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Posted to commits@cassandra.apache.org by "Jonathan Ellis (JIRA)" <ji...@apache.org> on 2011/04/04 18:20:06 UTC
[jira] [Commented] (CASSANDRA-1034) Remove assumption that Key to
Token is one-to-one
[ https://issues.apache.org/jira/browse/CASSANDRA-1034?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13015482#comment-13015482 ]
Jonathan Ellis commented on CASSANDRA-1034:
-------------------------------------------
I think we are almost done. A couple comments:
- DK.isEmpty seems like a bad method name for a Key object -- intuitively, keys are a specific point and should not contain other points except for the obvious identity case. Would isMinimum be a better name?
- I don't understand RP.toSplitValue or why DK would throw away information, when calling it. More generally, I'm unclear why we would have null keys in DK -- shouldn't you use a Token, if you don't have key information?
- using MINIMUM_TOKEN for both sort-before-everything and sort-after-everything values has always been confusing. Should we introduce a MAXIMUM_TOKEN value to clear that up?
> 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
> Assignee: Sylvain Lebresne
> Priority: Minor
> Fix For: 0.8
>
> Attachments: 0001-Generify-AbstractBounds.patch, 0001-Make-range-accept-both-Token-and-DecoratedKey.patch, 0002-LengthPartitioner.patch, 0002-Remove-assumption-that-token-and-keys-are-one-to-one-v2.patch, 0002-Remove-assumption-that-token-and-keys-are-one-to-one.patch, 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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