Not sure why you are getting downvoted here. Your question is very valid.

As far as the Techempower results go, I'm pretty sure it is not a GC issue. It could be the postgres implementation issue. Someone has to work with upstream to tune and fix the issues.

Contributing to such benchmarks require time and effort. A small community can do only so much in their free time.

Even though such benchmarks are good marketing, the D community is not interested in participating such benchmarks (although I'm quoting one post from the D forum, the trend is same).

https://forum.dlang.org/post/mailman.2866.1587920400.31109.d...