[rickkjp]

Not a weakness so much I guess, just a different cost/performance trade-off choice that I think largely was a direct result of having been written in java for enterprise purposes at a time when Rust didn't yet exist. "Low memory" and "written in Java" are at least in my experience not terribly compatible goals.

[FrustratedMonky]

I don't think it is completely about the language. JVM taking more memory isn't the problem with in-memory databases. It is having more data than can fit in memory. Even an in-memory SQL Db would eventually run out of memory, no matter the language it was coded in.

A lot of DB design is around this subject. And so it seems like if you found a way to allow a graph DB data to expand beyond in-memory by allowing it to reside on disk is a really big deal. But, since it would be a big deal, I'd think the big guys with a lot of resources would offer it as an option, or feature. It would be worth investing in.