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https://issues.apache.org/jira/browse/CASSANDRA-12653?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15884235#comment-15884235
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Jason Brown commented on CASSANDRA-12653:
-----------------------------------------
[~spod] I'm on board with {{firstSynSendAt}} being a timestamp, I'm just
questioning what you compare it against. Instead of this:
{code}
long ts = epStateMap.values().iterator().next().getUpdateTimestamp();
if ((ts - Gossiper.instance.firstSynSendAt) < 0 ||
Gossiper.instance.firstSynSendAt == 0)
{code}
I'm suggesting this:
{code}
if ((System.nanoTime() - Gossiper.instance.firstSynSendAt) < 0 ||
Gossiper.instance.firstSynSendAt == 0)
{code}
It amounts to the same thing (a check against {{System.nanoTime()}}), but it's
more obvious where the value comes from.
[~jkni] wrt to {{synchronized}}, on one hand agree with you, but then that
makes the argument for making many more of the methods on {{Gossiper}}
synchronized. If we're going to make this method different from the rest (which
is fine with me), can we add in a relevant, detailed comment why it is?
> In-flight shadow round requests
> -------------------------------
>
> Key: CASSANDRA-12653
> URL: https://issues.apache.org/jira/browse/CASSANDRA-12653
> Project: Cassandra
> Issue Type: Bug
> Components: Distributed Metadata
> Reporter: Stefan Podkowinski
> Assignee: Stefan Podkowinski
> Priority: Minor
> Fix For: 2.2.x, 3.0.x, 3.11.x, 4.x
>
>
> Bootstrapping or replacing a node in the cluster requires to gather and check
> some host IDs or tokens by doing a gossip "shadow round" once before joining
> the cluster. This is done by sending a gossip SYN to all seeds until we
> receive a response with the cluster state, from where we can move on in the
> bootstrap process. Receiving a response will call the shadow round done and
> calls {{Gossiper.resetEndpointStateMap}} for cleaning up the received state
> again.
> The issue here is that at this point there might be other in-flight requests
> and it's very likely that shadow round responses from other seeds will be
> received afterwards, while the current state of the bootstrap process doesn't
> expect this to happen (e.g. gossiper may or may not be enabled).
> One side effect will be that MigrationTasks are spawned for each shadow round
> reply except the first. Tasks might or might not execute based on whether at
> execution time {{Gossiper.resetEndpointStateMap}} had been called, which
> effects the outcome of {{FailureDetector.instance.isAlive(endpoint))}} at
> start of the task. You'll see error log messages such as follows when this
> happend:
> {noformat}
> INFO [SharedPool-Worker-1] 2016-09-08 08:36:39,255 Gossiper.java:993 -
> InetAddress /xx.xx.xx.xx is now UP
> ERROR [MigrationStage:1] 2016-09-08 08:36:39,255 FailureDetector.java:223
> - unknown endpoint /xx.xx.xx.xx
> {noformat}
> Although is isn't pretty, I currently don't see any serious harm from this,
> but it would be good to get a second opinion (feel free to close as "wont
> fix").
> /cc [~Stefania] [~thobbs]
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