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 Tue, 11 Aug 2015 15:34:45 GMT

    [ https://issues.apache.org/jira/browse/OAK-2682?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14681953#comment-14681953
] 

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

I just did some experiments:

- all DBs tested support CURRENT_TIMESTAMP, but they differ in their default resolution (we
need milliseconds) but also in their support for specifying the precision, thus we'll unfortunately
will have to make this vendor-specific

- it would be preferable if the DocumentStore implementation wouldn't need to make assumptions
about what table and row to query (as far as I can tell, I need *some* object to query to
make this work). How about adding the (Collection collection, String id) to the method signature?
(this would also make things clearer with multiplexing store impls)

> 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
>            Reporter: Stefan Egli
>            Assignee: Stefan Egli
>              Labels: resilience
>             Fix For: 1.3.5
>
>         Attachments: OAK-2682.patch
>
>
> 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