I've noticed with that latest version of UNIFYBroker v5.3 above that the Entity Search is slow for large partitions (both connectors and adapters that are usually around 300k-400k entities and about 20 or so attributes each record).
I am aware that some changes have been made to the entity search in recent versions and have raised tickets before about timeout that occur in some cases. I have noticed this occurring in both IIS and self hosted versions. The workaround for this currently is to increase the timeout value, but even when this is increase for larger connectors you can be waiting for 15~20 minutes or longer for the entity search to load. In previous versions of Broker (5.0) the old entity search would load the entities with 5~10 seconds.
So I'm proposing that the search doesn't necessarily need to be reverted but investigated as to why it take so long and to see if it can be improved. Let me know if you need any information on this, I'm happy to provide any information on environments this is currently affecting.
Customer support service by UserEcho