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https://issues.apache.org/jira/browse/CASSANDRA-13700?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Joel Knighton updated CASSANDRA-13700:
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Status: Patch Available (was: In Progress)
> Heartbeats can cause gossip information to go permanently missing on certain
> nodes
> ----------------------------------------------------------------------------------
>
> Key: CASSANDRA-13700
> URL: https://issues.apache.org/jira/browse/CASSANDRA-13700
> Project: Cassandra
> Issue Type: Bug
> Components: Distributed Metadata
> Reporter: Joel Knighton
> Assignee: Joel Knighton
> Priority: Critical
>
> In {{Gossiper.getStateForVersionBiggerThan}}, we add the {{HeartBeatState}}
> from the corresponding {{EndpointState}} to the {{EndpointState}} to send.
> When we're getting state for ourselves, this means that we add a reference to
> the local {{HeartBeatState}}. Then, once we've built a message (in either the
> Syn or Ack handler), we send it through the {{MessagingService}}. In the case
> that the {{MessagingService}} is sufficiently slow, the {{GossipTask}} may
> run before serialization of the Syn or Ack. This means that when the
> {{GossipTask}} acquires the gossip {{taskLock}}, it may increment the
> {{HeartBeatState}} version of the local node as stored in the endpoint state
> map. Then, when we finally serialize the Syn or Ack, we'll follow the
> reference to the {{HeartBeatState}} and serialize it with a higher version
> than we saw when constructing the Ack or Ack2.
> Consider the case where we see {{HeartBeatState}} with version 4 when
> constructing an Ack and send it through the {{MessagingService}}. Then, we
> add some piece of state with version 5 to our local {{EndpointState}}. If
> {{GossipTask}} runs and increases the {{HeartBeatState}} version to 6 before
> the {{MessageOut}} containing the Ack is serialized, the node receiving the
> Ack will believe it is current to version 6, despite the fact that it has
> never received a message containing the {{ApplicationState}} tagged with
> version 5.
> I've reproduced in this in several versions; so far, I believe this is
> possible in all versions.
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