chris@xxxxxxxxxxxxxxxxxx (Chris Travers) writes: >>At least on Windows, the GUID is derived in part from the computers >>primary MAC address. No, it's not a guarantee, but it's pretty unlikely >>:-) > The danger is not that the MAC address will be duplicated, but that > other factors will lead to an MD5 collision. What factors? The 'random' portion comes _in addition to_ location information and a timestamp, so that for there to be a collision, you need to be generating thousands of GUIDs *per millisecond* on a given host. > Unless you can show me that there is a 1:1 correspondence of all > possible unique factors going into the GUID generation and the output, > then I will say it is still no guarantee. Read the RFC (4122). It shows how it works. > So you could use the Mac address of the machine, I guess, if you > wanted to.... That is one option; section 4.3 of the RFC suggests an alternative that is also likely to work. -- (format nil "~S@~S" "cbbrowne" "acm.org") http://www.ntlug.org/~cbbrowne/sap.html Rules of the Evil Overlord #78. "I will not tell my Legions of Terror "And he must be taken alive!" The command will be: ``And try to take him alive if it is reasonably practical.''" <http://www.eviloverlord.com/> ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
