Stateful v. Stateless Design: Key Considerations for Game Developers

The Power of Stateful Design for Game Backends

Our stateful design philosophy introduces the concept of maintaining a persistent state within game servers. In contrast to stateless systems where each request is treated in isolation, our approach adopts an actor-based model, which is better suited for handling games at large scale.

Here's a closer look at how it operates:

Authoritative Game Servers in a Stateful Architecture

Within the framework of stateful design, individual game servers function as the authoritative source of state. When an actor -- a player, guild, or any other in-game entity -- awakens from the database, the game server assumes responsibility for managing its state.

Periodic Data Persistence for State Safety

To safeguard against data loss, we implement periodic data persistence, ensuring that interactions among all actors within the clustered game server backend proceed seamlessly.

While critics contend that this approach can add complexity to scaling, its benefits far outweigh the challenges it presents.

Key Benefits of Stateful Design for Game Servers

1. Efficiency Gains and Reduced Database Load

One of the primary strengths of stateful design lies in the efficiency gains it delivers. By transforming the database into a simplified key-value store, we eliminate the need for every game operation to query the database, resulting in a substantial reduction in the database workload.

Consider the typical 9-to-1 ratio of read to write operations in many systems. With our stateful design, we often achieve a 1:1 ratio, alleviating the need to maintain eight additional read replicas. This not only enhances efficiency but also leads to significant cost savings.

2. Scalability and Streamlined Architecture

In the realm of game development, addressing scalability is paramount. Our stateful design supports database layer expansion through sharding into multiple database clusters. This ensures that we can scale database clusters without encountering capacity limitations.

Moreover, this design simplifies our overall architecture. When concerns arise about database performance, many developers opt for in-memory caching systems such as Redis or Memcached. In our architecture, we can circumvent these components entirely. Our game server application layer guarantees that actors continuously reflect the latest, up-to-date state of the game world, eliminating the need for additional caching layers.

Stateless Design: Limitations for Mobile Game Development

Now, let's briefly consider stateless design -- a methodology that has gained significant traction over the past decade. Stateless backends are known for their simplicity and ease of operation.

Each request is processed independently, making them suitable for various applications. However, when applied to the unique demands of mobile game development, stateless design may present certain limitations.

Games often involve numerous actors and complex interactions, requiring frequent access to shared states. In such scenarios, stateless designs may lead to increased database load and latency, potentially impacting gameplay experiences.

Choosing the Right Backend Architecture for Your Game

In summary, the choice between stateful and stateless designs for your game's backend infrastructure hinges on the specific requirements of your project.

Stateless designs offer simplicity and are suitable for various applications, but they may fall short in the context of mobile game development, where efficient state management and reduced database load are paramount.

Stateful design, as exemplified by Metaplay, introduces efficiency gains, reduces database load, ensures scalability, and simplifies architecture. These advantages make it an appealing choice, especially in mobile game development, where performance and cost-effectiveness are of utmost importance as a game scales.

When deciding between stateful and stateless designs, carefully assess your game's unique demands and player experience objectives. The choice you make will significantly influence the gameplay experience and operational efficiency of your mobile game.

Stateful vs. Stateless Game Backend Design FAQ

What is the difference between stateful and stateless game backend design?

In stateful design, game servers maintain persistent state for entities (players, guilds, etc.) in memory, acting as the authoritative source of truth. In stateless design, each request is processed independently without retaining state between requests, requiring frequent database queries to retrieve current game state.

Why does stateful design reduce database load for games?

Stateful design transforms the database into a simplified key-value store, eliminating the need for every game operation to query the database. This can reduce the typical 9-to-1 read-to-write ratio down to 1:1, removing the need for multiple read replicas and resulting in significant cost savings.

Can stateful game servers still scale to millions of players?

Yes. Stateful design supports database layer expansion through sharding into multiple database clusters. The game server application layer maintains up-to-date state for all actors, eliminating the need for caching layers like Redis or Memcached that add complexity to stateless architectures.

When should a game developer choose stateless over stateful design?

Stateless designs are suitable for simpler applications or games with minimal shared state requirements. However, for mobile games with numerous actors, complex interactions, and frequent state access needs, stateful design typically offers better performance, lower latency, and more cost-effective scaling.