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https://issues.apache.org/jira/browse/CASSANDRA-14771?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16622772#comment-16622772
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Benedict edited comment on CASSANDRA-14771 at 4/1/19 2:18 PM:
--------------------------------------------------------------
Just for clarity of future readers, per CASSANDRA-14768, we might still want to
*write* to transient nodes if we would fail to reach QUORUM in any DC; this
will only be necessary in configurations where full replicas do not constitute
a QUORUM. These transient writes might themselves be protected by further
transient writes if any fail, though writes to full replicas will not be
protected in this way.
(edited, to fix nonsensical content)
was (Author: benedict):
Just for clarity of future readers, per CASSANDRA-14768, we might still want to
*write* to transient nodes if, due to timeouts on writes to full nodes, we fail
to reach {{QUORUM}} in any given DC. But we wouldn't pick any upfront since
we'd fail with unavailable if we can't find enough full to write to, would not
*rapid write protection* to them, and would not block our response on them.
Probably this can fairly easily be implemented by narrowing the candidates set
to only the full replicas to prevent speculation, and using a simple
{{AbstractWriteResponseHandler}} with {{blockFor}} set to the full node count.
Note, this is an aside for understanding some of the complexities here. This
won't be addressed in this ticket, but in CASSANDRA-14768 (or a related
followup).
> Transient Replication: Writes at CL.ALL should block on all full replicas,
> but not transients
> ----------------------------------------------------------------------------------------------
>
> Key: CASSANDRA-14771
> URL: https://issues.apache.org/jira/browse/CASSANDRA-14771
> Project: Cassandra
> Issue Type: Bug
> Components: Feature/Transient Replication
> Reporter: Ariel Weisberg
> Priority: Normal
> Fix For: 4.0
>
>
> Reading at ONE will still be safe because ONE only selects full replicas.
> There is no reason to write to transients if we are going to block on all
> full replicas.
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