In Postgres-XC, GTM assigns sequence value to all the transactions in its cluster. XC is a kind of tightly-coupled distributed system. In a loosely-coupled distributed system, where each database is autonomous, we may need another mechanism.
I've learned that logical replication (used to be bi-directional replication) people are doing this kind of work. Regards; ---------- Koichi Suzuki 2013/7/12 Joshua D. Drake <j...@commandprompt.com> > > On 07/12/2013 07:23 AM, Melvin Call wrote: > >> Hello list, >> >> Can anyone point me to some reading material on how auto-generated >> sequence primary keys are handled on distributed systems? I think the >> advice used to be to use GUIDs, but I thought I read somewhere that >> PostgreSQL now assigns a pool of numbers to each node when a sequence is >> implemented. I have searched the PostgreSQL 9.1.5 Documentation, but >> apparently my search terms are not quite what it takes, or dreamt that up. >> > > PostgreSQL itself does not support a distributed architecture. You may be > thinking of Postgres-XC? > > Sequences are local to each instances and it is not a pool, it is a 64bit > allocation for each sequence within the local node, generally constrained > only when called from the serial (big serial being 64 bits) type to 32 bits. > > Sincerely, > > Joshua D. Drake > > > > >> Thanks, >> Melvin >> > > > -- > Command Prompt, Inc. - http://www.commandprompt.com/ 509-416-6579 > PostgreSQL Support, Training, Professional Services and Development > High Availability, Oracle Conversion, Postgres-XC, @cmdpromptinc > For my dreams of your image that blossoms > a rose in the deeps of my heart. - W.B. Yeats > > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/**mailpref/pgsql-general<http://www.postgresql.org/mailpref/pgsql-general> >
