[keycloak-user] DataBase connectivity requirements

[Ilya Korol]

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?