[bug] `tsgo --build` uses extreme amounts of memory

[mjames-c]

Stack trace

Unfortunately I don't have one to share as it crashed my remote dev machine (used 116GB of RSS before it did).

Steps to reproduce

This is probably unique to our scale here at Canva. I attempted to build one of the TS projects in our monorepo that transitively depends upon 5k+ other TS projects. It built for ~5 mins before crashing out due to excess memory usage.

./built/local/tsgo --build ../canva/<omitted>/tsconfig.json

[sheetalkamat]

Can you please try #1623 and see if that helps

[mjames-c]

@sheetalkamat I just tried it out again with your change included -- unfortunately still seems to be broken. memory climbed back up to 100GB RSS before the OS killed the process. we could try to take a pprof memory profile beginning of next week if you'd find it useful?

$ strings ./built/local/tsgo | grep -i 15ae26ccc
mod     github.com/microsoft/typescript-go      v0.0.0-20250822042943-15ae26cccfb7
build   vcs.revision=15ae26cccfb7cd863aa009d0171715721d6785e1

[johnnycheng0210]

@sheetalkamat

following up @mjames-c -- with profiles attached for one of our largest TS projects:

typescript-cpuprof.gz

typescript-memprof.gz

happy to provide some more profiles of smaller projects if that'll be useful as well.

[sheetalkamat]

@johnnycheng0210 can you see if you repro this if you run --singleThreaded

[sheetalkamat]

Can you try #1692 to see if it helps. You can also use --maxConcurrentProjects to change how many projects can be built simultaneously and see if that is of any help

[hsource]

@sheetalkamat We faced the same problem (even with --noEmit) of tsgo taking more memory than tsc. Using --singleThreaded resolved the problem, while still allowing us to take advantage of the performance gains. Thanks for the tip!

Edit: One additional thing that can be tuned is GOGC (see docs) and GOMEMLIMIT (see docs). We set GOGC to 0.3 and GOMEMLIMIT to something less than our CI servers' limit

[sheetalkamat]

Can you please try out #1745 to see if it helps

Thanks

[spanishpear]

@sheetalkamat have been seeing this too on a mix of individual projects or large subsets (8k projects) in our internal monorepo, how can I help test the PR? Build locally?

I might have missed where to find the branch deploy options 🙈🙏