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https://issues.apache.org/jira/browse/CASSANDRA-4288?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13845638#comment-13845638
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Tyler Hobbs commented on CASSANDRA-4288:
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bq. Quentin Conner cited 30-40 samples as being statistically significant,
although I'm not sure where that number comes from either.
That's only for a statistically significant measurement of variance for FD
purposes. I terms of gossip, we're relying on other nodes already having made
accurate FD judgements, so what Chris has here should be sufficient.
bq. I used 5s as the min wait instead of 15s. I don't really care if that's a
constant or fraction or RING_DELAY or whatever color people like best.
A constant is fine, but just to fit within the project coding style, these
should probably be {{static final int GOSSIP_SETTLE_MIN_WAIT_MS}}, etc.
Minor comments on the code:
* The warning log should only happen after {{gossipSettlePollSuccessRequired}}
rounds of checking.
* You can use variadic arguments for the warning log instead of an array
* totalPolls should be incremented prior to the warning log
* You can just throw a RuntimeException after catching the InterruptedException
Other than that, I think it's good.
> prevent thrift server from starting before gossip has settled
> -------------------------------------------------------------
>
> Key: CASSANDRA-4288
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4288
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Peter Schuller
> Assignee: Chris Burroughs
> Fix For: 2.0.4
>
> Attachments: CASSANDRA-4288-trunk.txt, j4288-1.2-v1-txt
>
>
> A serious problem is that there is no co-ordination whatsoever between gossip
> and the consumers of gossip. In particular, on a large cluster with hundreds
> of nodes, it takes several seconds for gossip to settle because the gossip
> stage is CPU bound. This leads to a node starting up and accessing thrift
> traffic long before it has any clue of what up and down. This leads to
> client-visible timeouts (for nodes that are down but not identified as such)
> and UnavailableException (for nodes that are up but not yet identified as
> such). This is really bad in general, but in particular for clients doing
> non-idempotent writes (counter increments).
> I was going to fix this as part of more significant re-writing in other
> tickets having to do with gossip/topology/etc, but that's not going to
> happen. So, the attached patch is roughly what we're running with in
> production now to make restarts bearable. The minimum wait time is both for
> ensuring that gossip has time to start becoming CPU bound if it will be, and
> the reason it's large is to allow for down nodes to be identified as such in
> most typical cases with a default phi conviction threshold (untested, we
> actually ran with a smaller number of 5 seconds minimum, but from past
> experience I believe 15 seconds is enough).
> The patch is tested on our 1.1 branch. It applies on trunk, and the diff is
> against trunk, but I have not tested it against trunk.
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