Fabien COELHO <coelho@cri.ensmp.fr> writes:
> So the only problem is to implement system-wide "cluster" sequences...
We certainly can't extend the regular CREATE SEQUENCE command this way;
you can't create shared objects after initdb.
The "clean" way to handle this would be to extend the bootstrap command
parser to accept a command along the lines of CREATE [SHARED] SEQUENCE
and then add a file in src/include/catalog that defines the shared
user-id-generator sequence. (Look at how pg_shadow is created for
precedent.)
Not having looked recently, I have no idea how much pain is implied by
the preceding paragraph ;-). I'd be willing to accept cruder
compromises if that approach seems impractical, but please look to see
if it can be done nicely first.
regards, tom lane