> Regarding the licencing of the code, I always release my code
> under GPL, which is the licence I prefer, but my code in the
> backend is obviously released under the original postgres
> licence. Since the module is loaded dynamically and not linked
> into the backend I don't see a problem here.
The problem is how to use user-locks in commercial projects.
Some loadable interface functions are required to use in-backend
user lock code, but interface is so simple - if one would write
new functions they would look the same as yours covered by GPL.
> If the licence becomes a problem I can easily change it, but
> I prefer the GPL if possible.
Actually I don't see why to cover your contrib module by GPL.
Not so much IP (intellectual property) there. Real new things
which make new feature possible are in lock manager.
Vadim