<@U319ZJ3B4> I've got a Kotlin + VertX web project...

# exposed

[janvladimirmostert]

@sss I've got a Kotlin + VertX web project in production, it took a bit getting used to (mostly since I had to translate the Java docs to Kotlin code), but it's very nice otherwise.

I've looked at VertX JDBC, but it's about as minimalist as using straight JDBC, so it's missing a lot of things that you get out of the box with Hibernate.
It does have a threadpool via C3P0 which is awesome.

Since Hibernate is a blocking library, you either need to use VertX Web with a blocking handler which will negate the performance benefit you're getting with using VertX Web in the first place
(which is what I've been doing for the last project as a quick fix to get around DB blocking the event loop - performance was not an issue there, three people are using the system)
or you need to use Quasars via VertX Sync in order to still use async VertX and not block the event loop (something I'm busy experimenting with for a project that does require good performance)

Regarding your hibernate question, I'm using a connection pool, Hibernate comes stock standard with a connection pool, busy replacing it with C3P0

If you're using VertX with Spring in Kotlin and setting up Hibernate via Spring, Spring will force you to setup a DataSource for Hibernate - the basic datasource that most examples are using will open and close a connection per transaction.
It's fairly easy to replace that datasource with a C3P0 connection pool as well. I've decided to abandon Spring when using VertX since it increases startup time due to Spring's annotation scanning.
Cutting Spring out will require you to also find a replacement for Spring @Transactional, can be done by writing your own transaction block which will start a transaction via the entity manager and then commit it at the end of the transaction.