@damian-gÄ…dziak Maybe you can try to debug by adding this in that function console.log(tids.length, uid, new Error('test').stack);
Topics.filterWatchedTids = function (tids, uid, callback) { console.log(tids.length, uid, new Error('test').stack); async.waterfall([ function (next) { db.sortedSetScores('uid:' + uid + ':followed_tids', tids, next); }, function (scores, next) { tids = tids.filter(function (tid, index) { return tid && !!scores[index]; }); next(null, tids); }, ], callback); };I am guessing the function is called by a huge amount of tids, so the next step would be to find out why and from where.