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From Apache Wiki <wikidi...@apache.org>
Subject [Hadoop Wiki] Update of "Hive/Locking" by NamitJain
Date Wed, 05 May 2010 01:07:41 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.

The "Hive/Locking" page has been changed by NamitJain.
http://wiki.apache.org/hadoop/Hive/Locking?action=diff&rev1=1&rev2=2

--------------------------------------------------

  = Use Cases =
  
+ Concurrency support (http://issues.apache.org/jira/browse/HIVE-1293) is a must in databases
and their usecases are well understood. At a minimum, we want to support concurrent readers
and writers whenever possible.
+ It would be useful to add a mechanism to discover the current locks which have been acquired.
- Views (http://issues.apache.org/jira/browse/HIVE-972) are a standard DBMS feature and their
uses are well understood.  A typical use case might be to create an interface layer with a
consistent entity/attribute naming scheme on top of an existing set of inconsistently named
tables, without having to cause disruption due to direct modification of the tables.  More
advanced use cases would involve predefined filters, joins, aggregations, etc for simplifying
query construction by end users, as well as sharing common definitions within ETL pipelines.
- 
- = Scope =
- 
- At a minimum, we want to 
- 
-  * add queryable view support at the SQL language level (specifics of the scoping are under
discussion in the Issues section below)
-   * updatable views will not be supported
-  * make sure views and their definitions show up anywhere tables can currently be enumerated/searched/described
-  * where relevant, provide additional metadata to allow views to be distinguished from tables
- 
- Beyond this, we may want to
- 
-  * expose metadata about view definitions and dependencies (at table-level or column-level)
in a way that makes them consumable by metadata-driven tools
  
  = Syntax =
  

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