[keycloak-user] DataBase connectivity requirements

Hi. Recently we were trying to move Keycloak storage from H2 to Oracle on our test environment and faced some troubles. Our test DB instance is situated in different office and is available over VPN connection with ping about 200-400 ms. We made some preliminary actions (create schema, populate it with keycloak-update.sql ...). So during startup everything was ok except quite long db data initiation (master realm etc.). I successfully logged as master realm admin. UI works with little freezes. The problem was when i tried to create new realm. Page in browser was showing loading, then UI showed timeout-error popup. Few seconds later i tried to create new realm again and then got Exception in logs (something related to "transaction was rolled back"). Seems that thats all because of ping delays during DB requests. "New REALM operation" is not single composite DB request but is sequence of small requests created by Hibernate. Am i right? So the question is: Is there any strong requirements on DB connectivity for Keycloak? Or maybe we can do some customization for adopting to this case?