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From "stack (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HBASE-14940) Make our unsafe based ops more safe
Date Fri, 18 Dec 2015 17:17:46 GMT

    [ https://issues.apache.org/jira/browse/HBASE-14940?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15064246#comment-15064246
] 

stack commented on HBASE-14940:
-------------------------------

Is this shortened format your doing [~busbey] ? If not, I'll dig in.

Let me rerun patch...

> 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, HBASE-14940_branch-1.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.



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