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https://issues.apache.org/jira/browse/CASSANDRA-4718?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14000739#comment-14000739
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Pavel Yaskevich commented on CASSANDRA-4718:
--------------------------------------------
[~benedict] Isn't CQL trying to be smart about request routing like Thrift?
Anyhow, read concurrency was default 128 (can you confirm [~jasobrown]?) and we
do remove all of the files, drop cache, restart, disable compaction to remove
jitter as much as possible, so the only difference between two runs is one has
sep patch another doesn't, if there are slow reads that should be happening in
both runs because keys are read uniformly and although there is a big amount of
sstables in the system for every read there is only one hit, which pretty much
simulates the behavior of the systems where data accumulates over time. Also I
can tell you that setup that we have for I/O is able to handle mere 300GB
without a problem.
> More-efficient ExecutorService for improved throughput
> ------------------------------------------------------
>
> Key: CASSANDRA-4718
> URL: https://issues.apache.org/jira/browse/CASSANDRA-4718
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Jonathan Ellis
> Assignee: Benedict
> Priority: Minor
> Labels: performance
> Fix For: 2.1.0
>
> Attachments: 4718-v1.patch, PerThreadQueue.java,
> austin_diskbound_read.svg, aws.svg, aws_read.svg,
> backpressure-stress.out.txt, baq vs trunk.png,
> belliotsmith_branches-stress.out.txt, jason_read.svg, jason_read_latency.svg,
> jason_write.svg, op costs of various queues.ods, stress op rate with various
> queues.ods, stress_2014May15.txt, stress_2014May16.txt, v1-stress.out
>
>
> Currently all our execution stages dequeue tasks one at a time. This can
> result in contention between producers and consumers (although we do our best
> to minimize this by using LinkedBlockingQueue).
> One approach to mitigating this would be to make consumer threads do more
> work in "bulk" instead of just one task per dequeue. (Producer threads tend
> to be single-task oriented by nature, so I don't see an equivalent
> opportunity there.)
> BlockingQueue has a drainTo(collection, int) method that would be perfect for
> this. However, no ExecutorService in the jdk supports using drainTo, nor
> could I google one.
> What I would like to do here is create just such a beast and wire it into (at
> least) the write and read stages. (Other possible candidates for such an
> optimization, such as the CommitLog and OutboundTCPConnection, are not
> ExecutorService-based and will need to be one-offs.)
> AbstractExecutorService may be useful. The implementations of
> ICommitLogExecutorService may also be useful. (Despite the name these are not
> actual ExecutorServices, although they share the most important properties of
> one.)
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