GitHub user XuMingmin opened a pull request:
https://github.com/apache/storm/pull/1863
fix: KafkaSpout is blocked in AutoCommitMode
What's the issue?
When Storm topology is run on 'At-Most-Once' mode, with ack executor=0,
KafkaSpout cannot emit records after some time.
What's the cause?
Function poll() controls whether it need to pull more data from Kafka
cluster. With the condition `!waitingToEmit() && numUncommittedOffsets <
maxUncommittedOffsets`, it's always `FALSE` after reaching threshold, as
`numUncommittedOffsets` is creasing and never reset on 'At-Most-Once' mode.
What's the solution?
I change the condition to `!waitingToEmit() && (numUncommittedOffsets <
maxUncommittedOffsets || consumerAutoCommitMode)`, that return `TRUE` with
AutoCommitMode regarding of UnCommittedOffset, see the comments inline.
Also, it's not required to track emitted(msgId) and numUncommittedOffsets
with AutoCommitMode .
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/XuMingmin/storm master
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/storm/pull/1863.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 #1863
----
commit f3c9985e26868fa52cee34335f70550c4f7744c4
Author: XuMingmin <[email protected]>
Date: 2017-01-05T19:31:42Z
fix: KafkaSpout is blocked in AutoCommitMode
What's the issue?
When Storm topology is run on 'At-Most-Once' mode, with ack executor=0,
KafkaSpout cannot emit records after some time.
What's the cause?
Function poll() controls whether it need to pull more data from Kafka
cluster. With the condition `!waitingToEmit() && numUncommittedOffsets <
maxUncommittedOffsets`, it's always `FALSE` after reaching threshold, as
`numUncommittedOffsets` is creasing and never reset on 'At-Most-Once' mode.
What's the solution?
I change the condition to `!waitingToEmit() && (numUncommittedOffsets <
maxUncommittedOffsets || consumerAutoCommitMode)`, that return `TRUE` with
AutoCommitMode regarding of UnCommittedOffset, see the comments inline.
Also, it's not required to track emitted(msgId) and numUncommittedOffsets
with AutoCommitMode .
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