[
https://issues.apache.org/jira/browse/HBASE-16205?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15376469#comment-15376469
]
Anoop Sam John commented on HBASE-16205:
----------------------------------------
Sorry am not getting what you actually trying to ask here. You say we dont
need to copy to MSLAB and/or deep copy.
Yes when the RCP read the req it will create enough sized bytes such that both
cells data is in the same bigger sized byte[]. After HBASE-15180, when the
Codec decoder create Cells out of the byte[], it will just create cell wrap
over this same byte[]. No copy of the specific cell bytes at this time. Later
when a cell is abt to add to MSLAB, it's bytes copied to MSLAB chunk. A chunk
will have default size of 2 MB. We have MSLAB chunk pooling also. These are
efforts to avoid fragmentation.
> 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
>
>
> 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.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
