Github user mosermw commented on the issue:
https://github.com/apache/nifi/pull/2931
The JIRA ticket mentioned a dev list conversation where Oleg said it was to
limit the possibility of message loss in the event of a processor and/or NiFi
crash. However, it has proven to cause problems. I have tried to kill -9 NiFi
several times while ConsumeJMS is under heavy load and haven't lost a message,
though perhaps I've just been lucky. The javadoc of the session.recover method
doesn't seem to indicate that it should be called regularly.
The decision regarding what to do with this PR might become a risk
management one, where the benefits of session.recover as it is now are unknown
but the problems associated with it are known and significant.
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