Duncan Sands created CASSANDRA-6600:
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Summary: 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
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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