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https://issues.apache.org/jira/browse/BEAM-1612?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15999920#comment-15999920
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Kenneth Knowles commented on BEAM-1612:
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This is probably already obvious and taken into account in all of this
discussion, but I want to raise deliberately that the requirement on bundling
is one-way:
- it is required that there is a finish bundle / flush call in between
processing an element and including it in a checkpoint
- it is not required to actually checkpoint with each flush
So unless I have miscalculated, I do think it is fine to set a timer and
periodically call "finish bundle" and then only include those elements that
preceded it as part of the checkpoint, if such bookkeeping is reasonable. I
can't comment on the other ideas.
> Support real Bundle in Flink runner
> -----------------------------------
>
> Key: BEAM-1612
> URL: https://issues.apache.org/jira/browse/BEAM-1612
> Project: Beam
> Issue Type: Improvement
> Components: runner-flink
> Reporter: Jingsong Lee
>
> The Bundle is very important in the beam model. Users can use the bundle to
> flush buffer, can reuse many heavyweight resources in a bundle. Most IO
> plugins use the bundle to flush.
> Moreover, FlinkRunner can also use Bundle to reduce access to the FlinkState,
> such as first placed in JavaHeap, flush into RocksDbState when invoke
> finishBundle , this can reduce the number of serialization.
> But now FlinkRunner calls the finishBundle every processElement. We need
> support real Bundle.
> I think we can have the following implementations:
> 1.Invoke finishBundle and next startBundle in {{snapshot}} of Flink. But
> sometimes this "Bundle" maybe too big. This depends on the user's checkpoint
> configuration.
> 2.Manually control the size of the bundle. The half-bundle will be flushed to
> a full-bundle by count or eventTime or processTime or {{snapshot}}. We do not
> need to wait, just call the startBundle and finishBundle at the right time.
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