Dear Wiki user, You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.
The "Hive/PartitionedViews" page has been changed by JohnSichi. http://wiki.apache.org/hadoop/Hive/PartitionedViews?action=diff&rev1=11&rev2=12 -------------------------------------------------- = Use Cases = - 1. An administrator wants to create a set of views as a table/column renaming layer on top of an existing set of base tables, without disturbing the ETL processes which load those tables. To read-only users, the views should behave exactly the same as the underlying tables in every way. Among other things, this means users should be able to browse available partitions. + 1. An administrator wants to create a set of views as a table/column renaming layer on top of an existing set of base tables, without breaking any existing dependencies on those tables. To read-only users, the views should behave exactly the same as the underlying tables in every way. Among other things, this means users should be able to browse available partitions. 1. A base table is partitioned on columns (ds,hr) for date and hour. Besides this fine-grained partitioning, users would also like to see a virtual table of coarse-grained (date-only) partitioning in which the partition for a given date only appears after all of the hour-level partitions of that day have been fully loaded. 1. A view is defined on a complex join+union+aggregation of a number of underlying base tables and other views, all of which are themselves partitioned. The top-level view should also be partitioned accordingly, with a new partition not appearing until corresponding partitions have been loaded for all of the underlying tables.
