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https://issues.apache.org/jira/browse/CASSANDRA-11320?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Stefania updated CASSANDRA-11320:
---------------------------------
Tester: (was: Ariel Weisberg)
Status: Patch Available (was: Awaiting Feedback)
> Improve backoff policy for cqlsh COPY FROM
> ------------------------------------------
>
> Key: CASSANDRA-11320
> URL: https://issues.apache.org/jira/browse/CASSANDRA-11320
> Project: Cassandra
> Issue Type: Improvement
> Components: Tools
> Reporter: Stefania
> Assignee: Stefania
> Labels: doc-impacting
> Fix For: 3.x
>
>
> Currently we have an exponential back-off policy in COPY FROM that kicks in
> when timeouts are received. However there are two limitations:
> * it does not cover new requests and therefore we may not back-off
> sufficiently to give time to an overloaded server to recover
> * the pause is performed in the receiving thread and therefore we may not
> process server messages quickly enough
> There is a static throttling mechanism in rows per second from feeder to
> worker processes (the INGESTRATE) but the feeder has no idea of the load of
> each worker process. However it's easy to keep track of how many chunks a
> worker process has yet to read by introducing a bounded semaphore.
> The idea is to move the back-off pauses to the worker processes main thread
> so as to include all messages, new and retries, not just the retries that
> timed out. The worker process will not read new chunks during the back-off
> pauses, and the feeder process can then look at the number of pending chunks
> before sending new chunks to a worker process.
> [~aholmber], [~aweisberg] what do you think?
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