[jira] [Commented] (GOSSIP-74) Critical bugs in FailureDetector

["Edward Capriolo (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/GOSSIP-74?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15924250#comment-15924250 ] 

Edward Capriolo commented on GOSSIP-74:
---------------------------------------

For case 1 I am not sure this matters. Only a host sends its own heartbeat so there can not be conflicting ones or ones with different delta's. a host records timestamp, sends delta, sleeps.

Case 2 seems reasonable it seems like a simple change.

> Critical bugs in FailureDetector
> --------------------------------
>
>                 Key: GOSSIP-74
>                 URL: https://issues.apache.org/jira/browse/GOSSIP-74
>             Project: Gossip
>          Issue Type: Bug
>            Reporter: Maxim Rusak
>            Assignee: Maxim Rusak
>
> Now FailureDetector have (at least) 2 bugs (in comparation to original paper):
> 1. latestHeartbeatMs don't update on each HeartBeat. So we have descriptiveStatistics consisted not from deltas between heartbeats but from time periods from first heartbeats.
> 2. when we create normalDistribution we pass variation, not standard deviation.
> They make FailureDetector totally indifferent due to extremely high deviation.
> Example: http://pastebin.com/xaeF52PP
> Here we send 100 heartbeats, one per second(for example), then we check the state after 2000 seconds, and comparing to threshold it's still alive.



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