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From "Benjamin Reed (JIRA)" <j...@apache.org>
Subject [jira] Commented: (PIG-599) BufferedPositionedInputStream isn't buffered
Date Fri, 09 Jan 2009 13:15:59 GMT

    [ https://issues.apache.org/jira/browse/PIG-599?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12662359#action_12662359
] 

Benjamin Reed commented on PIG-599:
-----------------------------------

+1 looks good.

> BufferedPositionedInputStream isn't buffered
> --------------------------------------------
>
>                 Key: PIG-599
>                 URL: https://issues.apache.org/jira/browse/PIG-599
>             Project: Pig
>          Issue Type: Bug
>          Components: impl
>    Affects Versions: types_branch
>            Reporter: Alan Gates
>            Assignee: Alan Gates
>             Fix For: types_branch
>
>         Attachments: loadperf-2.patch, loadperf.patch
>
>
> org.apache.pig.impl.io.BufferedPositionedInputStream is not actually buffered.  This
is because it sits atop a FSDataInputStream (somewhere down the stack), which is buffered.
 So to avoid double buffering, which can be bad, BufferedPositionedInputStream was written
without buffering.  But the FSDataInputStream is far enough down the stack that it is still
quite costly to call read() individually for each byte.  A run through a profiler shows that
a fair amount of time is being spent in BufferedPositionedInputStream.read().

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