Syntax:
UUID_SHORT()

Returns a "short" universal identifier as a 64-bit unsigned integer
(rather than a string-form 128-bit identifier as returned by the UUID()
function).

The value of UUID_SHORT() is guaranteed to be unique if the following
conditions hold:

o The server_id of the current host is unique among your set of master
  and slave servers

o server_id is between 0 and 255

o You do not set back your system time for your server between mysqld
  restarts

o You do not invoke UUID_SHORT() on average more than 16 million times
  per second between mysqld restarts

The UUID_SHORT() return value is constructed this way:

  (server_id & 255) << 56
+ (server_startup_time_in_seconds << 24)
+ incremented_variable++;

URL: http://dev.mysql.com/doc/refman/5.5/en/miscellaneous-functions.html

