jackrabbit-oak-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Julian Reschke (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (OAK-2682) Introduce time difference detection for DocumentNodeStore
Date Thu, 13 Aug 2015 09:26:45 GMT

    [ https://issues.apache.org/jira/browse/OAK-2682?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14694942#comment-14694942
] 

Julian Reschke commented on OAK-2682:
-------------------------------------

Another thing I just realized: we need to be careful wrt taking action when we think there's
a problem. For instance, in the case of RDB, the people running the Oak instance may not have
any administrative control over the DB server, so actually might be unable to "fix" the problem.
Maybe we really need to track the differences for each cluster node in the persistence, and
only take action after comparing the *differences*. 

> Introduce time difference detection for DocumentNodeStore
> ---------------------------------------------------------
>
>                 Key: OAK-2682
>                 URL: https://issues.apache.org/jira/browse/OAK-2682
>             Project: Jackrabbit Oak
>          Issue Type: Improvement
>          Components: core, mongomk, rdbmk
>            Reporter: Stefan Egli
>            Assignee: Stefan Egli
>              Labels: resilience
>             Fix For: 1.3.4
>
>         Attachments: OAK-2682.patch, rdbservertime.diff
>
>
> Currently the lease mechanism in DocumentNodeStore/mongoMk is based on the assumption
that the clocks are in perfect sync between all nodes of the cluster. The lease is valid for
60sec with a timeout of 30sec. If clocks are off by too much, and background operations happen
to take couple seconds, you run the risk of timing out a lease. So introducing a check which
WARNs if the clocks in a cluster are off by too much (1st threshold, eg 5sec?) would help
increase awareness. Further drastic measure could be to prevent a startup of Oak at all if
the difference is for example higher than a 2nd threshold (optional I guess, but could be
20sec?).



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message