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https://issues.apache.org/jira/browse/CASSANDRA-7486?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Benedict reopened CASSANDRA-7486:
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We should revert this patch until we can do further analysis. We have
significantly worse throughput and latency figures in 3.0, and much of this can
be explained by the new GC settings. This is with more realistic workloads than
we have previously benchmarked, and also with the current state of 3.0.
[These
graphs|http://cstar.datastax.com/graph?stats=518e5484-5ee3-11e5-b421-42010af0688f&metric=op_rate&operation=3_user&smoothing=1&show_aggregates=true&xmin=0&xmax=113.3&ymin=0&ymax=159847.6]
paint a bleak picture. Throughput takes a 33% hit for point queries
(Interestingly, there is a reduction in GC _work_ done, presumably indicating
that card marking / GC store barriers are to blame). Latency is much worse, and
much less consistent, as is throughput, for all runs.
We may be able to use this information to counteract the problem, but releasing
3.0 GA with this change as stands seems premature.
> Migrate to G1GC by default
> --------------------------
>
> Key: CASSANDRA-7486
> URL: https://issues.apache.org/jira/browse/CASSANDRA-7486
> Project: Cassandra
> Issue Type: New Feature
> Components: Config
> Reporter: Jonathan Ellis
> Assignee: Albert P Tobey
> Fix For: 3.0 alpha 1
>
>
> See
> http://www.slideshare.net/MonicaBeckwith/garbage-first-garbage-collector-g1-7486gc-migration-to-expectations-and-advanced-tuning
> and https://twitter.com/rbranson/status/482113561431265281
> May want to default 2.1 to G1.
> 2.1 is a different animal from 2.0 after moving most of memtables off heap.
> Suspect this will help G1 even more than CMS. (NB this is off by default but
> needs to be part of the test.)
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