For over 20 years, millions of World of Warcraft players have battled through dungeons, conquered raids, and chased ever more powerful loot. But competition doesn’t end when the raid is over: leaderboards immortalize each achievement and step of progression, allowing players to see how they measure up. Founded in 2017, RaiderIO has become a household name for World of Warcraft players.

At the heart of RaiderIO are its leaderboards, which track millions of characters and hundreds of millions of completed dungeons across a variety of in-game challenges. These leaderboards empower players to see how they stack up against others of their same class, specialization, and a plethora of other dimensions.

With so many players depending on these rankings, maintaining speed, reliability, and accuracy is no small task and requires an infrastructure that can handle millions of queries without breaking a sweat.

Fast, Reliable Leaderboards That Players Can Trust

The RaiderIO team understands that responsiveness and availability of their services are critical to the gameplay experience for millions of players. Whether you’re checking player profiles as you fill out a group in the Dungeon Finder, or if you’re trying to view leaderboard rankings after defeating a new raid boss, players expect fast and accurate updates. Delivering a seamless experience year-round is a top priority!

RaiderIO’s leaderboards originally ran on Redis, using its powerful sorted set data structure for fast, efficient queries. While this setup performs well, the growing scale of RaiderIO’s leaderboards increased the operational complexity of managing these clusters due to the sheer quantity of data being ingested.

Scaling WoW’s Massive Data Without Breaking a Sweat

Each new WoW season brings a surge of fresh data as players push through the latest content. Combined with nearly a decade’s worth of historical leaderboards, RaiderIO has terabytes of leaderboard data that must be maintained.

This creates a significant capacity management challenge. Scaling Redis requires constant monitoring, provisioning, and maintenance to keep up with demand and ensure a stable service.

As this manually operated infrastructure grew, it was clear RaiderIO needed a better solution that could maintain speed and reliability without the constant upkeep– and without breaking the bank.

That’s where Momento came in.

By working with the Momento team, RaiderIO found a solution that delivered the right balance of cost, performance, and maintainability, eliminating the burdens of manual cluster management without compromising on speed or reliability.

Optimizing Ingestion Without Compromising Leaderboard Speed

RaiderIO ingests World of Warcraft data from multiple sources, including Blizzard’s API and direct streaming of game data from the RaiderIO Desktop App. This data must be processed and updated in real time to ensure leaderboards, character profiles, and guild profiles remain up to date.

At times throughout a season there will be a need for large-scale backfills of leaderboard data to recalculate rankings due to scoring algorithm changes. This demands a massive number of inserts into Redis sorted sets. However, Redis’ single-threaded nature makes this increasingly expensive as datasets grow, leading to longer insert times, increased queue backlogs, and greater contention between read and write operations. These challenges become even more pronounced as the leaderboards scale and player activity surges.

How Momento Supercharged RaiderIO’s Leaderboards

Managing leaderboards at this scale requires more than just fast queries. RaiderIO needed an infrastructure that could handle unpredictable spikes, scale dynamically, and remain cost-effective. By switching to Momento, the team was able to focus on building new features instead of maintaining infrastructure, ensuring players always have a fast and reliable experience. Data consistency was assured during migration by using a dual-write and dual-read validation process. Momento’s operations engineers were closely involved throughout the process, and helped alleviate performance bottlenecks from their previous infrastructure as a part of the migration. The true benefits showed up in the daily operations though, which went from regular upkeep headaches to being effortlessly managed.

Automated Scaling & Seamless Routing

Momento offers a powerful combination of intelligent control plane and seamless gateway functionality. The intelligent control plane proactively manages load and scale, adapting to dynamic demands from new WoW seasons and updated leaderboards by right-sizing instances, rebalancing server load, and automatically remediating unhealthy nodes. Complementing this, Momento’s gateway layer efficiently handles shard discovery and fan-outs for millions of concurrent client connections providing high availability, even during maintenance tasks. The gateway also integrates essential features such as authentication, access control, and support for multiple transport protocols, further streamlining operational complexities all without requiring RaiderIO team intervention.

Engineering Resilience for High Availability

RaiderIO’s traffic patterns spike by an order of magnitude or more during critical events, requiring downstream services like Momento to be able to absorb the traffic whilst serving low-latency reads. Momento replicates RaiderIO’s data to maintain fault tolerance and ensure high availability of upstream services. There’s a lot of machinery behind our storage servers that provide peak write throughput and low read latencies, while also keeping replicas up-to-date during critical events. Properly configuring in-memory buffers, streaming data efficiently over Momento’s protocol, and tuning system configurations all happen behind the scenes. The control plane’s role is critical which adds and rebalances capacity as the traffic changes. 

Conclusion

By offloading the complexities of leaderboard capacity management, routing, and ingestion performance to Momento, the RaiderIO team can focus on what matters most: building new & innovative features and delivering an even better experience for millions of World of Warcraft players. With Momento handling the infrastructure, RaiderIO is positioned to push the boundaries of community engagement and leaderboard innovation, ensuring WoW players always have the most comprehensive and reliable experience with tools players can depend upon to track their progress every step of the way.