First, I would avoid using any low-level language if at all possible, because no matter what you pick, the maintenance and evolution costs are going to be significantly higher than for a high-level language. It's a very costly commitment, so I'd want to be sure it's worth it. But let's suppose I decided that I must use a low-level language (perhaps because worst-case behaviour is really important or I may want to run in a low-memory device or the DB was a "pure overhead" software that aims to minimise memory consumption that's needed for a co-located resource heavy application).
Then, if this were an actual product that people would depend on for a long time, the obvious choice would be C++, because of its maturity and good prospects. But say this is hypothetical or something more adventurous that allows for more risk, then I would say it entirely depends on the aesthetic preferences of the team, as neither language has some clear intrinsic advantage over the other. Personally, I would prefer Zig, because it more closely aligns with my subjective aesthetic preferences, but others may like different things and prefer Rust. It's just a matter of taste.
> the DB was a "pure overhead" software that aims to minimise memory consumption that's needed for a co-located resource heavy application)
Thanks pron for the reply. This describes it the best. To minimize resource consumption in a "pure overhead" software. It's currently written in Java and we are planning a rewrite in a systems PL.
I would first spend a good amount of time figuring out if you can't just keep it in Java, because it's not just the rewrite in C++ that's expensive, but a low-level language would make maintenance and evolution costlier forever.
If memory footprint is the issue, I would recommend watching this: https://youtu.be/mLNFVNXbw7I. A lot of people misunderstand memory consumption, and even in Java there are many options to try. There could definitely still be situations where a low-level language is the only choice, but it's not a decision to be taken lightly.
Then, if this were an actual product that people would depend on for a long time, the obvious choice would be C++, because of its maturity and good prospects. But say this is hypothetical or something more adventurous that allows for more risk, then I would say it entirely depends on the aesthetic preferences of the team, as neither language has some clear intrinsic advantage over the other. Personally, I would prefer Zig, because it more closely aligns with my subjective aesthetic preferences, but others may like different things and prefer Rust. It's just a matter of taste.