I think I'll have to wait until HikariCP supports virtual threads:

My reading of that (long) thread is that Hikari doesn't use synchronized on any critical path so it "doesn't matter". What is a real issue is vthread code overwhelming the connection pool and getting timeouts - which is already a problem with native thread code, but perhaps more likely with vthread code.

No one provided a repro case of pinning within Hikari...

Interesting. There are other discussions in the issues tab that talk about it. However, worth a shot I think! I'm happy for the connector change too! 🙂

Databases have a limit on concurrent connections so you can't have unlimited pool sizes anyway - so there has to be some throttling somewhere.