Re: Authentication trick

antongiulio05@gmail.com wrote:
> My application is commercial. It uses postgresql. I want include in my-app a "protection-trick" retrieving a some kind of "unique system_identifier". Your pg_control file could be good, but it's a "data-file". How can I extract infos from it?

Sounds like a bad idea. system_identifier changes when you dump/restore 
to another installation. You don't want to forbid your users to restore 
from a backup, do you?

> Around same dir I have found these infos:
> 
> "myappdb" 20496 1663 3221455155 229682
> 
> Maybe are these the keys?

pg_database? No, don't mess with that. And those numbers are not 
guaranteed to be unique across installations.

I'd recommend trusting your users instead of adding limitations like 
that. They can be a real pain the ass if you're user wants to move his 
database to another server, run a warm-standby, backup/restore, run in a 
virtualized environment etc. and you don't want to cause hardship like 
that to your customers, do you?

If you still want to add a server key etc, I'd suggest creating user 
defined function that extracts a system identifier from somewhere else 
than the database.

-- 
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com