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https://issues.apache.org/jira/browse/CASSANDRA-12888?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15897523#comment-15897523
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T Jake Luciani edited comment on CASSANDRA-12888 at 3/6/17 3:44 PM:
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Proposing another (maybe simpler solution to this problem):
We currently replay the base table mutations through the write path and drop
the streamed table.
Instead of this we could use the streamed base table with repairedAt flag like
any other repair.
Then, just as we do now replay the mutations through the write path, only
create a mutation flag that only updates the MVs and not the base table.
This means the MV wouldn't be incrementally repairable but really you shouldn't
need to repair the MVs unless there is dataloss.
was (Author: tjake):
Proposing another (maybe simpler solution to this problem):
We currently replay the base table mutations through the write path and drop
the streamed table.
Instead of this we could keep the streamed based table with repairedAt flag
and drop it in.
Then, just as we do now replay the mutations through the write path, only
create a mutation flag that only updates the MVs and not the base table.
> Incremental repairs broken for MVs and CDC
> ------------------------------------------
>
> Key: CASSANDRA-12888
> URL: https://issues.apache.org/jira/browse/CASSANDRA-12888
> Project: Cassandra
> Issue Type: Bug
> Components: Streaming and Messaging
> Reporter: Stefan Podkowinski
> Assignee: Benjamin Roth
> Priority: Critical
> Fix For: 3.0.x, 3.11.x
>
>
> SSTables streamed during the repair process will first be written locally and
> afterwards either simply added to the pool of existing sstables or, in case
> of existing MVs or active CDC, replayed on mutation basis:
> As described in {{StreamReceiveTask.OnCompletionRunnable}}:
> {quote}
> We have a special path for views and for CDC.
> For views, since the view requires cleaning up any pre-existing state, we
> must put all partitions through the same write path as normal mutations. This
> also ensures any 2is are also updated.
> For CDC-enabled tables, we want to ensure that the mutations are run through
> the CommitLog so they can be archived by the CDC process on discard.
> {quote}
> Using the regular write path turns out to be an issue for incremental
> repairs, as we loose the {{repaired_at}} state in the process. Eventually the
> streamed rows will end up in the unrepaired set, in contrast to the rows on
> the sender site moved to the repaired set. The next repair run will stream
> the same data back again, causing rows to bounce on and on between nodes on
> each repair.
> See linked dtest on steps to reproduce. An example for reproducing this
> manually using ccm can be found
> [here|https://gist.github.com/spodkowinski/2d8e0408516609c7ae701f2bf1e515e8]
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