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https://issues.apache.org/jira/browse/HBASE-10263?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Feng Honghua updated HBASE-10263:
---------------------------------

    Release Note: 
4 new configurations are introduced:
hbase.lru.blockcache.single.percentage / hbase.lru.blockcache.multi.percentage 
/ hbase.lru.blockcache.memory.percentage / hbase.lru.rs.inmemoryforcemode
the first 3 enable user to config different single/multi/memory ratio in block 
cache; the last one determines if preemptive mode for memory block is enabled

> make LruBlockCache single/multi/in-memory ratio user-configurable and provide 
> preemptive mode for in-memory type block
> ----------------------------------------------------------------------------------------------------------------------
>
>                 Key: HBASE-10263
>                 URL: https://issues.apache.org/jira/browse/HBASE-10263
>             Project: HBase
>          Issue Type: Improvement
>          Components: io
>            Reporter: Feng Honghua
>            Assignee: Feng Honghua
>             Fix For: 0.99.0
>
>         Attachments: HBASE-10263-trunk_v0.patch, HBASE-10263-trunk_v1.patch, 
> HBASE-10263-trunk_v2.patch
>
>
> currently the single/multi/in-memory ratio in LruBlockCache is hardcoded 
> 1:2:1, which can lead to somewhat counter-intuition behavior for some user 
> scenario where in-memory table's read performance is much worse than ordinary 
> table when two tables' data size is almost equal and larger than 
> regionserver's cache size (we ever did some such experiment and verified that 
> in-memory table random read performance is two times worse than ordinary 
> table).
> this patch fixes above issue and provides:
> 1. make single/multi/in-memory ratio user-configurable
> 2. provide a configurable switch which can make in-memory block preemptive, 
> by preemptive means when this switch is on in-memory block can kick out any 
> ordinary block to make room until no ordinary block, when this switch is off 
> (by default) the behavior is the same as previous, using 
> single/multi/in-memory ratio to determine evicting.
> by default, above two changes are both off and the behavior keeps the same as 
> before applying this patch. it's client/user's choice to determine whether or 
> which behavior to use by enabling one of these two enhancements.



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