MQTT Client Server Request Response

Question

Mobile apps are updating their location to server and server responds with content.

Is it possible to use MQTT (Apache Artemis) for sending real time location updates from mobile application to server.

In this case is it required my server application (PHP) to subscribe for a topic?

Server has to handle all location updates through a single subscribed channel. This may slow down the server right?

Flow is like - Android clients sends user's location periodically (E.g. 30Sec) to server and the PHP server returns nearest users and app displays them on the map.

Here is the architecture I was planned using MQTT Each mobile app users id will be considered as a topic so that we can send response to each user. PHP server will considered as a topic e.g. "LOCATION_TRACKER". All mobile apps publishes location to Server topic "LOCATION_TRACKER". Server prepares the list and publish response to individual user's by using their id as topics.

In this archetecture the PHP server suscribes for topic "LOCATION_TRACKER" and in fact all mobile apps are publishing to a single topic. Consider there are millions of users how to scale the PHP server or is there any other way of doing this?

The application will target at least 10 Million users. Should support half of concurrent users.

Answer 1

It is perfectly possible to send location updates from a mobile device to a MQTT broker, for an example look at the OwnTracks project.

For your seconds point, how a application behaves when processing a high volume of messages is entirely down to how that application architected. For high volume systems the usual pattern is to us a local queue and a thread pool to distribute the load, but it will all depend on what you need to do with the data.