Benjamin Roth created CASSANDRA-13066:
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Summary: Fast repair with materialized views
Key: CASSANDRA-13066
URL: https://issues.apache.org/jira/browse/CASSANDRA-13066
Project: Cassandra
Issue Type: Improvement
Reporter: 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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