[jira] [Resolved] (CASSANDRA-3775) rpc_timeout error when reading from a cluster that just had a node die. Only happens if gossip hasn't noticed the dead node yet.

["Jonathan Ellis (Resolved) (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/CASSANDRA-3775?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Jonathan Ellis resolved CASSANDRA-3775.
---------------------------------------

    Resolution: Not A Problem

This is expected behavior. Cassandra only sends one data request for each query, so if that replica is dead-but-not-detected-dead then the request will time out.
                
> rpc_timeout error when reading from a cluster that just had a node die. Only happens if gossip hasn't noticed the dead node yet.
> --------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: CASSANDRA-3775
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-3775
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>    Affects Versions: 1.0.6
>         Environment: ubuntu. Used ccm to create the cluster.
>            Reporter: Tyler Patterson
>
> Create a cluster of 3 nodes with RF=3 and CL=QUORUM. Insert some data then kill a node (not the coordinator) and immediately try to read the data. The read request will fail within about 2 seconds. cassandra.yaml has rpc_timeout=10000. A failing test has been written in cassandra-dtest, branch "read_when_node_is_down". The test can be run like this: nosetests --nocapture read_when_node_down_test.py Here is the error from the test:
> {code}
> ======================================================================
> ERROR: read_when_node_down_test.TestReadWhenNodeDown.read_when_node_down_test
> ----------------------------------------------------------------------
> Traceback (most recent call last):
>   File "/usr/lib/pymodules/python2.7/nose/case.py", line 187, in runTest
>     self.test(*self.arg)
>   File "/home/tahooie/cassandra-dtest/read_when_node_down_test.py", line 40, in read_when_node_down_test
>     query_c1c2(cursor, 100, CL)
>   File "/home/tahooie/cassandra-dtest/tools.py", line 28, in query_c1c2
>     cursor.execute('SELECT c1, c2 FROM cf USING CONSISTENCY %s WHERE key=k%d' % (consistency, key))
>   File "/usr/local/lib/python2.7/dist-packages/cql/cursor.py", line 96, in execute
>     raise cql.OperationalError("Request did not complete within rpc_timeout.")
> OperationalError: ('Request did not complete within rpc_timeout.', 'reading failed in 2.0130 seconds.')
> {code}
> I did notice that if I sleep 20 seconds after killing the node and before reading, that the read succeeds. This is probably because gossip has had a chance to notice that the node is down.

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