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Date: Tue, 8 Mar 2011 06:56:59 +0000 (UTC)
From: "Todd Lipcon (JIRA)" <jira@apache.org>
To: common-dev@hadoop.apache.org
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Subject: [jira] Created: (HADOOP-7172) SecureIO should not check owner on
 non-secure clusters that have no native support
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SecureIO should not check owner on non-secure clusters that have no native support
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                 Key: HADOOP-7172
                 URL: https://issues.apache.org/jira/browse/HADOOP-7172
             Project: Hadoop Common
          Issue Type: Bug
          Components: io, security
    Affects Versions: 0.22.0
            Reporter: Todd Lipcon
            Priority: Critical
             Fix For: 0.22.0


The SecureIOUtils.openForRead function currently uses a racy stat/open combo if security is disabled and the native libraries are not available. This ends up shelling out to "ls -ld" which is very very slow. We've seen this cause significant performance regressions on clusters that match this profile.

Since the racy permissions check doesn't buy us any security anyway, we should just fall back to a normal "open" without any stat() at all, if we can't use the native support to do it efficiently.

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