On Tue, May 1, 2018 at 12:27 PM, Stas Kelvich <s.kelv...@postgrespro.ru> wrote: > Here proposed a set of patches that allow achieving proper snapshot isolation > semantics in the case of cross-node transactions. Provided infrastructure to > synchronize snapshots between different Postgres instances and a way to > atomically commit such transaction with respect to other concurrent global and > local transactions. Such global transactions can be coordinated outside of > Postgres by using provided SQL functions or through postgres_fdw, which make > use > of this functions on remote nodes transparently.
I'm concerned about the provisioning aspect of this problem. Suppose I have two existing database systems with, perhaps, wildly different XID counters. On a certain date, I want to start using this system. Or conversely, I have two systems that are bonded together using this system from the beginning, and then, as of a certain date, I want to break them apart into two standalone systems. In your proposed design, are things like this possible? Can you describe the setup involved? -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
