ORA-03135 connection lost contact First i connect to oracle remotely, then open pl/sqldeveloper create one table. Then i am trying to import csv file to PL/sql developer. Importing process starts normally, but every day midnight we face 


  ORA-03135 connection lost contact. 


The file is almost 3 GB containing 20 million records.

the importing process stop after 10 million records.
I think check your network connection.
In between your network connection interrupted.
So In your sqlnet.ora and also on sqlnet.ora on your server try to change inbound connection or outbound connection and also try to set connection timeout parameter in sqlnet.ora file.