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The "Hive/ViewDev" page has been changed by JohnSichi. http://wiki.apache.org/hadoop/Hive/ViewDev?action=diff&rev1=7&rev2=8 -------------------------------------------------- Note that besides table modifications, other operations such as CREATE OR REPLACE VIEW have similar issues (since views can reference other views). The lenient approach provides a reasonable solution for the related issue of external tables whose schemas may be dynamic (not sure if we currently support this). - '''Update 30-Dec-2009''': Based on a design review meeting, we'll start with the lenient approach, without any support for marking objects invalid in the metastore, then follow up with strict support and possibly metastore support for tracking object validity. + '''Update 30-Dec-2009''': Based on a design review meeting, we'll start with the lenient approach, without any support for marking objects invalid in the metastore, then if time allows, follow up with strict support and possibly metastore support for tracking object validity. == View Modification == @@ -119, +119 @@ '''Update 30-Dec-2009''': Based on feedback in JIRA, ORDER BY is important as forward-looking to materialized views. LIMIT may be less important, but we should probably support it too for consistency. + == Underlying Partition Dependencies == + + '''Update 30-Dec-2009''': Prasad pointed out that even without supporting materialized views, it may be necessary to provide users with metadata about data dependencies between views and underlying table partitions so that users can avoid seeing inconsistent results during the window when not all partitions have been refreshed with the latest data. One option is to attempt to derive this information automatically (using an overconservative guess in cases where the dependency analysis can't be made smart enough); another is to allow view creators to declare the dependency rules in some fashion as part of the view definition. Based on a design review meeting, we will probably go with the automatic analysis approach once dependency tracking is implemented. The analysis will be performed on-demand, perhaps as part of describing the view or submitting a query job against it. Until this becomes available, users may be able to do their own analysis either via empirical lineage tools or via view->table dependency tracking metadata once it is implemented. +
