I have two schemas A and B within one database. I have private synonyms in schema B for all the tables in schema A. I have procedure in schema B which creates the Materialized view with full referesh. This materialized view uses these private synonyms. It has five queries with union. When I execute this procedure in schema B, it just hangs. Also, my DBA does not see any activity on database level. When the DBA runs it on the server, his session also hangs. When I run these queries individually, it works fine.