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https://issues.apache.org/jira/browse/HBASE-20045?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16388663#comment-16388663
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Jean-Marc Spaggiari commented on HBASE-20045:
---------------------------------------------

Thanks for sharing [~vrodionov]. Sad to hear for Cassandra OnHeap memory 
impact. Wondering how this applies to HBase OffHeap memory cache. I guess at 
some point we will figure it out.

[~anoop.hbase] I highly doubt I will have any time soon to work on that :(

> When running compaction, cache recent blocks.
> ---------------------------------------------
>
>                 Key: HBASE-20045
>                 URL: https://issues.apache.org/jira/browse/HBASE-20045
>             Project: HBase
>          Issue Type: New Feature
>          Components: BlockCache, Compaction
>    Affects Versions: 2.0.0-beta-1
>            Reporter: Jean-Marc Spaggiari
>            Priority: Major
>
> HBase already allows to cache blocks on flush. This is very useful for 
> usecases where most queries are against recent data. However, as soon as 
> their is a compaction, those blocks are evicted. It will be interesting to 
> have a table level parameter to say "When compacting, cache blocks less than 
> 24 hours old". That way, when running compaction, all blocks where some data 
> are less than 24h hold, will be automatically cached. 
>  
> Very useful for table design where there is TS in the key but a long history 
> (Like a year of sensor data).



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