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potamictoday at 6:04 AM1 replyview on HN

Could you elaborate a bit on why RA's incremental approach takes more memory? Intuitively it feels that it should take less, because you're only processing what you need? Whereas you seem to indicate that you save a full analysis snapshot to disk and load it all up when needed? Shouldn't that consume the max memory for a workspace?

Fantastic project btw, and it couldn't come at a better time. With the way prices are going I really hope people start paying attention to memory again.


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popzxctoday at 6:08 AM

It's explained in the blog post, but in short: rust-analyzer stores the data it needs in memory all the time, while Rust Glancer might consume more memory during indexing (because it's not lazy and does more indexing), but after that it only loads _necessary_ information for the duration of the query.

Several things here: 1. We don't need all the information (project can have 1000+ dependencies, while query might only care about the current open file), so the amount of information we load is smaller. 2. Most of the time IDE does not actually do any queries, so if you switch to browser/Slack, you don't pay the tax. 3. Since data is loaded to the disk, after initial indexing restarting no longer consumes that much ram, and you get reindexing for free. 4. Besides offloading, I implement quite a bit of memory optimizations (some of which are covered in docs: https://rust-glancer.github.io/docs/development/MEMORY.html ), so it's a combination of factors.