On Wed, 9 Sep 2020 14:22:28 +1200 Thomas Munro <thomas.mu...@gmail.com> wrote:
> > Therefore, usual update semantics (tuple locks and EvalPlanQual) and UPSERT > > can be used for optimization for some classes of view, but we don't have any > > other better idea than using table lock for views joining tables. We would > > appreciate it if you could suggest better solution. > > I have nothing, I'm just reading starter papers and trying to learn a > bit more about the concepts at this stage. I was thinking of > reviewing some of the more mechanical parts of the patch set, though, > like perhaps the transition table lifetime management, since I have > worked on that area before. Thank you for your interrest. It would be greatly appreciated if you could review the patch. > > > (Newer papers describe locking schemes that avoid even aggregate-row > > > level conflicts, by taking advantage of the associativity and > > > commutativity of aggregates like SUM and COUNT. You can allow N > > > writers to update the aggregate concurrently, and if any transaction > > > has to roll back it subtracts what it added, not necessarily restoring > > > the original value, so that nobody conflicts with anyone else, or > > > something like that... Contemplating an MVCC, no-rollbacks version of > > > that sort of thing leads to ideas like, I dunno, update chains > > > containing differential update trees to be compacted later... egad!) > > > > I am interested in papers you mentioned! Are they literatures in context of > > incremental view maintenance? > > Yeah. I was skim-reading some parts of [1] including section 2.5.1 > "Concurrency Control", which opens with some comments about > aggregates, locking and pointers to "V-locking" [2] for high > concurrency aggregates. There is also a pointer to G. Graefe and M. > J. Zwilling, "Transaction support for indexed views," which I haven't > located; apparently indexed views are Graefe's name for MVs, and > apparently this paper has a section on MVCC systems which sounds > interesting for us. > > [1] https://dsf.berkeley.edu/cs286/papers/mv-fntdb2012.pdf > [2] http://pages.cs.wisc.edu/~gangluo/latch.pdf Thanks for your information! I will also check references regarding with IVM and concurrency control. Regards, Yugo Nagata -- Yugo NAGATA <nag...@sraoss.co.jp>
