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https://issues.apache.org/jira/browse/CASSANDRA-16036?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17180856#comment-17180856
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Jon Meredith commented on CASSANDRA-16036:
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Thanks for doing the extra benchmarking. Results seem to be fairly close, and
to get the best out of things users would need to optimize and benchmark anyway
to work out how to use their memory budget.
+1 from me, with a minor nit that it would be good to update
{{conf/cassandra.yaml}} with a commented out entry and some description of what
the setting controls.
> Add flag to disable chunk cache and disable by default
> ------------------------------------------------------
>
> Key: CASSANDRA-16036
> URL: https://issues.apache.org/jira/browse/CASSANDRA-16036
> Project: Cassandra
> Issue Type: Bug
> Components: Legacy/Local Write-Read Paths
> Reporter: David Capwell
> Assignee: David Capwell
> Priority: Normal
> Fix For: 4.0-beta
>
> Attachments: async-profile.collapsed.svg,
> clustering-in-clause_latency_selects_baseline.png,
> clustering-in-clause_latency_selects_baseline_attempt3.png,
> clustering-in-clause_latency_under90_selects_baseline.png,
> clustering-in-clause_latency_under90_selects_baseline_attempt3.png,
> clustering-slice_latency_selects_baseline.png,
> clustering-slice_latency_under90_selects_baseline.png,
> medium-blobs_latency_selects_baseline.png,
> medium-blobs_latency_under90_selects_baseline.png,
> partition-single-row-read_latency_selects_baseline.png,
> partition-single-row-read_latency_under90_selects_baseline.png
>
>
> Chunk cache is enabled by default and doesn’t have a flag to disable without
> impacting networking. In performance testing 4.0 against 3.0 I found that
> reads were slower in 4.0 and after profiling found that the ChunkCache was
> partially to blame; after disabling the chunk cache, read performance had
> improved.
> {code}
> 40_w_cc-selects.hdr
> #[Mean = 11.50063, StdDeviation = 13.44014]
> #[Max = 482.41254, Total count = 316477]
> #[Buckets = 25, SubBuckets = 262144]
> 40_wo_cc-selects.hdr
> #[Mean = 9.82115, StdDeviation = 10.14270]
> #[Max = 522.36493, Total count = 317444]
> #[Buckets = 25, SubBuckets = 262144]
> {code}
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