node.js + mongodb + 2个不同的find（）查询

Question

我正在尝试在我的代码中执行2个find（）查询，每个查询都在一个单独的mongo集合中。 'profiles'查询工作正常，但是当我添加'thresholds'查询时，一切都会中断，我的admin.storeSession永远不会被调用。知道这是什么问题吗？

var targetCollection = udb.collection('profiles');
    var tc2 = udb.collection('thresholds');

targetCollection.ensureIndex({username: 1}, {unique : true}, function(err){     //set username to unique in 'profiles'
    if (!err){
        targetCollection.find({username: uname}).toArray(function(err, results) {      //search for profile doc that matches username
            if( err || !results.length)     //no document found
                console.error(err);
            else {
                if (bcrypt.compareSync(pw, results[0].password)){       //compare password to hashed bcrypt password in record
                    console.log("login success");
                    admin.storeSession(request, results, function(err){     //store the user's document in the session store
                        if (err)
                            console.error(err);
                    });
                    console.log('MARKER');
                    tc2.find({username: uname}).toArray(function(err, results) {      //search for profile doc that matches username
                        if( err || !results.length)     //no document found
                            console.log(err);
                        else {
                            console.log("Found threshold doc");
                            admin.storeThresholds(request, results, function(err){     //store the user's document in the session store
                                if (err)
                                    console.error(err);
                            });
                        }
                    });
                }
                else
                    console.log('Password hash does not match in system.');
            }
            response.redirect('/dashboard');
            udb.close();
        });
    }