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https://issues.apache.org/jira/browse/TEZ-4185?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17116416#comment-17116416
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Ashutosh Chauhan commented on TEZ-4185:
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Thinking more about this, functionally there is no need to check umask while
setting permissions since you all always want to set permissions needed.
However, checking umask will provide a performance advantage since check is
in-memory and avoids a system call on local FS when its not needed. Seems like
after HADOOP-11347 conf's umask can also be used on local fs. So, from that
perspective I suggest to modify the patch to use correct {{conf}} to keep that
performance advantage.
> Tez may skip file permission update on intermediate output
> ----------------------------------------------------------
>
> Key: TEZ-4185
> URL: https://issues.apache.org/jira/browse/TEZ-4185
> Project: Apache Tez
> Issue Type: Bug
> Affects Versions: 0.9.2, 0.10.1, 0.9.3
> Reporter: Attila Magyar
> Assignee: Attila Magyar
> Priority: Major
> Attachments: TEZ-4185.1.patch
>
>
> Before updating file permissions TEZ check if the permission change is needed
> with the following conditional:
> {code:java}
> if
> (!SPILL_FILE_PERMS.equals(SPILL_FILE_PERMS.applyUMask(FsPermission.getUMask(conf))))
> {
> rfs.setPermission(filename, SPILL_FILE_PERMS);
> } {code}
> The problem is that the config object used by this conditional can be
> different than the config used by the file system (rfs). The reason for this
> is the underlaying file system instance cache in hadoop.
> Either we should remove this conditional altogether (it's a local file
> system, it won't generate NN calls) or modify it to use rfs.getConf().
> The end result is a file, which is not readable by the group, because the
> permission change was skipped due to the umask mismatch between the 2 configs.
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