[
https://issues.apache.org/jira/browse/CASSANDRA-1902?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13016453#comment-13016453
]
T Jake Luciani commented on CASSANDRA-1902:
-------------------------------------------
Ok, reran on my box (4 core 4 gigs of ram). I also compared it to the
previously committed version of this patch (v3) I think v3 performs closer to
the way we want. it just needs to perserve the page list similar to the way v7
does and migrate them all at the end, just before the new sstables are swapped
in.
{noformat}
./bin/stress -n 100000 -c 10 -S 1024 -k
(ON) 226
(OFF) 229
(OLDON) 230
#flush
./bin/stress -n 100000 -o read
(ON) 34, 15
(OFF) 80, 15
(OLDON) 80, 15
./bin/stress -n 100000 -c 10 -S 1024 -k
(ON) 226
(OFF) 228
(OLDON) 226
./bin/stress -n 100000 -o read
(ON) 15
(OFF) 110, 15
(OLDON) 75, 15
#compact
#active reads
(ON) 110, 122, 153, 111, 66, 34, 96, 15
(OFF) 235, 134, 83, 60, 50, 90, 80, 20
(OLDON) 21, 15, 15, 15, 15, 15,…, 119, 40, 15
{noformat}
> Migrate cached pages during compaction
> ---------------------------------------
>
> Key: CASSANDRA-1902
> URL: https://issues.apache.org/jira/browse/CASSANDRA-1902
> Project: Cassandra
> Issue Type: Improvement
> Components: Core
> Affects Versions: 0.7.1
> Reporter: T Jake Luciani
> Assignee: Pavel Yaskevich
> Fix For: 0.7.5, 0.8
>
> Attachments:
> 0001-CASSANDRA-1902-cache-migration-impl-with-config-option.txt,
> 1902-BufferedSegmentedFile-logandsleep.txt, 1902-formatted.txt,
> 1902-per-column-migration-rebase2.txt, 1902-per-column-migration.txt,
> CASSANDRA-1902-v3.patch, CASSANDRA-1902-v4.patch, CASSANDRA-1902-v5.patch,
> CASSANDRA-1902-v6.patch, CASSANDRA-1902-v7.patch
>
> Original Estimate: 32h
> Time Spent: 56h
> Remaining Estimate: 0h
>
> Post CASSANDRA-1470 there is an opportunity to migrate cached pages from a
> pre-compacted CF during the compaction process. This is now important since
> CASSANDRA-1470 caches effectively nothing.
> For example an active CF being compacted hurts reads since nothing is cached
> in the new SSTable.
> The purpose of this ticket then is to make sure SOME data is cached from
> active CFs. This can be done my monitoring which Old SSTables are in the page
> cache and caching active rows in the New SStable.
> A simpler yet similar approach is described here:
> http://insights.oetiker.ch/linux/fadvise/
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
