little sql help required

[Strong, Mark]

All,
	I've read the SQL_HOWTO, and have it working, however I'm trying to understand this bit in the example.

group {
   sql1 {
     fail  = 1
     notfound = return
     noop  = 2
     ok  = return
     updated = 3
     reject = return
     userlock = 4
     invalid = 5
     handled = 6
   }
   sql2 {
     fail  = 1
     notfound = return
     noop  = 2
     ok  = return
     updated = 3
     reject = return
     userlock = 4
     invalid = 5
     handled = 6
   }
 }

I've got two servers, each with its own mysql db (replicated to each other), and I'd like freeradius to fail over to the other boxes mysql server if its local one dies.

So I'd like to understand what that group mysql example does, before I paste it into my configs.  Looked at the docs, but can't find it (or something like it) described anywhere.

I've got version 2.1.6, on Centos 4.7

Regards
Mark Strong