You can achieve this by just putting a new schema file in the __protobuf_metadata cache, exactly the same way you did it first time . No need for restart. Just make sure the new schema follows good schema evolution principles to ensure backwards compatibility. If you marked previously non-indexed fields to be indeed then do not forget to start a mass indexing operation to reindex the content or your old content will not be searchable using those fields.
What Infinispan version are you using? I'm asking because there were some bugs in the area of protobuf schema persistence that might impact you.
I am using the latest 9.0.1 file. How to add the file into
__protobuf_metadata cache? Which version is stable to get going>
9.0.1 should work fine. For remote query with protobuf please have a look at this quickstart guide: jboss-jdg-quickstarts/remote-query at jdg-7.1.x · jboss-developer/jboss-jdg-quickstarts · GitHub
Registering a protofile is done with just a simple put operation in the __protobuf_metadata cache, see here: jboss-jdg-quickstarts/AddressBookManager.java at jdg-7.1.x · jboss-developer/jboss-jdg-quickstarts · GitHub