3.6 regression: composite project build time is slower than in 3.5.3 #33161
Description
tsc --build in a composite project is a lot slower in version 3.6 than in 3.5.3.
I compared version 3.5.3 with version 3.6.2 and typescript@next (the next tag resolves to 3.7.0-dev.20190830 at the time of writing).
When I do a clean build, without any *.tsbuildinfo files, it takes about 65 seconds on all these versions.
When running the build step again, with the *.tsbuildinfo files, it takes about 6 seconds on version 3.5.3 and about 55 seconds on version 3.6.2 and typescript@next.
| version | clean build time | repeated build time |
|---|---|---|
3.5.3 |
~ 65 sec | ~ 6 sec |
3.6.2 |
~ 65 sec | ~ 55 sec |
@next |
~ 65 sec | ~ 55 sec |