[
https://issues.apache.org/jira/browse/ZOOKEEPER-2418?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Flavio Junqueira updated ZOOKEEPER-2418:
----------------------------------------
Assignee: Nicholas Wolchko
> txnlog diff sync can skip sending some transactions to followers
> ----------------------------------------------------------------
>
> Key: ZOOKEEPER-2418
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2418
> Project: ZooKeeper
> Issue Type: Bug
> Components: server
> Affects Versions: 3.5.1
> Reporter: Nicholas Wolchko
> Assignee: Nicholas Wolchko
> Priority: Critical
> Original Estimate: 168h
> Remaining Estimate: 168h
>
> If the leader is having disk issues so that its on disk txnlog is behind the
> in memory commit log, it will send a DIFF that is missing the transactions in
> between the two.
> Example:
> There are 5 hosts in the cluster. 1 is the leader. 5 is disconnected.
> We commit up to zxid 1000.
> At zxid 450, the leader's disk stalls, but we still commit transactions
> because 2,3,4 are up and acking writes.
> At zxid 1000, the txnlog on the leader has 1-450 and the commit log has
> 500-1000.
> Then host 5 regains its connection to the cluster and syncs with the leader.
> It will receive a DIFF containing zxids 1-450 and 500-1000.
> This is because queueCommittedProposals in the LearnerHandler just queues
> everything within its zxid range. It doesn't give an error if there is a gap
> between peerLastZxid and the iterator it is queueing from.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
