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From "Uli Bubenheimer (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (IO-355) IOUtils copyLarge() and skip() methods are performance hogs
Date Wed, 31 Oct 2012 21:31:13 GMT

     [ https://issues.apache.org/jira/browse/IO-355?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Uli Bubenheimer updated IO-355:
-------------------------------

    Summary: IOUtils copyLarge() and skip() methods are performance hogs  (was: IOUtils read()
and skip() methods are performance hogs)
    
> IOUtils copyLarge() and skip() methods are performance hogs
> -----------------------------------------------------------
>
>                 Key: IO-355
>                 URL: https://issues.apache.org/jira/browse/IO-355
>             Project: Commons IO
>          Issue Type: Bug
>          Components: Utilities
>    Affects Versions: 2.3, 2.4
>            Reporter: Uli Bubenheimer
>
> IOUtils.skip(InputStream, long) and IOUtils.skip(Reader, long) have the worst possible
performance as they always use read() on the input instead of using skip(). In many cases,
using skip() from a subclass of InputStream is much faster than read(), as the skip() can
be implemented via a disk seek.
> The IOUtils.skip() methods are used in the read() methods of IOUtils and their similarly
named siblings, so they tend to bring down the performance of all reads that involve a skip.
> Case in point: I have observed this performance degradation with Java 7 on Windows 7.
A series of consecutive reads on a large file on disk that involved skips changed my performance
from 30 secs as my baseline to 10 minutes after starting to use IOUtils.read().

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