Prevent unnecessary database read by l3 agent

Fixes bug 1088129

Change-Id: I887facf321f3267c16c101a1448827f6c046bb2c

diff --git a/quantum/db/l3_db.py b/quantum/db/l3_db.py
index 10a51a4c27d570e0e70676dcb1a6ce70c5657ad5..04a7a8f228323c27218d6fb47a580adf4d70f89b 100644 (file)
--- a/quantum/db/l3_db.py
+++ b/quantum/db/l3_db.py
@@ -864,6 +864,8 @@ class L3_NAT_db_mixin(l3.RouterPluginBase):
             my_ports = subnet_id_ports_dict.get(fixed_ip['subnet_id'], [])
             my_ports.append(port)
             subnet_id_ports_dict[fixed_ip['subnet_id']] = my_ports
+        if not subnet_id_ports_dict:
+            return
         filters = {'id': subnet_id_ports_dict.keys()}
         fields = ['id', 'cidr', 'gateway_ip']
         subnet_dicts = self.get_subnets(context, filters, fields)