[
https://issues.apache.org/jira/browse/HBASE-14940?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15050224#comment-15050224
]
ramkrishna.s.vasudevan commented on HBASE-14940:
------------------------------------------------
Regarding the COPY_THRESHOLD thing that VM does, I could see many other
projects that deal with Unsafe also omits that check. Including the alignment
but handles the Endian part. Just saying this for info. So may be other code
bases can also see how this can be done. But from me I feel this is ok as the
alignment is handled here and if there is no alignment then we fall back to the
normal way right?
> Make our unsafe based ops more safe
> -----------------------------------
>
> Key: HBASE-14940
> URL: https://issues.apache.org/jira/browse/HBASE-14940
> Project: HBase
> Issue Type: Bug
> Reporter: Anoop Sam John
> Assignee: Anoop Sam John
> Attachments: HBASE-14940.patch
>
>
> Thanks for the nice findings [~ikeda]
> This jira solves 3 issues with Unsafe operations and ByteBufferUtils
> 1. We can do sun unsafe based reads and writes iff unsafe package is
> available and underlying platform is having unaligned-access capability. But
> we were missing the second check
> 2. Java NIO is doing a chunk based copy while doing Unsafe copyMemory. The
> max chunk size is 1 MB. This is done for "A limit is imposed to allow for
> safepoint polling during a large copy" as mentioned in comments in Bits.java.
> We are also going to do same way
> 3. In ByteBufferUtils, when Unsafe is not available and ByteBuffers are off
> heap, we were doing byte by byte operation (read/copy). We can avoid this and
> do better way.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
