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https://issues.apache.org/jira/browse/CASSANDRA-10326?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14804638#comment-14804638
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Benedict commented on CASSANDRA-10326:
--------------------------------------
[One
more|http://cstar.datastax.com/graph?stats=6dbe3ee4-5d7b-11e5-a4e4-42010af0688f&metric=op_rate&operation=1_user&smoothing=1&show_aggregates=true&xmin=0&xmax=869.99&ymin=0&ymax=145546.5]
([and
again|http://cstar.datastax.com/tests/id/1ea46496-5d53-11e5-a4e4-42010af0688f).
This is with compression disabled and again not reversed. Performance is much
closer, but random point queries are still significantly slower.
CASSANDRA-10322 makes up a significant chunk of that, but is still 25% slower.
Notably, 2.2 produces less garbage and more consistent results (the two
possibly related).
It's also worth noting these datasets are still in-memory, so it's still quite
likely users with larger than memory datasets will see an improvement (not that
we shouldn't strive to fix this). We should probably run some other tests on
that front, although obviously that takes a lot longer.
> Performance is worse in 3.0
> ---------------------------
>
> Key: CASSANDRA-10326
> URL: https://issues.apache.org/jira/browse/CASSANDRA-10326
> Project: Cassandra
> Issue Type: Bug
> Reporter: Benedict
> Priority: Critical
> Fix For: 3.0.x
>
>
> Performance is generally turning out to be worse after 8099, despite a number
> of unrelated performance enhancements being delivered. This isn't entirely
> unexpected, given a great deal of time was spent optimising the old code,
> however things appear worse than we had hoped.
> My expectation was that workloads making extensive use of CQL constructs
> would be faster post-8099, however the latest tests performed with very large
> CQL rows, including use of collections, still exhibit performance below that
> of 2.1 and 2.2.
> Eventually, as the dataset size grows large enough and the locality of access
> is just right, the reduction in size of our dataset will yield a window
> during which some users will perform better due simply to improved page cache
> hit rates. We seem to see this in some of the tests. However we should be at
> least as fast (and really faster) off the bat.
> The following are some large partition benchmark results, with as many as 40K
> rows per partition, running LCS. There are a number of parameters we can
> modify to see how behaviour changes and under what scenarios we might still
> be faster, but the picture painted isn't brilliant, and is consistent, so we
> should really try and figure out what's up before GA.
> [trades-with-flags (collections),
> blade11b|http://cstar.datastax.com/graph?stats=f0a17292-5a13-11e5-847a-42010af0688f&metric=op_rate&operation=1_user&smoothing=1&show_aggregates=true&xmin=0&xmax=4387.02&ymin=0&ymax=122951.4]
> [trades-with-flags (collections),
> blade11|http://cstar.datastax.com/graph?stats=e25aaaa0-5a13-11e5-ae0d-42010af0688f&metric=op_rate&operation=1_user&smoothing=1&show_aggregates=true&xmin=0&xmax=4424.75&ymin=0&ymax=130158.6]
> [trades (no collections),
> blade11|http://cstar.datastax.com/graph?stats=9b7da48e-570c-11e5-90fe-42010af0688f&metric=op_rate&operation=1_user&smoothing=1&show_aggregates=true&xmin=0&xmax=2682.46&ymin=0&ymax=142547.9]
> [~slebresne]: will you have time to look into this before GA?
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