Per-server univocal identifier

Dears,

I'm looking for a way to univocally identify the server on which a sql function or statement is running. My idea would
besomething close to the value returned by a 'host -f' under linux: the FQDN of the host, but even a serial code or a
numberwould be fine to me. It needs only to be immutable, I guess. 

I know there is something suitable under Oracle and, even worse, under mysql...

The purpose is mostly related to a light replication problem I have, in which I need to 'emulate' a multi-master
replicationon a table. 

I placed a question on the IRC list and I found a couple of unreplied messages asking the same thing in the
pgsql-generallist. 

Regards,

-----------------------------------
Giampaolo Tomassoni - IT Consultant
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I-53044 Chiusi (SI) - Italy
Ph: +39-0578-21100