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https://issues.apache.org/jira/browse/HBASE-15786?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15653032#comment-15653032
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stack commented on HBASE-15786:
-------------------------------
Is the subject correct? Maybe say more what the patch is doing. I did a first
pass.
When do I need this piecemeal copying? copyRowTo ... copying from a Cell to a
ByteBuffer? Can I not use the original Cell instead of the new ByteBuffer?
We've talked about this before, we don't want the Cell doing its own
serialization? In appendKeyTo over in KVUtil, there is an external dependency
on a particular structure. It makes it hard ever changing the Cell layout when
it is in more than just one place.
We have appendKeyTo which appends to a ByteBuffer? And then appendToByteBuffer
which appends to a ByteBuffer. Why we have to say ByteBuffer in latter case but
not in the first? Later we have copyCellTo...
Sometimes we are saying ByteBuffered as in ByteBufferedCell and now we are
starting to say ByteBuffer instead as in ByteBufferWriter or ByteBufferUtil
MemorySizeUtil needs class comment explaining it. Don't you have a nice write
up on how this thing operators that you could copy/paste in here?
We need to work on moving mslab and chunk etc. out to a memory module? Move
things like MemStoreLABImpl out of regionserver package?
Shouldn't we scream when mslab is not on now?
1468 if (conf.getBoolean(MemStoreLAB.USEMSLAB_KEY,
MemStoreLAB.USEMSLAB_DEFAULT)) {
It means you are missing out on a bunch of stuff?
Should the DefaultHeapMemoryTuner be renamed now you've renamed the class as
MemorySizeUtil?
Say more on what this patch is doing?
AN HRegion needs reference to RegionServerServices memory management?
> Create Offheap Memstore
> -----------------------
>
> Key: HBASE-15786
> URL: https://issues.apache.org/jira/browse/HBASE-15786
> Project: HBase
> Issue Type: Sub-task
> Components: regionserver
> Reporter: ramkrishna.s.vasudevan
> Assignee: Anoop Sam John
> Fix For: 2.0.0
>
> Attachments: HBASE-15786.patch
>
>
> We can make use of MSLAB pool for this off heap memstore.
> Right now one can specify the global memstore size (heap size) as a % of max
> memory using a config. We will add another config with which one can specify
> the global off heap memstore size. This will be exact size not as %. When off
> heap memstore in use, we will give this entire area for the MSLAB pool and
> that will create off heap chunks. So when cells are added to memstore, the
> cell data gets copied into the off heap MSLAB chunk spaces. Note that when
> the pool size is not really enough and we need additional chunk creation, we
> wont use off heap area for that. We dony want to create so many on demand
> DBBs.
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