Benedict created CASSANDRA-10326:
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Summary: 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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