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https://issues.apache.org/jira/browse/NIFI-8207?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17416649#comment-17416649
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Peter Gyori commented on NIFI-8207:
-----------------------------------
Fixing counter behavior in the Wait/Notify pattern turned out to require:
* first *specifying the requirements* in cases that are not working with the
current implementation
* then *rewriting* the WaitNotifyProtocol *from scratch.*
Creating a correct releasableCount and reducedSignalCount calculation
apparently requires a complete redesign of the current implementation. It may
not be worth investing such effort into this as there are other patterns
already implemented in NiFi for similar use-cases.
> Counters in the Wait/Notify pattern do not work as expected
> -----------------------------------------------------------
>
> Key: NIFI-8207
> URL: https://issues.apache.org/jira/browse/NIFI-8207
> Project: Apache NiFi
> Issue Type: Bug
> Components: Extensions
> Reporter: Peter Gyori
> Assignee: Peter Gyori
> Priority: Major
> Labels: Wait/Notify
>
> The counters in the Wait/Notify pattern do not work as expected, the way
> counters are decremented seems to be wrong.
> A simple example to reproduce the issue:
> Let's use only one cache, identified by Release Signal ID "A".
> 1) Send 2 signals to cache "A", both with counter named "counter_1".
> 2) Also send 1 signal to cache "A" with counter named "counter_2".
> At this state, the cache looks like this:
> counter_1 -> 2
> counter_2 -> 1
> If we send 1 flowfile to the corresponding Wait processor, that looks for
> "counter_1" in cache "A", after the flowfile passes the Wait processor, the
> value of "counter_1" gets decremented to 0 instead of 1.
> It can be checked in debug mode. It can also be checked on the UI by sending
> another flowfile to the Wait processor and checking the value of the counter
> attributes that get appended to it.
> The problem seems to come from this line in the WaitNotifyProtocol class:
> {color:#000080}final long {color}reducedSignalCount = signalCount %
> requiredCountForPass;
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