Query not giving updated result after database update in mongoDB - node.js

Question

I have a server setup in node.js that uses mongoose. The problem i am having is that when i update a database as follows
Questions.update({id:questionID}, {$push: {answers: {answer:answer,answeredBy:username}}}, callback);
I see that the data has been added in MongoCompass but when i query it using
Questions.find({tags:interests},callback);
the updated data is not returned. But if i restart the server and again query, i receive the updated result.
And if i just save the data and query by using .save method and query, the database is updated.
So the problem has to be with my .update method right? I really cant find what i am doing wrong
my database is as follows
let mongoose =new require('mongoose');
const uuidv4 = require('uuid/v4');
//Define a schema
let Schema = mongoose.Schema;
let QuestionsSchema = new Schema({
id: {
type: String,
unique: true
},
title: String,
details: String,
askedDate: {type: Date, default: Date.now},
tags: [{
type: String
}],
askedBy: String,
answers: [{
answeredBy: String,
answer: String,
answeredDate: {type: Date, default: Date.now}
}]
});
let Questions = module.exports = mongoose.model('Questions', QuestionsSchema);
module.exports.addQuestion = function (newQuestion, callback) {
//generating a new random id for each question
newQuestion.id = uuidv4();
newQuestion.save(callback);
};
module.exports.addAnswer = function (username,answer, questionID, callback) {
Questions.update({id:questionID}, {$push: {answers: {answer:answer,answeredBy:username}}}, callback);
};
module.exports.getQuestions = function (interests, callback) {
Questions.find({tags:interests},callback);
};
The methods are called as follows
Questions.getQuestions(user.tags[i], function (err, questions) {
if (err) {
let output = {
error: {
status: "fail",
name: err.name,
message: err.message,
text: err.toString()
}
};
let statusCode = err.status || 500;
res.json(output);
res.send();
}
else {
questions.map((data) => {
if (!sentTags.includes(data.id)) {
jsonResponse.push(data);
sentTags.push(data.id);
}
});
if (i === user.tags.length - 1) {
res.send(JSON.parse(JSON.stringify(jsonResponse)));
}
}
});
and
Questions.addAnswer(user.username,req.body.answer, req.body.id, function (err) {
if (err) {
let output = {
error: {
status: "fail",
name: err.name,
message: err.message,
text: err.toString()
}
};
let statusCode = err.status || 500;
res.status(statusCode).json(output);
res.send();
}
else {
res.json({status: "success", message: "Answer Added"});
res.send();
}
});

Answer 1

Since MongoDB is eventually consistent, if the Question is saved and then immediately updated, it could be the case that the changes haven't been fully propagated yet.
In Mongoose, try specifying the read concern to 'primary' with this:
Questions.find({tags:interests}).read('p').exec(callback)
How to specify read concerns in Mongoose
MongoDB Read Concern documentation
Depending on the use-case, you may also want to explore the write concerns:
MongoDB Write Concerns