Rust analyzer took 12GB of memory on zed project

[WalterScottYoung]

I'm trying to work on the zed editor project, and noticed that open the project with zed/vscode would lead to 12 GB memory usage in idle and at most 16GB when indexing， which is significantly more compared to clangd used in much bigger projects. I'm wondering if this is considered normal and if it is, why does rust analyzer needs so many memory and is there any cfg I could use to reduce the memory usage.

[ShoyuVanilla]

Rust is a more complicated language than C(or C++ in some parts) and rust-analyzer runs in an incremental way to reduce computing everything again and again from scratch so it caches some query results (e.g. trait solve) to salsa. I'm ignorant of clangd but that might explain why it is using more memory compared to clangd. But there are some reports that rust-analyzer tends to use more memory these days like #19402. As mentioned in that issue, we are currently on a final stage of trait solver migration and after that, we could deeply investigate which things are causing memory pressures and fix/mitigate them.