[
https://issues.apache.org/jira/browse/CASSANDRA-8523?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15228474#comment-15228474
]
Joel Knighton commented on CASSANDRA-8523:
------------------------------------------
I don't have a good idea for a low-hanging solution here - I think the cleanest
is the combination of a new gossip state for replacing nodes + enhancement of
the failure detector/token metadata. Since that's a bigger change, let's also
make sure that it doesn't conflict with plans for strongly consistent
membership. I'd really rather not couple gossip status to the internals of the
read/write paths.
I also agree that we should make sure that we kill two birds with one stone and
handle this and [CASSANDRA-9244] at the same time.
Let me know if I can help in design and/or review.
> 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: Brandon Williams
> 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.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
