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https://issues.apache.org/jira/browse/CASSANDRA-13073?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ZhaoYang updated CASSANDRA-13073:
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Component/s: Materialized Views
> Optimize repair behaviour with MVs
> ----------------------------------
>
> Key: CASSANDRA-13073
> URL: https://issues.apache.org/jira/browse/CASSANDRA-13073
> Project: Cassandra
> Issue Type: Bug
> Components: Materialized Views
> Reporter: Benjamin Roth
>
> I am referring to a discusson on the dev list about the MV streaming issues
> discussed in 12888.
> It turned out that under some circumstances, repairing MVs can lead to
> inconsistencies. To remove that inconsistencies, it is necessary, to repair
> the base table first and then the MV again. These inconsistencies can be
> created both by read repair or CF/Keyspace repair.
> Proposition:
> - Exclude MVs from keyspace repairs
> - Disable read repairs on MVs or transform them to a read repair of the base
> table (maybe complicated but possible)
> Explanation:
> - CF base has PK a and field b
> - MV has PK a, b
> - 2 nodes n1 + n2, no hints
> - Initial state is a=1,b=1 at time t=0
> - Node n2 goes down
> - Mutation a=1, b=2 at time t=1
> - Node n2 comes up and node n1 goes down
> - Mutation a=1, b=3 at time t=2
> - Node n1.mv contains: a1=1, b=3 + tombstone for a1=1,b=1
> - Node n2.mv contains: a1=1, b=2 + tombstone for a1=1,b=1
> When doing a repair on mv _before_ repairing base, mv would look like:
> - Node n1.mv contains: a1=1, b=3 + tombstone for a1=1,b=1 + a1=1, b=2
> - Node n2.mv contains: a1=1, b=2 + tombstone for a1=1,b=1 + a1=1, b=3
> Repairing _only_ the base table would create the correct result:
> - Node n1.mv contains: a1=1, b=3 + tombstone for a1=1,b=1 + tombstone for
> a1=1,b=2
> - Node n2.mv contains: a1=1, b=3 + tombstone for a1=1,b=1 (TS for a1=2,b=2
> should not have been created as b=3 was there, which shadows b=2 and should
> not reach the MV at all)
> All this does not apply if CASSANDRA-13066 will be implemented and enabled
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