ramkrishna.s.vasudevan created HBASE-17233:

             Summary: See if we should replace System.arrayCopy with 
                 Key: HBASE-17233
                 URL: https://issues.apache.org/jira/browse/HBASE-17233
             Project: HBase
          Issue Type: Improvement
    Affects Versions: 2.0.0
            Reporter: ramkrishna.s.vasudevan
            Assignee: ramkrishna.s.vasudevan

Just saw this interesting comment in PB code. Since we deal with byte[] 
extensively (when we are onheap) we do lot of copies too.
* <p>One of the noticeable costs of copying a byte[] into a new array using
   * {@code System.arraycopy} is nullification of a new buffer before the copy. 
It has been shown
   * the Hotspot VM is capable to intrisicfy {@code Arrays.copyOfRange} 
operation to avoid this
   * expensive nullification and provide substantial performance gain. 
Unfortunately this does not
   * hold on Android runtimes and could make the copy slightly slower due to 
additional code in
   * the {@code Arrays.copyOfRange}. 
So since we are hotspot VM we could see if the places we use System.arrayCopy 
can be replaced with Arrays.copyOfRange.

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