FAQ

Q: I am getting strange transaction isolation behavior after changing it, what is happening?

A: Always use the JDBC Connection.setTransactionIsolation() method rather than executing SQL to change the isolation level. HikariCP must reset the isolation level for connections returned to the pool, but only does so if it detects that the isolation level has changed. Using SQL rather than the JDBC API to manipulate the isolation level prevents HikariCP from being able to detect the change, and therefore it will not reset the isolation level.