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https://issues.apache.org/jira/browse/CASSANDRA-8523?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15340771#comment-15340771
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Paulo Motta commented on CASSANDRA-8523:
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bq. The hints that you might care about are writes dropped during the
replacement on the replacing node.
Even these should not be a problem, because they are also forwarded to the
replacement node, and if they fail they are hinted to replacement node ID.
I rebased and resubmitted dtests and fixed minor typo on the original patch. I
also realized it's not necessary to change original node state to
{{REMOVED_TOKEN}} because it's already removed from gossip when the replacement
node changes its state to {{NORMAL}}, so I removed that step.
Also added new dtests to test replace in a mixed-version environment to verify
backward compatibility and to check for the warning message when replacing a
node with the same address.
> Writes should be sent to a replacement node while it is streaming in data
> -------------------------------------------------------------------------
>
> Key: CASSANDRA-8523
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8523
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Richard Wagner
> Assignee: Paulo Motta
> Fix For: 2.1.x
>
>
> In our operations, we make heavy use of replace_address (or
> replace_address_first_boot) in order to replace broken nodes. We now realize
> that writes are not sent to the replacement nodes while they are in hibernate
> state and streaming in data. This runs counter to what our expectations were,
> especially since we know that writes ARE sent to nodes when they are
> bootstrapped into the ring.
> It seems like cassandra should arrange to send writes to a node that is in
> the process of replacing another node, just like it does for a nodes that are
> bootstraping. I hesitate to phrase this as "we should send writes to a node
> in hibernate" because the concept of hibernate may be useful in other
> contexts, as per CASSANDRA-8336. Maybe a new state is needed here?
> Among other things, the fact that we don't get writes during this period
> makes subsequent repairs more expensive, proportional to the number of writes
> that we miss (and depending on the amount of data that needs to be streamed
> during replacement and the time it may take to rebuild secondary indexes, we
> could miss many many hours worth of writes). It also leaves us more exposed
> to consistency violations.
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