Dear Tom.
> (I have some vague recollection that we discussed how to do that during
> the last go-round --- if you want to work on this, it'd be a good idea
> to look in the archives first.)
Ok. I found a thread initiated by you in january 2003. I read it quickly.
From a practical point of view, I wish I could download all messages from
this thread so as to do the reading in my mail user agent. Does not seem
possible from the web interface I found.
I don't like the idea of max(used user sysid) anyway, because if someone
creates a user with maxint, then createuser might be broken. Just for
the fun, with the current postgres:
psql> CREATE USER nobody WITH SYSID 2147483647; -- ((2**31)-1)
psql> CREATE USER bla;
-- yes, it works...
psql> CREATE USER wip;
ERROR: duplicate key violates unique constraint "pg_shadow_usesysid_index"
psql> SELECT usename, usesysid FROM pg_user;
...
nobody | 2147483647
bla | -2147483648
Warf!
I think that what is practical is to iterate through the sequence if some
user already exists. Collisions are unlikely, so it would not be
expensive.
So the only problem is to implement system-wide "cluster" sequences...
--
Fabien Coelho - coelho@cri.ensmp.fr