jackrabbit-oak-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Tomek Rękawek (JIRA) <j...@apache.org>
Subject [jira] [Commented] (OAK-2106) Optimize reads from secondaries
Date Wed, 04 Nov 2015 09:24:27 GMT

    [ https://issues.apache.org/jira/browse/OAK-2106?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14989192#comment-14989192

Tomek Rękawek commented on OAK-2106:

After discussing with Marcel I tried a different approach, in which the Oak instance connect
directly to all secondary instances and reads their _lastRev for the root. Then it's able
to check if the secondary instance contains an up-to-date parent and - therefore - if the
request document can be read from the nearest Mongo instance.

Pull request:

Patch file:

> Optimize reads from secondaries
> -------------------------------
>                 Key: OAK-2106
>                 URL: https://issues.apache.org/jira/browse/OAK-2106
>             Project: Jackrabbit Oak
>          Issue Type: Improvement
>          Components: core, mongomk
>            Reporter: Marcel Reutegger
>            Assignee: Marcel Reutegger
>              Labels: performance, scalability
> OAK-1645 introduced support for reads from secondaries under certain
> conditions. The current implementation checks the _lastRev on a potentially
> cached parent document and reads from a secondary if it has not been
> modified in the last 6 hours. This timespan is somewhat arbitrary but
> reflects the assumption that the replication lag of a secondary shouldn't
> be more than 6 hours.
> This logic should be optimized to take the actual replication lag into
> account. MongoDB provides information about the replication lag with
> the command rs.status().

This message was sent by Atlassian JIRA

View raw message