Use SIMEMBERS instead of SMEMBERS to check for queue (redis broker) (#1041)

* Add `_lookup_direct` method to virtual channel. (#994)

Add possibility to optimize lookup for queue in direct
exchange set.

* Add `_lookup_direct` method to redis virtual channel. (#994)

Use `SISMEMBER` instead of `SMEMBERS` command to check if queue
exists in a set. Time complexity is increased from O(N) to O(1)
where N is the set cardinality.

kombu/transport/redis.py

@@ -829,6 +829,24 @@ class Channel(virtual.Channel):
                 raise InconsistencyError(NO_ROUTE_ERROR.format(exchange, key))
             return [tuple(bytes_to_str(val).split(self.sep)) for val in values]
 
+    def _lookup_direct(self, exchange, routing_key):
+        if not exchange:
+            return [routing_key]
+
+        key = self.keyprefix_queue % exchange
+        pattern = ''
+        queue = routing_key
+        queue_bind = self.sep.join([
+            routing_key or '',
+            pattern,
+            queue or '',
+        ])
+        with self.conn_or_acquire() as client:
+            if client.sismember(key, queue_bind):
+                return [queue]
+
+        return []
+
     def _purge(self, queue):
         with self.conn_or_acquire() as client:
             with client.pipeline() as pipe:

kombu/transport/virtual/base.py

@@ -725,6 +725,22 @@ class Channel(AbstractChannel, base.StdChannel):
             R = [default]
         return R
 
+    def _lookup_direct(self, exchange, routing_key):
+        """Find queue matching `routing_key` for given direct `exchange`.
+
+        Returns:
+            str: queue name
+        """
+        if not exchange:
+            return [routing_key]
+
+        return self.exchange_types['direct'].lookup(
+            table=self.get_table(exchange),
+            exchange=exchange,
+            routing_key=routing_key,
+            default=None,
+        )
+
     def _restore(self, message):
         """Redeliver message to its original destination."""
         delivery_info = message.delivery_info

kombu/transport/virtual/exchange.py

@@ -65,7 +65,7 @@ class DirectExchange(ExchangeType):
         }
 
     def deliver(self, message, exchange, routing_key, **kwargs):
-        _lookup = self.channel._lookup
+        _lookup = self.channel._lookup_direct
         _put = self.channel._put
         for queue in _lookup(exchange, routing_key):
             _put(queue, message, **kwargs)

t/unit/transport/test_redis.py

@@ -88,6 +88,9 @@ class Client(object):
     def smembers(self, key):
         return self.sets.get(key, set())
 
+    def sismember(self, name, value):
+        return value in self.sets.get(name, set())
+
     def ping(self, *args, **kwargs):
         return True