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https://issues.apache.org/jira/browse/CASSANDRA-580?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12794444#action_12794444
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Kelvin Kakugawa commented on CASSANDRA-580:
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potential incompatibility w/ IColumn and IColumnContainer interfaces.
The key issue is that Column and SuperColumn rely on timestamps to indicate
when deletion should occur. In particular, through these methods:
getMarkedForDeleteAt()
mostRecentLiveChangeAt()
A separate, less interesting, issue is that SuperColumn auto-assumes Column for
its sub-column serializer.
Right now, I've put together a new class, VersionColumn, that's context-based.
I've added context() methods to IColumn and added some instanceof checks.
However, I'm still exploring the implementation for the delete logic.
atm, I'm trying to avoid having to add a SuperVersionColumn class. However,
what is an interesting way to define the version "context" of a SuperColumn?
An aggregated context of all the sub-columns may be worth exploring.
Alternatively, since all the updates are timestamped, we could use that as a
rough approximation for mostRecentLiveChangeAt(), but that seems to break the
spirit of versioned contexts.
> vector clock support
> --------------------
>
> Key: CASSANDRA-580
> URL: https://issues.apache.org/jira/browse/CASSANDRA-580
> Project: Cassandra
> Issue Type: New Feature
> Components: Core
> Environment: N/A
> Reporter: Kelvin Kakugawa
> Assignee: Kelvin Kakugawa
> Attachments: 580-context-v1.patch, 580-context-v2.patch,
> 580-context-v3.patch, 580-interface-1-add-vector-clock.diff,
> 580-interface-2-add-vector-clock.diff, 580-thrift-v3.patch,
> 580-thrift-v4.patch, 580-thrift-v5.patch
>
> Original Estimate: 672h
> Remaining Estimate: 672h
>
> Allow a ColumnFamily to be versioned via vector clocks, instead of long
> timestamps. Purpose: enable incr/decr; flexible conflict resolution.
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