> On Wed, Mar 2, 2016 at 6:54 PM, Alexander Korotkov > <a.korot...@postgrespro.ru> wrote: >> If FDWs existed then Postgres XC/XL were being developed then I believe they >> would try to build full-featured prototype of FDW based sharding. If this >> prototype succeed then we could make a full roadmap. > > Speaking here with my XC hat, that's actually the case. A couple of > years back when I worked on it, there were discussions about reusing > FDW routines for the purpose of XC, which would have been roughly > reusing postgres_fdw + the possibility to send XID, snapshot and > transaction timestamp to the remote nodes after getting that from the > GTM (global transaction manager ensuring global data visibility and > consistency), and have the logic for query pushdown in the FDW itself > when planning query on what would have been roughly foreign tables > (not entering in the details here, those would have not been entirely > foreign tables). At this point the global picture was not completely > set, XC being based on 9.1~9.2 and the FDW base routines were not as > extended as they are now. As history has told, this global picture has > never showed up, though it would should XC have been merged with 9.3. > The point is that XC would have moved as using the FDW approach, as a > set of plugins. > > This was a reason behind this email of 2013 on -hackers actually: > http://www.postgresql.org/message-id/cab7npqtdjf-58wuf-xz01nkj7wf0e+eukggqhd0igvsod4h...@mail.gmail.com > > There were as well discussions about making the connection pooler a > background worker and plug in that in a shared memory context that all > backends connecting to this XC-like-postgres_fdw would use, though > this is another story, for another time...
Thanks for the history. Very interesting... Best regards, -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese:http://www.sraoss.co.jp -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
