Redundant expansions?

[Alan DeKok]

  So.. should redundant expansions go into 3.0.5?  They would work like
this:

instantiate {
	...

	redundant-load-balance my_sql {
		sql1
		sql2
		sql3
	}

}

  You can already use "my_sql" in the "authorize" section, which is
nice.  This feature would allow you to use "my_sql" in expansions:

	update reply {
		Filter-Id := "%{my_sql:SELECT ...}"
	}

  The server core will automatically find *one* of the listed modules
(sql1, sql2, or sql3), and call it.

  This feature has long been requested,and it's finally in the "master"
branch.  The question is whether it should go into the 3.0.5 release.

  Since the connection pools now support a "retry_delay" parameter, the
cost of querying a "down" SQL server is essentially zero.  In v2, the
server would usually try to reconnect to SQL for evcery request.

  In v3, the "retry_delay" makes the "redundant-load-balance" blocks
more useful.  SQL servers which are down are effectively remove from the
redundant list, until "retry_delay" seconds have passed.

  These changes increase the performance of the server, and make
problems much less notable.

  Alan DeKok.