--[[

   Copyright (C) 2007 MySQL AB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

--]]

module("proxy.balance", package.seeall)

function idle_failsafe_rw()
	local backend_ndx = 0

	for i = 1, #proxy.backends do
		local s = proxy.backends[i]
		local conns = s.pool.users[proxy.connection.client.username]
		
		if conns.cur_idle_connections > 0 and 
		   s.state ~= proxy.BACKEND_STATE_DOWN and 
		   s.type == proxy.BACKEND_TYPE_RW then
			backend_ndx = i
			break
		end
	end

	return backend_ndx
end

function idle_ro() 
	local max_conns = -1
	local max_conns_ndx = 0

	for i = 1, #proxy.backends do
		local s = proxy.backends[i]
		local conns = s.pool.users[proxy.connection.client.username]

		-- pick a slave which has some idling connections
		if s.type == proxy.BACKEND_TYPE_RO and 
		   s.state ~= proxy.BACKEND_STATE_DOWN and 
		   conns.cur_idle_connections > 0 then
			if max_conns == -1 or 
			   s.connected_clients < max_conns then
				max_conns = s.connected_clients
				max_conns_ndx = i
			end
		end
	end

	return max_conns_ndx
end