Well, while I only work on the Android client, the solution currently in use is a large codebase of code specifically written for this single purpose. In C++. Compiled natively. That’s the main reason why good performance with the system is even possible.
A huge performance boost (reconnection times down from ~2 minutes to ~12 seconds on 64kbps 2G network, using a Nexus 5X) could be accomplished by using Java NIO with non-copying IO for parsing the custom binary protocol, but we’re looking into using flat protobufs for improving performance further.
But then the database layer becomes the bottleneck. SQLite is far too slow to be normally usable, most users use PostgreSQL for the backing database.
Basically, the trick is in "don’t use JSON and JS, do stuff with native code and binary protocols to reduce overhead".
But this makes maintenance basically impossible, and isn’t really ideal either.
DISCLAIMER: I do not speak for the Quassel project, all opinions represented here are solely my own.
A huge performance boost (reconnection times down from ~2 minutes to ~12 seconds on 64kbps 2G network, using a Nexus 5X) could be accomplished by using Java NIO with non-copying IO for parsing the custom binary protocol, but we’re looking into using flat protobufs for improving performance further.
But then the database layer becomes the bottleneck. SQLite is far too slow to be normally usable, most users use PostgreSQL for the backing database.
Basically, the trick is in "don’t use JSON and JS, do stuff with native code and binary protocols to reduce overhead".
But this makes maintenance basically impossible, and isn’t really ideal either.
DISCLAIMER: I do not speak for the Quassel project, all opinions represented here are solely my own.