[jira] [Commented] (DRILL-4990) Use new HDFS API access instead of listStatus to check if users have permissions to access workspace.

["Kunal Khatua (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/DRILL-4990?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15877280#comment-15877280 ] 

Kunal Khatua commented on DRILL-4990:
-------------------------------------

[~ppenumarthy] What were the test issues that needed to be resolved?

> Use new HDFS API access instead of listStatus to check if users have permissions to access workspace.
> -----------------------------------------------------------------------------------------------------
>
>                 Key: DRILL-4990
>                 URL: https://issues.apache.org/jira/browse/DRILL-4990
>             Project: Apache Drill
>          Issue Type: Bug
>          Components: Query Planning & Optimization
>    Affects Versions: 1.8.0
>            Reporter: Padma Penumarthy
>            Assignee: Padma Penumarthy
>             Fix For: 1.9.0
>
>
> For every query, we build the schema tree (runSQL->getPlan->getNewDefaultSchema->getRootSchema). All workspaces in all storage plugins are checked and are added to the schema tree if they are accessible by the user who initiated the query.  For file system plugin, listStatus API is used to check if  the workspace is accessible or not (WorkspaceSchemaFactory.accessible) by the user.  The idea seem to be if the user does not have access to file(s) in the workspace, listStatus will generate an exception and we return false. But, listStatus (which lists all the entries of a directory) is an expensive operation when there are large number of files in the directory. A new API is added in Hadoop 2.6 called access (HDFS-6570) which provides the ability to check if the user has permissions on a file/directory.  Use this new API instead of listStatus. 



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