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https://issues.apache.org/jira/browse/HBASE-21874?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16769596#comment-16769596
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Anoop Sam John commented on HBASE-21874:
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bq.If you keep data in PMEM and use extended FileMmapIOEngine, where do yo you
mmap it into? into DRAM? That is strange
bq. You mmap PMEM resided file into RAM
No.. The mmap call will NOT bring data into DRAM. The Pmem device is direct
accessible for CPU with load/store instructions. The mmap will just give a
ByteBuffer with the address in Pmem.
> Bucket cache on Persistent memory
> ---------------------------------
>
> Key: HBASE-21874
> URL: https://issues.apache.org/jira/browse/HBASE-21874
> Project: HBase
> Issue Type: New Feature
> Components: BucketCache
> Affects Versions: 3.0.0
> Reporter: ramkrishna.s.vasudevan
> Assignee: ramkrishna.s.vasudevan
> Priority: Major
> Fix For: 3.0.0
>
> Attachments: HBASE-21874.patch, HBASE-21874.patch,
> HBASE-21874_V2.patch, Pmem_BC.png
>
>
> Non volatile persistent memory devices are byte addressable like DRAM (for
> eg. Intel DCPMM). Bucket cache implementation can take advantage of this new
> memory type and can make use of the existing offheap data structures to serve
> data directly from this memory area without having to bring the data to
> onheap.
> The patch is a new IOEngine implementation that works with the persistent
> memory.
> Note : Here we don't make use of the persistence nature of the device and
> just make use of the big memory it provides.
> Performance numbers to follow.
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