[jira] [Created] (BEAM-12118) QueuingBeamFnDataClient adds polling latency to completing bundle processing

["Sam Whittle (Jira)" <ji...@apache.org>]

Sam Whittle created BEAM-12118:
----------------------------------

             Summary: QueuingBeamFnDataClient adds polling latency to completing bundle processing
                 Key: BEAM-12118
                 URL: https://issues.apache.org/jira/browse/BEAM-12118
             Project: Beam
          Issue Type: Bug
          Components: java-fn-execution
            Reporter: Sam Whittle
            Assignee: Sam Whittle


Currently the inboundDataClients are registered with recieve, and they add data to a queue. There is no explicit indication from the clients that they are no longer going to add values to the queue.

Within QueueingBeamFnDataClient.drainAndBlock the queue is therefore polled and if nothing is present all clients are polled to see if they are complete.

This design makes for unfortunate tradeoffs on poll timeout:
- cpu wasted with small timeout
- additional latency in noticing we have completed with larger timeout

With the existing InboundDataClient interface, we could have a separate thread call awaitCompletion on all of the clients and then shutdown the queue (adding a poison pill perhaps)
Or we could modify InboundDataClient interface to allow registering iterest in when the client is done producing elements.  The existing clients all seem based upon futures which allow that.








--
This message was sent by Atlassian Jira
(v8.3.4#803005)