Remove PG load balancing.

We're moving to a different solution internally and
it's not helpful to smaller sites.

r2/r2/lib/manager/db_manager.py

@@ -111,71 +111,5 @@ class db_manager:
         if len(tables) == 1:
             return tables[0]
 
-        if self.dead:
-            tables = set(tables)
-            dead = set(t for t in tables if t[0].bind in self.dead)
-            for t in list(dead):
-                # TODO: tune the reconnect code.  We have about 1-2
-                # requests per second per app, so this should
-                # reconnect every 50-100 seconds.
-                if (random.randint(1,100) == 42 and 
-                    self.test_engine(t[0].bind)):
-                    dead.remove(t)
-            tables = tables - dead
-
-        #'t' is a list of engines itself. since we assume those engines
-        #are on the same machine, just take the first one. len(ips) may be
-        #< len(tables) if some tables are on the same host.
-        ips = dict((t[0].bind.url.host, t) for t in tables)
-        ip_loads = AppServiceMonitor.get_db_load(ips.keys())
-
-        total_load = 0
-        missing_loads = []
-        no_connections = []
-        have_loads = []
-
-        for ip in ips:
-            if ip not in ip_loads:
-                missing_loads.append(ip)
-            else:
-                load, avg_load, conns, avg_conns, max_conns = ip_loads[ip]
-
-                # remove high load machines from the pool.
-                if load < 100:
-                    max_load = max(load, avg_load)
-                    total_load += max_load
-                    have_loads.append((ip, max_load))
-                else:
-                    no_connections.append(ip)
-
-        if total_load:
-            avg_load = total_load / max(len(have_loads), 1)
-            ip_weights = [(ip, 1 - load / total_load) for ip, load in have_loads]
-        #if total_load is 0, which happens when have_loads is empty
-        else:
-            avg_load = 1.0
-            ip_weights = [(ip, 1.0 / len(have_loads)) for ip, load in have_loads]
-
-        if missing_loads or no_connections:
-            #add in the missing load numbers with an average weight
-            ip_weights.extend((ip, avg_load) for ip in missing_loads)
-
-            #add in the over-connected machines with a 1% weight
-            ip_weights.extend((ip, .01) for ip in no_connections)
-
-        #rebalance the weights
-        total_weight = sum(w[1] for w in ip_weights) or 1
-        ip_weights = [(ip, weight / total_weight)
-                      for ip, weight in ip_weights]
-
-        r = random.random()
-        for ip, load in ip_weights:
-            if r < load:
-                # print "db ip: %s" % str(ips[ip][0].metadata.bind.url.host)
-                return ips[ip]
-            r = r - load
-
-        #should never happen
-        print 'yer stupid'
         return  random.choice(list(tables))