Daniel Meyer created CASSANDRA-6229:
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Summary: transfers never occur after enabling a shuffle
Key: CASSANDRA-6229
URL: https://issues.apache.org/jira/browse/CASSANDRA-6229
Project: Cassandra
Issue Type: Bug
Components: Tools
Reporter: Daniel Meyer
Using the following documentation as reference:
http://www.datastax.com/documentation/cassandra/2.0/webhelp/cassandra/tools/toolsCassandraShuffle.html
After running the 'shuffle en' step, the command does not block giving the
indication that a transfer has occurred. However, running 'shuffle ls' at an
arbitrary time after enabling the shuffle results in a large list of pending
transfers. From the users perspective it is unclear what is happening;
however, it looks like the transfer does not actually occur.
repro steps:
1) cd to latest cassandra-2.0 branch
2) ccm create shuffle_test
3 ccm populate -n 3
4) delete the 'num_tokens' line from each cassandra.yaml file for all three
nodes.
5) ccm start
6) run 'ccm node1 ring' and verify the vnodes are not enabled.
7) ccm node1 stress -o insert
8) for each node set 'num_tokens: 256' in the cassandra.yaml
9) restart the nodes
10) run 'ccm node1 ring' to verify vnodes is enabled
11) ccm node1 shuffle create
12) ccm node1 shuffle en
13) wait arbitrary amount of time and run 'ccm node1 shuffle ls'.
Expected: transfers should eventually happen and not be observed with 'shuffle
ls'
Actual: transfers never seem to occur. If in fact they do occur it is not
obvious.
If transfers do in fact occur it is very difficult to tell. This was initially
discovered on a real cluster and the cluster sat overnight without any
transfers happening. As a user I would also expect 'shuffle en' to block. The
non blocking behavior does not seem ideal from a user perspective.
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