Today we have been reported this error, if you execute “oerr ora 2020” command at unix prompt you can see the solution proposed By Oracle;
// * Action: Increase the open_links limit, or free up some open links by
// Committing or rolling back the transaction and canceling open
// Cursors That reference remote databases.
Normally, these problems are the management of database links, you must to close them explicity . The command is;
alter session close database link <DBLINK-NAME>
After running the command, usually need to close the transaction (commit or rollback). On the other hand when performed commit or rollback in the session that has opened a database link, remains the session, but closes when it opens another database link.
One more thing, to see the database links opened you can use the next statement.
SELECT db_link, in_transaction FROM v$dblink
HTH – Antonio NAVARRO