Caching

The Expo Open OTA server uses a cache to improve performance and reduce server load by avoiding repeated computations.

Cache Usage

The cache is primarily used for:

1. Storing the computed lastUpdateId for a given platform and runtime version

   • This prevents the need to recompute the last update for every request, significantly speeding up responses.

2. Caching the computed manifest

   • Manifest generation can be an expensive operation.
   • By caching the results, we reduce response times and improve overall performance.

Current Limitations

Currently, the cache is local to the server instance. This means:

• When a new update is published, the first request for the manifest may take longer as the cache needs to be repopulated.
• The cache is not shared across multiple instances, which could lead to inconsistent results in a distributed setup.

Future Improvements

We plan to implement a distributed caching system, such as Redis, to:

• Share cached results across multiple instances.
• Ensure consistent and faster responses regardless of the server handling the request.

Once the distributed cache is in place, performance will be significantly improved, especially for high-traffic environments.