Am Monday, 28. July 2008 schrieb Tom Lane:
> But to define such a domain, you'd have to commit to a case-insensitive
> version of a specific collation, no? citext currently means "case
> insensitive version of whatever the database's default collation is".
So in the future, someone using citext with lc_collate = en_US attempting to
upgrade would then define
CREATE DOMAIN citext AS text COLLATION "en_US(at)ci"
And yes, you would potentially have different definitions of this citext
domain in different database clusters, depending on what configuration you
are upgrading from, but I don't see that as a problem. It is the natural
thing to do.