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https://issues.apache.org/jira/browse/CASSANDRA-1391?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13149767#comment-13149767
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Jonathan Ellis commented on CASSANDRA-1391:
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bq. As all of the migrations are user initiated we can easily calculate what
modifications migration makes and propagate only them
Yes, that's implied by moving to a CF-based structure I think.
bq. keeping TimeUUID as ID of the migration to identify "apply" order
I don't see why you'd want to complicate things by doing this. We already have
perfectly good per-column conflict resolution without it.
bq. it would be very useful to have the logic abstracted from schemas so it can
be used for other use cases
I'm okay in principle with introducing a EveryNodeReplicationStrategy but
refactoring migrations to that is a separate step from this ticket.
> Allow Concurrent Schema Migrations
> ----------------------------------
>
> Key: CASSANDRA-1391
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1391
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Affects Versions: 0.7.0
> Reporter: Stu Hood
> Assignee: Pavel Yaskevich
> Fix For: 1.1
>
> Attachments: CASSANDRA-1391.patch
>
>
> CASSANDRA-1292 fixed multiple migrations started from the same node to
> properly queue themselves, but it is still possible for migrations initiated
> on different nodes to conflict and leave the cluster in a bad state. Since
> the system_add/drop/rename methods are accessible directly from the client
> API, they should be completely safe for concurrent use.
> It should be possible to allow for most types of concurrent migrations by
> converting the UUID schema ID into a VersionVectorClock (as provided by
> CASSANDRA-580).
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