On Sat, May 29, 2010 at 6:25 PM, David Fetter <david@xxxxxxxxxx> wrote: >> I wondering if write-able CTE's will be the silver bullet that will >> make rule based update-able views based multiple vertically >> partitioned table robust. By robust, I mean to elimination the >> update anomalies that can occur from the view point client side >> optimistic locking where the virtual row appears to be >> inconsistently updated. > > I'm not sure I understand. Sorry about that, unreadable text is was happens when I don't proof read before sending. > When the concurrency issues in writeable > CTEs get fixed, they could become a mechanism for doing what you > describe, but I suspect there would be significant work involved in > harnessing them to that task. Actually I wasn't aware of the concurrency issue of write-able CTE's. The concern I have specifically relates to update-able views that were based upon joined tables (using these views was an attempt to hide the complexity of Generalization Hierarchies from the client side application). Updates to these kinds of views can give the appearance of non-atom updates on the view's virtual row. Also, if the view's reported row update count doesn't match what the client side software expects, the client automatically rolls back the transaction and reports a concurrent update error. However, when this happens some of the underlying rule's update statements were in fact processed, so the refreshed row in the view appears to have an non-atomic update even though the client rolls back the transaction. The following email was my first discovery that these kinds of update-able view were not get-along well with client side optimistic locking. http://archives.postgresql.org/pgsql-odbc/2006-12/msg00029.php -- Regards, Richard Broersma Jr. Visit the Los Angeles PostgreSQL Users Group (LAPUG) http://pugs.postgresql.org/lapug -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
