner will be > modifying the graph as it is built. > - It is fairly language- and SDK-specific. > It has usability issues (these are not from intuition, but derived from > actual cases of failure to use according to the design) > - The interleaving of apply() methods in PTransform/Pipeline/PipelineRunner > is confusing. > - The TransformHierarchy, accessible only via visitor traversals, is > cumbersome. > - The staging of construction-time vs run-time is not always obvious. > These are just examples. This ticket tracks designing, coming to consensus, > and building an API that more simply and directly supports the technical > vision. -- This message was sent by Atlassian JIRA (v6.3.4#6332)