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https://issues.apache.org/jira/browse/CASSANDRA-13165?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16143206#comment-16143206
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Jeff Jirsa commented on CASSANDRA-13165:
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I suspect the short version is something like this:
Replica A,B,C gets CQL row 1 @ TS=1
Replica A goes offline.
Replica B, C gets CQL row 2 @ TS=2
Replica A comes up, replica B goes down
Replica A, C get CQL row 3 @ TS=3
Replica B comes up, replica C goes down
Replica A, B get CQL row 4 @ TS=4
You do a SELECT, and you get timestamps 1,3, 4 from A, 1,2, 4 FROM B, 1,2,3
from C. If A is the coordinator, it has all of the winning timestamps for its
three rows, but it doesn't know that it's missing a row. When the digest
mismatch happens, it still needs to do a full data read to realize it's missing
row 2.
> Read repair process.
> --------------------
>
> Key: CASSANDRA-13165
> URL: https://issues.apache.org/jira/browse/CASSANDRA-13165
> Project: Cassandra
> Issue Type: Wish
> Components: Coordination
> Reporter: Andrey
> Priority: Minor
>
> Why can't we send timestamps together with digests? It will reduce
> unnecessary communications between coordinator and replicas. I think the size
> of messages is not that matter here, because a latency( due to network) is
> way more harmful.
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