On Tue, 20 Aug 2024 at 02:14, Kirill Reshke <reshkekir...@gmail.com> wrote:
> == Other thoughts > > In OLAP databases (see [2]), IVM opens the door for 'view > exploitation' feature. That is, use IVM (which is always up-to-date) > for query execution. But current IVM implementation is not compatible > with Cloudberry Append-optimized Table Access Method. The problem is > the 'table_tuple_fetch_row_version' call, which is used by > ivm_visible_in_prestate to check tuple visibility within a snapshot. I > am trying to solve this somehow. My current idea is the following: > multiple base table modification via single statement along with tuple > deletion from base tables are features. We can error-out these cases > (at M.V. creation time) all for some TAMs, and support only insert & > truncate. However, I don't know how to check if TAM supports > 'tuple_fetch_row_version' other than calling it and receiving > ERROR[3]. > I reread this and I find this a little bit unclear. What I'm proposing here is specifying the type of operations IVM supports on creation time. So, one can run CREATE IVM immv1 WITH (support_deletion = true/false, support_multiple_relation_change = true/false). Then, in the query execution time, we just ERROR if the query leads to deletion from IVM and support_deletion if false. -- Best regards, Kirill Reshke
