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https://issues.apache.org/jira/browse/CASSANDRA-840?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12842847#action_12842847
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Gary Dusbabek commented on CASSANDRA-840:
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>It's safe for other threads to be messing about with existing Table references
>during a mutate right?
No. It's very unsafe. ThreadA calls Table.open(A), ThreadB drops a CF in A,
ThreadA then tries to mutate rows on that CF. At some point ThreadB will cause
that table to release() and its column families go away. I'm not sure what the
right behavior is in this case (loud failure IMO). That table essentially
becomes invalid and will be replaced in Table.instances with a new version.
Is that a bad approach? Possibly. I was hoping to avoid having to discover
all the states in CFS that I would have to account for when a CF def is
mutated. CFS wasn't designed from that standpoint and I think getting it there
would be an onerous task.
I think a fair compromise would be to mark Table instances invalid when they
are released and have them throw an exception in apply() to indicate the
reference has been invalidated and can no longer be operated on (I'm thinking
in the context of renames, which are the most complicated, but this approach
makes the most sense in the context of deletes).
> Add the ability to add/remove/rename column families on a single node.
> ----------------------------------------------------------------------
>
> Key: CASSANDRA-840
> URL: https://issues.apache.org/jira/browse/CASSANDRA-840
> Project: Cassandra
> Issue Type: Sub-task
> Components: Core
> Reporter: Gary Dusbabek
> Assignee: Gary Dusbabek
> Priority: Minor
> Fix For: 0.7
>
> Attachments: v1-0001-store-cfid-map-in-CLH.txt,
> v1-0002-establish-ordering-of-cfids.txt,
> v1-0003-add-a-cf-on-a-single-node.txt,
> v1-0004-drop-a-cf-on-a-single-node.txt,
> v1-0005-rename-a-cf-on-a-single-node.txt,
> v1-0006-alternate-locking-approach.txt
>
>
> We need the ability to manipulate the KS/CF definitions structures in
> DatabaseDescriptor.
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