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From "Jonathan Ellis (JIRA)" <j...@apache.org>
Subject [jira] Commented: (CASSANDRA-1034) Remove assumption that Key to Token is one-to-one
Date Wed, 10 Nov 2010 21:14:13 GMT

    [ https://issues.apache.org/jira/browse/CASSANDRA-1034?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12930778#action_12930778
] 

Jonathan Ellis commented on CASSANDRA-1034:
-------------------------------------------

Okay, so that is a problem because we create DK(Token, null) internally for range queries
currently even when using the key-based API.

Once that is fixed I'm fine with saying "the first 10" (or if more convenient, "that's undefined"),
since only Hadoop or similar iterate-over-everything approaches should be using Token-based
range queries at the API level.  (Again, I'm assuming that there are enough tokens to achieve
sufficient granularity, iow, that the number of rows sharing a token is less than the InputSplit
size.)

> Remove assumption that Key to Token is one-to-one
> -------------------------------------------------
>
>                 Key: CASSANDRA-1034
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-1034
>             Project: Cassandra
>          Issue Type: Bug
>            Reporter: Stu Hood
>            Priority: Minor
>         Attachments: 1034_v1.txt
>
>
> get_range_slices assumes that Tokens do not collide and converts a KeyRange to an AbstractBounds.
For RandomPartitioner, this assumption isn't safe, and would lead to a very weird heisenberg.
> Converting AbstractBounds to use a DecoratedKey would solve this, because the byte[]
key portion of the DecoratedKey can act as a tiebreaker. Alternatively, we could make DecoratedKey
extend Token, and then use DecoratedKeys in places where collisions are unacceptable.

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