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Posted to commits@cassandra.apache.org by "Duncan Sands (JIRA)" <ji...@apache.org> on 2014/01/17 16:23:21 UTC
[jira] [Commented] (CASSANDRA-6600) Huge read latency with
LOCAL_ONE when < RF nodes are up
[ https://issues.apache.org/jira/browse/CASSANDRA-6600?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13874851#comment-13874851 ]
Duncan Sands commented on CASSANDRA-6600:
-----------------------------------------
The cqlsh testing procedure is incorrect (sorry for the mistake), so for the moment I can't eliminate the possibility that the problem is in the client. I will try to reduce the problem to something reproducible over the next few days.
> Huge read latency with LOCAL_ONE when < RF nodes are up
> -------------------------------------------------------
>
> Key: CASSANDRA-6600
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6600
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Reporter: Duncan Sands
> Assignee: Michael Shuler
>
> I recently upgraded a multi data centre cluster from 1.2.12 to 2.0.4.
> In one data centre there are 3 nodes with an RF of 3. Clients are reading from these nodes using CQL3 and LOCAL_ONE. At one point during the upgrade 1 node was down, so less than RF nodes were up. Read latency went from < 1ms to > 1 second. Once all nodes were up, read latency went back down to < 1ms. If I stop a node then read latency shoots back up again.
> This is not due to my client as I was able to reproduce this as follows. With all RF nodes up:
> connect to a node using cqlsh
> set the consistency level to LOCAL_ONE
> use cqlsh to read a few values from a random table - it completes instantly
> bring down one of the other nodes in the same data centre
> do the same query again in cqlsh. It times out with "Request did not complete within rpc_timeout".
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