Insert into table through dblink very slow after upgrade database to 11.2.0.4

Hi all!

After I upgrade the database from 11.2.0.1. to 11.2.0.4, I have become very slow query through dblink, who previously worked quickly, the maximum per minute. I'm trying to insert into a local table from a remote database via dblink. While running query, i see event "sql*net message from dblink" with expectations that can hang very long. I tried to gather stats on both databases, gathered statistics on the full database, data dictionary and fixed objects, but nothing helped. However, if I do CREATE TABLE AS SELECT * FROM tables@dblink, then all too quickly works. What could happen