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https://issues.apache.org/jira/browse/HBASE-4027?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jean-Daniel Cryans updated HBASE-4027:
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Release Note: Setting -XX:MaxDirectMemorySize in hbase-env.sh enables this
feature. The file already has a line you can uncomment and you need to set the
size of the direct memory (your total memory - size allocated to memstores -
size allocated to the normal block cache - some head room for the other
functionalities). (was: Allows the enabling off an off heap cache in hbase.
Set hbase.offheapcachesize in hbase-site.xml
Then, uncomment the line in hbase-env.sh. Cache does a slab allocation model
similar to memcached.
)
I changed the release note, the patch doesn't have a "hbase.offheapcachesize"
configuration and it's enabled as soon as you set -XX:MaxDirectMemorySize
(which is actually a big problem when you consider this:
http://hbase.apache.org/book.html#trouble.client.oome.directmemory.leak). I'm
opening followup jiras.
> Enable direct byte buffers LruBlockCache
> ----------------------------------------
>
> Key: HBASE-4027
> URL: https://issues.apache.org/jira/browse/HBASE-4027
> Project: HBase
> Issue Type: Improvement
> Reporter: Jason Rutherglen
> Assignee: Li Pi
> Priority: Minor
> Fix For: 0.92.0
>
> Attachments: 4027-v5.diff, 4027v7.diff, HBase-4027 (1).pdf,
> HBase-4027.pdf, HBase4027v8.diff, HBase4027v9.diff, hbase-4027-v10.5.diff,
> hbase-4027-v10.diff, hbase-4027v10.6.diff, hbase-4027v13.1.diff,
> hbase-4027v15.3.diff, hbase-4027v6.diff, hbase4027v11.5.diff,
> hbase4027v11.6.diff, hbase4027v11.7.diff, hbase4027v11.diff,
> hbase4027v12.1.diff, hbase4027v12.diff, hbase4027v15.2.diff,
> slabcachepatch.diff, slabcachepatchv2.diff, slabcachepatchv3.1.diff,
> slabcachepatchv3.2.diff, slabcachepatchv3.diff, slabcachepatchv4.5.diff,
> slabcachepatchv4.diff
>
>
> Java offers the creation of direct byte buffers which are allocated outside
> of the heap.
> They need to be manually free'd, which can be accomplished using an
> documented {{clean}} method.
> The feature will be optional. After implementing, we can benchmark for
> differences in speed and garbage collection observances.
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