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https://issues.apache.org/jira/browse/CASSANDRA-1902?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Pavel Yaskevich updated CASSANDRA-1902:
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    Assignee: Pavel Yaskevich  (was: T Jake Luciani)

> 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
>
>   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/

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