We have a strange behaviour using Exposed with spring boot and hikari with maximum pool size 1. We use this size of pool in local/test environments, and we get an error:

HikariPool-1 - Connection is not available, request timed out after 30005ms

Quick debugging showed, that Exposed is trying to acquire some metadata about database before transaction started. This is as far as I can get before error: org/jetbrains/exposed/sql/Database.kt:22. Is it an expected behaviour and exposed requires minimum amount of connections when used with spring, or is it something that can be fixed?

Yes, Exposed required a database metadata to load keyword dictionaries and other flags. But it should return the connection to pool. Do you experience the problem with that?

Yes, but that problem occurs only when pool is fixed size and contain only 1 connection