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https://issues.apache.org/jira/browse/CASSANDRA-10326?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14745656#comment-14745656
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Sylvain Lebresne commented on CASSANDRA-10326:
----------------------------------------------
bq. will you have time to look into this before GA?
I'll do my best. Starting by seeing if CASSANDRA-10344 makes a difference.
That said, it would help to get a more complete picture of what has been
benchmarked so far and the results. For instance, it seems those tests all use
reversed queries. I'm fine with reversed query, but does that mean forward
queries didn't exhibit the same differences? Or is it just that for some reason
you've started testing with reversed query and haven't results for forward
ones? Or is it the same results but you randomly picked those examples?
Basically, the more complete picture we have, the more likely we are to know
where we should start looking for inefficiencies.
> 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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