Aleksey Yeschenko created CASSANDRA-8368:
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Summary: Consider not using hints for batchlog replay, in any
capacity
Key: CASSANDRA-8368
URL: https://issues.apache.org/jira/browse/CASSANDRA-8368
Project: Cassandra
Issue Type: Bug
Reporter: Aleksey Yeschenko
Fix For: 3.0
Currently, when replaying a batch, if a request times out, we simply write a
hint for it and call it a day.
It's simple, but it does tie us to hints, which some people prefer to disable
altogether (and some still will even after CASSANDRA-6230).
It also potentially violates the consistency level of the original request.
As an alternative, once CASSANDRA-7237 is complete, I suggest we stop relying
on hints at all, and do this instead:
1. Store the consistency level as batch metadata
2. On replay, hint in case of a timeout, but not if the node is down as per FD
3. If CL is met, consider the batch replayed and discard it, but not account
the hints towards CL (as per usual write patch), unless CL.ANY is being used
4. If CL is *not* met, write a new batch with contents of the current one, but
with timeuuid set in the future, for later replay (delayed by fixed
configurable time or exponentially backed off). With that new batch store the
list of nodes we've delivered the hint to, so that next time we replay it we
don't waste writes.
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