On 02.04.23 19:46, Tomas Vondra wrote:
OK, I took a stab at this, see the attached 0007 patch which bumps the
protocol version, and allows the subscriber to specify "sequences" when
starting the replication, similar to what we do for the two-phase stuff.
The patch essentially adds 'sequences' to the replication start command,
depending on the server version, but it can be overridden by "sequences"
subscription option. The patch is pretty small, but I wonder how much
smarter this should be ...
I think this should actually be much simpler.
All the code needs to do is:
- Raise protocol version (4->5) (Your patch does that.)
- pgoutput_sequence() checks whether the protocol version is >=5 and if
not it raises an error.
- Subscriber uses old protocol if the remote end is an older PG version.
(Your patch does that.)
I don't see the need for the subscriber to toggle sequences explicitly
or anything like that.
