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https://issues.apache.org/jira/browse/HBASE-16205?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15389634#comment-15389634
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Anoop Sam John commented on HBASE-16205:
----------------------------------------
upsert() is calling
cell = deepCopyIfNeeded(cell);
You mean why it is not tried to copy to MSLAB? The reason is written over
there. This is this way from long time.
{code}
// Add the Cell to the MemStore
// Use the internalAdd method here since we (a) already have a lock
// and (b) cannot safely use the MSLAB here without potentially
// hitting OOME - see TestMemStore.testUpsertMSLAB for a
// test that triggers the pathological case if we don't avoid MSLAB
// here.
long addedSize = internalAdd(cell, false);
{code}
> When Cells are not copied to MSLAB, deep clone it while adding to Memstore
> --------------------------------------------------------------------------
>
> Key: HBASE-16205
> URL: https://issues.apache.org/jira/browse/HBASE-16205
> Project: HBase
> Issue Type: Sub-task
> Components: regionserver
> Affects Versions: 2.0.0
> Reporter: Anoop Sam John
> Assignee: Anoop Sam John
> Priority: Critical
> Fix For: 2.0.0
>
> Attachments: HBASE-16205.patch, HBASE-16205_V2.patch,
> HBASE-16205_V3.patch, HBASE-16205_V3.patch
>
>
> This is imp after HBASE-15180 optimization. After that we the cells flowing
> in write path will be backed by the same byte[] where the RPC read the
> request into. By default we have MSLAB On and so we have a copy operation
> while adding Cells to memstore. This copy might not be there if
> 1. MSLAB is turned OFF
> 2. Cell size is more than a configurable max size. This defaults to 256 KB
> 3. If the operation is Append/Increment.
> In such cases, we should just clone the Cell into a new byte[] and then add
> to memstore. Or else we keep referring to the bigger byte[] chunk for longer
> time.
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