Real-Time Systems on Prateek Sharma

Two-sided membership needs one lock, not two

Thu, 27 Aug 2026 00:00:00 +0000

Goroomlib models a relationship that points both ways: a Room holds a map of its users, and each User holds a list of the rooms it’s in. That redundancy is deliberate — both lookups need to be O(1) — but it’s also the whole bug surface.

The first version

AddUserToRoom did the obvious thing:

func (s *RoomService) AddUserToRoom(roomName string, user *User) {
    room := s.rooms[roomName]

    room.mu.Lock()
    room.users[user.ID] = user
    room.mu.Unlock()

    user.mu.Lock()
    user.joinedRooms = append(user.joinedRooms, roomName)
    user.mu.Unlock()
}

Each side is individually locked, so go vet and the race detector on a simple test are both happy. But there’s a window between the two critical sections where the room says “user is here” and the user says “I’m not in that room.” Anything that reads both — say, a disconnect handler that walks user.joinedRooms to remove the user from each — can run in that window and leak the membership.

Goroomlib

Sun, 23 Aug 2026 00:00:00 +0000

Across the poker platforms I’ve worked on at Adda52 and Mind Sports League, one shape kept showing up: users joining a table, leaving it, sending messages to everyone at it, and the server keeping track of who’s where. Every time I touched a new real-time feature, I ended up rewriting the same User and Room bookkeeping from scratch. I wanted to pull that pattern out once, get it right, and stop reimplementing it.

Mind Sports League

Mon, 01 Mar 2021 00:00:00 +0000

Mind Sports League ran an online poker platform. I led development of the game and tournament features on top of the existing platform.

Engineering areas

Tournament features

Built advanced tournament mechanics: hand-for-hand play, re-entry, and table balancing.

Real-time backend

Engineered game-state management and an event-driven backend handling thousands of concurrent players with low-latency communication.

Training tools

Built a poker simulator integrated with an educational platform, so players could practise strategy and review analytics.

Stack

Real-time / event-driven backend · game-state management · AngularJS (simulator)

Adda52 — Delta Corp

Mon, 01 Sep 2014 00:00:00 +0000

Adda52 is one of India’s largest real-money poker platforms. I joined as a graduate trainee in 2014 and left in 2020 as a Senior Software Engineer, working across the game backend, load and resilience testing, and the public platform.

Role progression

Graduate Engineer Trainee (Sep 2014 – Oct 2015)
Software Engineer (Oct 2015 – Oct 2016)
Senior Software Engineer (Oct 2016 – Feb 2020)

Engineering areas

Game logic

Contributed to core poker cash-game and tournament-management modules.
Implemented the OFC poker variant end to end on the adda52live.com frontend (Angular 2).

Load and resilience testing

Enhanced Java-based user-behaviour simulators to load test real-time poker servers at 10,000+ concurrent users.
Built disaster-recovery systems for zero-downtime gameplay — restoring poker games and player state after a failure.

Platform migration

Led migration of the public gaming platform from PHP to Node.js, improving performance and maintainability.
Built Angular 2 interfaces for event bookings on adda52live.com and user-segmentation logic for targeted marketing.

Delivery

Developed Gradle-based CI/CD pipelines with Jenkins, automating builds and reducing integration friction.
Represented a 6-member team in sprint planning and stakeholder meetings, coordinating with QA, product, and DevOps.

Stack

Java · Node.js · Angular 2 · Jenkins · Gradle