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https://issues.apache.org/jira/browse/HBASE-7381?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13534710#comment-13534710
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Lars Hofhansl commented on HBASE-7381:
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Result in trunk already has a copyFrom method. I added that while removing
Writable from Result.
Let's call it the same in 0.94.
Note that this is only needed to mapred (and API requiring mutable objects is
an abomination - IMHO).
I'm fine making this change in 0.94, should then also fix TableRecordReaderImpl
by calling this API.
> Lightweight data transfer for Class Result
> ------------------------------------------
>
> Key: HBASE-7381
> URL: https://issues.apache.org/jira/browse/HBASE-7381
> Project: HBase
> Issue Type: Improvement
> Components: Client
> Reporter: Cheng Hao
> Priority: Trivial
> Fix For: 0.94.4
>
> Attachments: result_lightweight_copy.patch
>
>
> Currently,the data transferring between 2 Result objects in the same process,
> will cause additional/unnecessary data parsing & copying; as we have to do
> that via "Writables.copyWritable(result1, result2)", which internally is
> serialization, data copying, and de-serialization.
> The use case are quite common when integrated with Hadoop job running;
> The protocol org.apache.hadoop.mapred.RecordReader defined in Hadoop,
> provides 3 interfaces:
> 1) K createKey();
> 2) V createValue();
> 3) boolean next(K key, V value) throws IOException;
> In the 3rd method implementation, most likely requires the value (should be
> Result object) to be filled, with the Result object from HBase.
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