On Tue, 23 Jun 2020 at 13:26, Amit Kapila <amit.kapil...@gmail.com> wrote: > > On Tue, Jun 23, 2020 at 9:03 AM Masahiko Sawada > <masahiko.saw...@2ndquadrant.com> wrote: > > > > > > I've attached the latest version patches. I've incorporated the review > > comments I got so far and improved locking strategy. > > > > Thanks for updating the patch. > > > Please review it. > > > > I think at this stage it is important that we do some study of various > approaches to achieve this work and come up with a comparison of the > pros and cons of each approach (a) what this patch provides, (b) what > is implemented in Global Snapshots patch [1], (c) if possible, what is > implemented in Postgres-XL. I fear that if go too far in spending > effort on this and later discovered that it can be better done via > some other available patch/work (maybe due to a reasons like that > approach can easily extended to provide atomic visibility or the > design is more robust, etc.) then it can lead to a lot of rework.
Yeah, I have no objection to that plan but I think we also need to keep in mind that (b), (c), and whatever we are thinking about global consistency are talking about only PostgreSQL (and postgres_fdw). On the other hand, this patch needs to implement the feature that can resolve the atomic commit problem more generically, because the foreign server might be using oracle_fdw, mysql_fdw, or other FDWs connecting database systems supporting 2PC. Regards, -- Masahiko Sawada http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
