Merge pull request #1099 from andyxning/lookupd_enhance_perf_for_node…

…s_api

lookupd: enhance performance for nodes api

nsqlookupd/http.go

@@ -265,17 +265,23 @@ func (s *httpServer) doNodes(w http.ResponseWriter, req *http.Request, ps httpro
 	producers := s.ctx.nsqlookupd.DB.FindProducers("client", "", "").FilterByActive(
 		s.ctx.nsqlookupd.opts.InactiveProducerTimeout, 0)
 	nodes := make([]*node, len(producers))
+	topicProducersMap := make(map[string]Producers)
 	for i, p := range producers {
 		topics := s.ctx.nsqlookupd.DB.LookupRegistrations(p.peerInfo.id).Filter("topic", "*", "").Keys()
 
 		// for each topic find the producer that matches this peer
 		// to add tombstone information
 		tombstones := make([]bool, len(topics))
 		for j, t := range topics {
-			topicProducers := s.ctx.nsqlookupd.DB.FindProducers("topic", t, "")
+			if _, exists := topicProducersMap[t]; !exists {
+				topicProducersMap[t] = s.ctx.nsqlookupd.DB.FindProducers("topic", t, "")
+			}
+
+			topicProducers := topicProducersMap[t]
 			for _, tp := range topicProducers {
 				if tp.peerInfo == p.peerInfo {
 					tombstones[j] = tp.IsTombstoned(s.ctx.nsqlookupd.opts.TombstoneLifetime)
+					break
 				}
 			}
 		}

nsqlookupd/registration_db.go

@@ -141,19 +141,21 @@ func (r *RegistrationDB) FindProducers(category string, key string, subkey strin
 		return ProducerMap2Slice(r.registrationMap[k])
 	}
 
-	results := make(map[string]*Producer)
+	results := make(map[string]struct{})
+	var retProducers Producers
 	for k, producers := range r.registrationMap {
 		if !k.IsMatch(category, key, subkey) {
 			continue
 		}
 		for _, producer := range producers {
 			_, found := results[producer.peerInfo.id]
 			if found == false {
-				results[producer.peerInfo.id] = producer
+				results[producer.peerInfo.id] = struct{}{}
+				retProducers = append(retProducers, producer)
 			}
 		}
 	}
-	return ProducerMap2Slice(results)
+	return retProducers
 }
 
 func (r *RegistrationDB) LookupRegistrations(id string) Registrations {