[jira] [Created] (BEAM-6906) Mutating accumulators in fused stages is generally unsafe - need to provide a single mutable accumulator

["Kenneth Knowles (JIRA)" <ji...@apache.org>]

Kenneth Knowles created BEAM-6906:
-------------------------------------

             Summary: Mutating accumulators in fused stages is generally unsafe - need to provide a single mutable accumulator
                 Key: BEAM-6906
                 URL: https://issues.apache.org/jira/browse/BEAM-6906
             Project: Beam
          Issue Type: Test
          Components: beam-model
            Reporter: Kenneth Knowles
            Assignee: Yueyang Qiu


Our current docs encourage a CombineFn author to mutate accumulators for efficiency. This is important, but cannot be done generally without losing efficiency - it is not safe to share accumulators within a stage or across sliding windows. The ownership story needs to be clear. Any accumulator that is mutable is from that point on owned by the CombineFn, not the runner and cannot be given to other steps.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)