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https://issues.apache.org/jira/browse/CASSANDRA-13066?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Benjamin Roth reassigned CASSANDRA-13066:
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Assignee: Benjamin Roth
> Fast streaming with materialized views
> --------------------------------------
>
> Key: CASSANDRA-13066
> URL: https://issues.apache.org/jira/browse/CASSANDRA-13066
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Benjamin Roth
> Assignee: Benjamin Roth
>
> I propose adding a configuration option to send streams of tables with MVs
> not through the regular write path.
> This may be either a global option or better a CF option.
> Background:
> A repair of a CF with an MV that is much out of sync creates many streams.
> These streams all go through the regular write path to assert local
> consistency of the MV. This again causes a read before write for every single
> mutation which again puts a lot of pressure on the node - much more than
> simply streaming the SSTable down.
> In some cases this can be avoided. Instead of only repairing the base table,
> all base + mv tables would have to be repaired. But this can break eventual
> consistency between base table and MV. The proposed behaviour is always safe,
> when having append-only MVs. It also works when using CL_QUORUM writes but it
> cannot be absolutely guaranteed, that a quorum write is applied atomically,
> so this can also lead to inconsistencies, if a quorum write is started but
> one node dies in the middle of a request.
> So, this proposal can help a lot in some situations but also can break
> consistency in others. That's why it should be left upon the operator if that
> behaviour is appropriate for individual use cases.
> This issue came up here:
> https://issues.apache.org/jira/browse/CASSANDRA-12888?focusedCommentId=15736599&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-15736599
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