[jira] [Comment Edited] (HBASE-15180) Reduce garbage created while reading Cells from Codec Decoder

["Esteban Gutierrez (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-15180?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15126709#comment-15126709 ] 

Esteban Gutierrez edited comment on HBASE-15180 at 2/1/16 6:22 PM:
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Good stuff [~jingcheng.du@intel.com]. Very interesting numbers, I expected further tuning to provide a better throughput too, but didn't tried with larger chucks (my test was around 24GB). Once I have a chance, I'm going to re-run my tests with JDK8 u80 and I let you know to let you know if I'm seeing the same behavior.


was (Author: esteban):
Good stuff [~jingcheng.du@intel.com]. Very interesting numbers, I expected further tuning to provide a throughput, but didn't tried with larger chucks (my test was around 24GB). Once I have a chance, I'm going to re-run my tests with JDK8 u80 and I let you know to let you know if I'm seeing the same behavior.

> Reduce garbage created while reading Cells from Codec Decoder
> -------------------------------------------------------------
>
>                 Key: HBASE-15180
>                 URL: https://issues.apache.org/jira/browse/HBASE-15180
>             Project: HBase
>          Issue Type: Sub-task
>          Components: regionserver
>            Reporter: Anoop Sam John
>            Assignee: Anoop Sam John
>             Fix For: 2.0.0
>
>         Attachments: HBASE-15180.patch, HBASE-15180_V2.patch
>
>
> In KeyValueDecoder#parseCell (Default Codec decoder) we use KeyValueUtil#iscreate to read cells from the InputStream. Here we 1st create a byte[] of length 4 and read the cell length and then an array of Cell's length and read in cell bytes into it and create a KV.
> Actually in server we read the reqs into a byte[] and CellScanner is created on top of a ByteArrayInputStream on top of this. By default in write path, we have MSLAB usage ON. So while adding Cells to memstore, we will copy the Cell bytes to MSLAB memory chunks (default 2 MB size) and recreate Cells over that bytes.  So there is no issue if we create Cells over the RPC read byte[] directly here in Decoder.  No need for 2 byte[] creation and copy for every Cell in request.
> My plan is to make a Cell aware ByteArrayInputStream which can read Cells directly from it.  
> Same Codec path is used in client side also. There better we can avoid this direct Cell create and continue to do the copy to smaller byte[]s path.  Plan to introduce some thing like a CodecContext associated with every Codec instance which can say the server/client context.



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