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https://issues.apache.org/jira/browse/CASSANDRA-5665?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jonathan Ellis updated CASSANDRA-5665:
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Reviewer: jbellis (was: brandon.williams)
Currently the logic in applyStateLocally is (essentially)
{code}
if (remoteGeneration > localGeneration)
handleMajorStateChange(ep, remoteState);
else if ( remoteGeneration == localGeneration ) // generation
has not changed, apply new states
applyNewStates(ep, localEpStatePtr, remoteState);
{code}
You're changing hMSTC to be more like applyNewStates, can we combine the two
instead?
> Gossiper.handleMajorStateChange can lose existing node ApplicationState
> -----------------------------------------------------------------------
>
> Key: CASSANDRA-5665
> URL: https://issues.apache.org/jira/browse/CASSANDRA-5665
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Affects Versions: 1.2.5
> Reporter: Jason Brown
> Assignee: Jason Brown
> Priority: Minor
> Labels: gossip, upgrade
> Fix For: 1.2.6, 2.0 beta 1
>
> Attachments: 5665-v1.diff
>
>
> Dovetailing on CASSANDRA-5660, I discovered that further along during an
> upgrade, when more nodes are on the new major version, a node the previous
> version can get passed some incomplete Gossip info about another, already
> upgraded node, and the older node drops AppStat info about that node.
> I think what happens is that a 1.1 node (older rev) gets gossip info from a
> 1.2 node (A), which includes incomplete (lacking some AppState data) gossip
> info about another 1.2 node (B). The 1.1 node, which has marked incorrectly
> kicked node B out of gossip due to the bug described in #5660, then takes
> that incomplete node B info and wholesale replaces any previous known state
> about node B in Gossiper.handleMajorStateChanged. Thus, if we previously had
> DC/RACK info, it'll get dropped as part of the
> endpointStateMap.put(endpointstate). When the data being pased is incomplete,
> 1.1 will start referencing node B and gets into the NPE situation in #5498.
> Anecdotally, this bad state is short-lived, less than a few minutes, even as
> short as ten seconds, until gossip catches up and properly propagates the
> AppState data. Furthermore, when upgrading a two datacenter, 48 node cluster,
> it only occurred on two nodes for less than a minute each. Thus, the scope
> seems limited but can occur.
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