store category recent tids for faster retrieval

src/categories/recentreplies.js

@@ -32,6 +32,39 @@ module.exports = function(Categories) {
 		], callback);
 	};
 
+	Categories.updateRecentTid = function(cid, tid, callback) {
+		async.parallel({
+			count: function(next) {
+				db.sortedSetCard('cid:' + cid + ':recent_tids', next);
+			},
+			numRecentReplies: function(next) {
+				db.getObjectField('category:' + cid, 'numRecentReplies', next);
+			}
+		}, function(err, results) {
+			if (err) {
+				return callback(err);
+			}
+
+			if (results.count < results.numRecentReplies) {
+				return db.sortedSetAdd('cid:' + cid + ':recent_tids', Date.now(), tid, callback);
+			}
+			async.waterfall([
+				function(next) {
+					db.getSortedSetRangeWithScores('cid:' + cid + ':recent_tids', 0, results.count - results.numRecentReplies, next);
+				},
+				function(data, next) {
+					if (!data.length) {
+						return next();
+					}
+					db.sortedSetsRemoveRangeByScore(['cid:' + cid + ':recent_tids'], '-inf', data[data.length - 1].score, next);
+				},
+				function(next) {
+					db.sortedSetAdd('cid:' + cid + ':recent_tids', Date.now(), tid, next);
+				}
+			], callback);
+		});
+	};
+
 	Categories.getRecentTopicReplies = function(categoryData, uid, callback) {
 		if (!Array.isArray(categoryData) || !categoryData.length) {
 			return callback();
@@ -39,7 +72,10 @@ module.exports = function(Categories) {
 
 		async.waterfall([
 			function(next) {
-				async.map(categoryData, getRecentTopicTids, next);
+				var keys = categoryData.map(function(category) {
+					return 'cid:' + category.cid + ':recent_tids';
+				});
+				db.getSortedSetsMembers(keys, next);
 			},
 			function(results, next) {
 				var tids = _.flatten(results);
@@ -62,45 +98,6 @@ module.exports = function(Categories) {
 		], callback);
 	};
 
-	function getRecentTopicTids(category, callback) {
-		var count = parseInt(category.numRecentReplies, 10);
-		if (!count) {
-			return callback(null, []);
-		}
-
-		if (count === 1) {
-			async.waterfall([
-				function (next) {
-					db.getSortedSetRevRange('cid:' + category.cid + ':pids', 0, 0, next);
-				},
-				function (pid, next) {
-					posts.getPostField(pid, 'tid', next);
-				},
-				function (tid, next) {
-					next(null, [tid]);
-				}
-			], callback);
-			return;
-		}
-
-		async.parallel({
-			pinnedTids: function(next) {
-				db.getSortedSetRevRangeByScore('cid:' + category.cid + ':tids', 0, -1, '+inf', Date.now(), next);
-			},
-			tids: function(next) {
-				db.getSortedSetRevRangeByScore('cid:' + category.cid + ':tids', 0, Math.max(1, count), Date.now(), '-inf', next);
-			}
-		}, function(err, results) {
-			if (err) {
-				return callback(err);
-			}
-
-			results.tids = results.tids.concat(results.pinnedTids);
-
-			callback(null, results.tids);
-		});
-	}
-
 	function getTopics(tids, callback) {
 		var topicData;
 		async.waterfall([

src/categories/topics.js

@@ -89,6 +89,9 @@ module.exports = function(Categories) {
 					db.sortedSetAdd('cid:' + cid + ':tids', postData.timestamp, postData.tid, next);
 				}
 			},
+			function(next){
+				Categories.updateRecentTid(cid, postData.tid, next);
+			},
 			function(next) {
 				db.sortedSetIncrBy('cid:' + cid + ':tids:posts', 1, postData.tid, next);
 			}

src/topics/create.js

@@ -63,6 +63,9 @@ module.exports = function(Topics) {
 							'cid:' + topicData.cid + ':uid:' + topicData.uid + ':tids'
 						], timestamp, topicData.tid, next);
 					},
+					function(next) {
+						categories.updateRecentTid(topicData.cid, topicData.tid, next);
+					},
 					function(next) {
 						user.addTopicIdToUser(topicData.uid, topicData.tid, timestamp, next);
 					},

src/upgrade.js

@@ -10,7 +10,7 @@ var db = require('./database'),
 	schemaDate, thisSchemaDate,
 
 	// IMPORTANT: REMEMBER TO UPDATE VALUE OF latestSchema
-	latestSchema = Date.UTC(2016, 8, 7);
+	latestSchema = Date.UTC(2016, 8, 22);
 
 Upgrade.check = function(callback) {
 	db.get('schemaDate', function(err, value) {
@@ -811,6 +811,45 @@ Upgrade.upgrade = function(callback) {
 				winston.info('[2016/08/07] Granting edit/delete/delete topic on existing categories - skipped!');
 				next();
 			}
+		},
+		function(next) {
+			thisSchemaDate = Date.UTC(2016, 8, 22);
+
+			if (schemaDate < thisSchemaDate) {
+				updatesMade = true;
+				winston.info('[2016/09/22] Setting category recent tids');
+
+
+				db.getSortedSetRange('categories:cid', 0, -1, function(err, cids) {
+					if (err) {
+						return next(err);
+					}
+
+					async.eachSeries(cids, function(cid, next) {
+						db.getSortedSetRevRange('cid:' + cid + ':pids', 0, 0, function(err, pid) {
+							if (err || !pid) {
+								return next(err);
+							}
+							db.getObjectFields('post:' + pid, ['tid', 'timestamp'], function(err, postData) {
+								if (err || !postData || !postData.tid) {
+									return next(err);
+								}
+								db.sortedSetAdd('cid:' + cid + ':recent_tids', postData.timestamp, postData.tid, next);
+							});
+						});
+					}, function(err) {
+						if (err) {
+							return next(err);
+						}
+
+						winston.info('[2016/09/22] Setting category recent tids - done');
+						Upgrade.update(thisSchemaDate, next);
+					});
+				});
+			} else {
+				winston.info('[2016/09/22] Setting category recent tids - skipped!');
+				next();
+			}
 		}
 		// Add new schema updates here
 		// IMPORTANT: REMEMBER TO UPDATE VALUE OF latestSchema IN LINE 24!!!