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https://issues.apache.org/jira/browse/ARTEMIS-3766?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17518514#comment-17518514
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Iliya Grushevskiy commented on ARTEMIS-3766:
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It seems that expiration information of the message on B should be removed (or
moved to different property) during mirroring, because B should just reflect
state of A and not control it. However once A is no longer available B will not
perform same operations on messages as A would. But it seems more reasonable
than trying to replicate both state and behavior of source and even after
loosing A one can examine left messages on that custom ttl property and set
actual ttl.
> Race condition with Dual Mirror and Expiry
> ------------------------------------------
>
> Key: ARTEMIS-3766
> URL: https://issues.apache.org/jira/browse/ARTEMIS-3766
> Project: ActiveMQ Artemis
> Issue Type: Bug
> Affects Versions: 2.21.0
> Reporter: Stephen Baker
> Priority: Major
>
> When dual mirroring is in play there is a race condition which can result in
> missing or duplicate messages on the brokers.
>
> Scenario 1:
> # Bring up two artemis instances with broker-connection mirroring between
> each other. (A and B)
> # Send a message to A with a short TTL (I used 30 seconds in my test)
> # After the message mirrors but before it expires, pause the Mirror queue on
> both sides
> # Wait for the message to expire, and the reaper thread to pick it up
> # Observe that on both sides the message has moved to the ExpiryQueue. In
> the Mirror queue there are 2 messages on A (a message destined to the
> ExpiryQueue and an ack on the original message). On B there is a single
> message in the mirror, which is the message to the expiry queue.
> # Resume the mirror, I'm not sure the order matters, but I did B and then A.
> # Observe that on A there is a single message in the ExpiryQueue, but on B
> there are now 2 messages in the expiry queue.
> Scenario 2:
> # Bring up two artemis instances with broker-connection mirroring between
> each other. (A and B). On A disable the reaper thread by setting
> `<message-expiry-scan-period>-1</message-expiry-scan-period>`
> # Send a message to A with a short TTL
> # Wait for the TTL to expire
> # On B the message moves to the ExpiryQueue, on A the message ends
> disappears (no longer in the ExpiryQueue nor the original queue)
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