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From "Tyler Hobbs (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (CASSANDRA-6439) Token ranges are erroneously swapped
Date Fri, 10 Jan 2014 18:14:53 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-6439?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13868065#comment-13868065
] 

Tyler Hobbs commented on CASSANDRA-6439:
----------------------------------------

This isn't specific to Murmur3Partitioner.  CASSANDRA-5089 added more validation to the start/end
combinations, and specifically, disallows a (start_key, end_token) wrapping range combination.
 There doesn't seem to be a technical reason for this limitation, so I would guess that we
could support combination that with some minor adjustments.

> Token ranges are erroneously swapped
> ------------------------------------
>
>                 Key: CASSANDRA-6439
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-6439
>             Project: Cassandra
>          Issue Type: Bug
>          Components: Core
>            Reporter: Francesco Piccinno
>            Priority: Critical
>             Fix For: 2.0.0
>
>
> I am trying to achieve a linear scan on the data contained in a cassandra node by exploiting
tokens. The idea behind my approach is to request through the pycassa SystemManager a list
of tokens that the cluster is responsible of, and then for each token, issue a {{key_range}}
command specifying {{start}} and {{end}} interval. The problem is that apparently some tokens
returned by the server does not respect the property {{start}} < {{end}}. I think that
the bug is due to the fact that {{Murmur3RandomPartitioner}} is used, but I am just guessing
here.
> Anyway here are the steps to reproduce the bug:
> {code:title=Triggering the bug}
> $ pycassaShell -k KEYSPACE
> In [1]: tokens = map(lambda x: (int(x.start_token), int(x.end_token)), SYSTEM_MANAGER.describe_ring('KEYSPACE'))
> In [2]: len(filter(lambda x: x[0] < x[1], tokens))
> Out[2]: 255
> In [3]: len(filter(lambda x: x[0] > x[1], tokens))
> Out[3]: 1
> In [4]: filter(lambda x: x[0] > x[1], tokens)
> Out[4]: [(9207458196362321348, -9182599474778206823)]
> In [5]: for i in CF.get_range(start_token="9207458196362321348", finish_token="-9182599474778206823"):
print i
> # ...
> # after some objects are printed
> # ...
> InvalidRequestException: InvalidRequestException(why="Start key's token sorts after end
token")
> {code}



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