[
https://issues.apache.org/jira/browse/CASSANDRA-8897?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14557670#comment-14557670
]
Benedict commented on CASSANDRA-8897:
-------------------------------------
It would be nice to run some tests that show this change's strengths: if you
disable auto-compaction on cstar (not sure if you can do this), and make the
memtable size very small, then we can produce a workload with many sstables
that still fit in memory. If we aim to write say 4G of data, but perhaps with
many overwrites so each operation has to touch multiple files (so perhaps only
400M of data written 10 times, or 4G of data with 10+ clustering values,
written with visits=fixed(10)). If we set the memtable size to <= 100Mb, this
will likely result in files of <= 30Mb, giving us 120+ sstables. If we
constrain the size of the file cache to just 64Mb, say, we should on a random
read workload see much more GC activity under the old scheme, and likely
reduced throughput.
> Remove FileCacheService, instead pooling the buffers
> ----------------------------------------------------
>
> Key: CASSANDRA-8897
> URL: https://issues.apache.org/jira/browse/CASSANDRA-8897
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Reporter: Benedict
> Assignee: Stefania
> Fix For: 3.x
>
> Attachments: 9240_test_results.txt,
> snapshot-1431582436640-cpu-backtraces.png,
> snapshot-1431582436640-cpu-calltree-compression-8897.nps,
> snapshot-1431582436640-cpu-calltree-compression-trunk.nps
>
>
> After CASSANDRA-8893, a RAR will be a very lightweight object and will not
> need caching, so we can eliminate this cache entirely. Instead we should have
> a pool of buffers that are page-aligned.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
