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https://issues.apache.org/jira/browse/PIG-201?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12587558#action_12587558
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Mathieu Poumeyrol commented on PIG-201:
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Ho ! The 8Kb buffer size is just plain guess. I honestly have no idea about the
"right" value.
> BufferedPositionedInputStream is not buffered
> ---------------------------------------------
>
> Key: PIG-201
> URL: https://issues.apache.org/jira/browse/PIG-201
> Project: Pig
> Issue Type: Bug
> Reporter: Mathieu Poumeyrol
> Attachments: BufferedPositionedInputStream.patch
>
>
> BufferedPositionedInputStream is actualy not buffered, leading (I guess) to
> constant round trip to dfs as byte are read one by one. I just wrapped the
> provided input stream in the constructor in a good old BufferedInputStream.
> I measured a 40% performance boost on a script that reads and writes 3.7GB in
> dfs through PigStorage on one node. I guess the impact may be greater on a
> real hdfs cluster with actual network roundtrips.
> FYI, the issue was found while profiling with Yourkit java profiler. Usefull
> toy...
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