cassandra-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Duncan Sands (JIRA)" <>
Subject [jira] [Commented] (CASSANDRA-6600) Huge read latency with LOCAL_ONE when < RF nodes are up
Date Tue, 25 Mar 2014 16:12:18 GMT


Duncan Sands commented on CASSANDRA-6600:

Fair enough: it's not actionable as is.  I've so far failed to reproduce it outside of production,
but there's definitely something funny going on.

> Huge read latency with LOCAL_ONE when < RF nodes are up
> -------------------------------------------------------
>                 Key: CASSANDRA-6600
>                 URL:
>             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

This message was sent by Atlassian JIRA

View raw message