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It is important to realize that Hive Metastore only controls authorization for metadata, and the underlying data is controlled by HDFS, so if permissions and privileges between the two systems are not in sync, users may have access to metadata, but not the physical data. If the user -> group mappings across the Metastore and Namenode are not in sync, as in the scenarios above, a user may have the privileges required to access a table according to the Metastore, but may not have permission to access the underlying files according to the Namenode. This could also happen due to administrator intervention, if permissions on the files were changed by hand, but Metastore grants had not been updated.

Names of Users and Roles

Role names are case insensitive. That is, “marketing” and “MarkEting” refer to same role.

User names are case sensitive. This is because, unlike role names, user names are not managed within Hive.

Quoted Identifiers

User and role names may optionally be surrounded by back-tick characters (`) when the configuration parameter hive.support.quoted.identifiers is set to column (default value). All Unicode characters are permitted in the quoted identifiers. However when hive.support.quoted.identifiers is set to none, only alphanumeric and underscore characters are permitted in user names and role names.

For details, see HIVE-6013 and Supporting Quoted Identifiers in Column Names.

Creating/Dropping/Using Roles

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