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https://issues.apache.org/jira/browse/ARTEMIS-5241?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Clebert Suconic closed ARTEMIS-5241.
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> Remove useless validation for cluster-connection confirmation-window-size
> -------------------------------------------------------------------------
>
> Key: ARTEMIS-5241
> URL: https://issues.apache.org/jira/browse/ARTEMIS-5241
> Project: ActiveMQ Artemis
> Issue Type: Bug
> Affects Versions: 2.39.0
> Reporter: Justin Bertram
> Assignee: Justin Bertram
> Priority: Major
> Labels: pull-request-available
> Fix For: 2.40.0
>
> Time Spent: 20m
> Remaining Estimate: 0h
>
> When a Core client reconnects to a broker it may resend packets which it had
> already sent but to which it had not yet received a reply. The number of
> packets resent depends on the {{confirmationWindowSize}}.
> If the resent packets include a client message then that might result in a
> duplicate message on the broker. To mitigate this risk we have duplicate
> detection. The broker will compare a special ID set on incoming messages to a
> cache of IDs which it has already received. The size of this broker-size
> cache is configured via {{id-cache-size}}.
> Putting these two things together one can see how the configuration of
> {{confirmationWindowSize}} and {{id-cache-size}} need to be coordinated to
> ensure no messages are duplicated. For example, if the
> {{confirmationWindowSize}} is so large that it holds more client messages
> than the {{id-cache-size}} the duplicates may occur.
> The method {{checkoutDupCacheSize}} on
> {{org.apache.activemq.artemis.core.config.impl.ConfigurationImpl}} is meant
> to help with this coordination for cluster connections, but this method
> appears to be useless for at least two reasons:
> # It compares the configuration of the cluster-connection's confirmation
> window size with the {{id-cache-size}} of the _local_ broker. However, the
> {{id-cache-size}} of the local broker is meaningless for the
> cluster-connection. It would need to compare the confirmation window size
> with the {{id-cache-size}} of the _remote_ broker to actually coordinate
> effectively.
> # It has a bug which causes spurious {{WARN}} messages like this to be logged:
> {quote}WARN [org.apache.activemq.artemis.core.server] (Thread-1
> (ActiveMQ-client-global-threads)) AMQ224078: The size of duplicate cache
> detection (<id_cache-size/>) appears to be too large 2,000. It should be no
> greater than the number of messages that can be squeezed into confirmation
> window buffer (<confirmation-window-size/>) 10,485,760.{quote}
> # In order to calculate how many client messages might be in the confirmation
> window the logic uses a relatively arbitrary "default" message size. However,
> if the actual size of the messages is different from this then the {{WARN}}
> message will be incorrect and unhelpful.
> Considering all this the {{checkoutDupCacheSize}} method and all directly
> related code should be removed.
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