optimize queries

src/groups.js

@@ -439,15 +439,13 @@
 	};
 
 	Groups.getUserGroups = function(uids, callback) {
-		var ignoredGroups = ['registered-users'];
-
 		db.getSetMembers('groups', function(err, groupNames) {
 			if (err) {
 				return callback(err);
 			}
 
 			var groupKeys = groupNames.filter(function(groupName) {
-				return ignoredGroups.indexOf(groupName) === -1;
+				return groupName !== 'registered-users' && groupName.indexOf(':privileges:') === -1;
 			}).map(function(groupName) {
 				return 'group:' + groupName;
 			});

src/posts.js

@@ -404,15 +404,25 @@ var async = require('async'),
 
 			var tids = posts.map(function(post) {
 				return post.tid;
+			}).filter(function(tid, index, array) {
+				return array.indexOf(tid) === index;
 			});
 
 			topics.getTopicsFields(tids, ['cid'], function(err, topics) {
 				if (err) {
 					return callback(err);
 				}
-				var cids = topics.map(function(topic) {
+				var map = {};
-					return topic.cid;
+				topics.forEach(function(topic) {
+					if (topic) {
+						map[topic.tid] = topic.cid;
+					}
 				});
+
+				var cids = posts.map(function(post) {
+					return map[post.tid];
+				})
+
 				callback(null, cids);
 			});
 		});

src/topics.js

@@ -348,7 +348,7 @@ var async = require('async'),
 				return callback(err);
 			}
 
-			var postKeys = pids.map(function(pid) {
+			var postKeys = pids.filter(Boolean).map(function(pid) {
 				return 'post:' + pid;
 			});
 
@@ -379,14 +379,19 @@ var async = require('async'),
 					results.users.forEach(function(user) {
 						users[user.uid] = user;
 					});
-
+					var tidToPost = {};
 					postData.forEach(function(post, index) {
 						post.user = users[post.uid];
 						post.index = results.indices[index] + 1;
 						post.timestamp = utils.toISOString(post.timestamp);
+						tidToPost[post.tid] = post;
+					});
+
+					var teasers = tids.map(function(tid) {
+						return tidToPost[tid];
 					});
 
-					callback(null, postData);
+					callback(null, teasers);
 				});
 			});
 		});