I am going to change some parameters on primary database (db cache, java pool etc.). I am not sure, if the changes are automaticallly propagated to standby or if I have to make the changes manually on stanby site too? I couldn't find clear answer in documentation. Can you explain please how parameter changes work in dg physical configuration?
if you do some alter system set command on your primary only this database will be changed. You have to do the some changes on your standby. Becuase this changes are made in the spfile and not in the redo stream they will not be send to the standby.