My Oracle Support Banner

Insert Into Remote Table Using DBLINK Over VPN Tunnel or Firewall Hangs on Large Number of Rows (Doc ID 742535.1)

Last updated on FEBRUARY 19, 2019

Applies to:

Oracle Net Services - Version to [Release 9.2 to 12.2]
Information in this document applies to any platform.


Suddenly an INSERT (as) SELECT FROM DBLINK hangs with source database waiting on "SQL*Net more data from dblink" wait event and the remote (target) shadow process disappearing.

This also hangs indefinitely with source in "SQL*Net more data from dblink" wait event.

A PL/SQL doing an explicit cursor just fetching (not inserting) fails after 20 or so rows.

The only thing that runs to completion is plain SELECT from Sqlplus.


Database Links to databases on Local Area Network (LAN) do not exhibit this problem.  This issue is limited to a database link where the target is a remote database accessed via a VPN Tunnel using default port 1521.


To view full details, sign in with your My Oracle Support account.

Don't have a My Oracle Support account? Click to get started!

In this Document

My Oracle Support provides customers with access to over a million knowledge articles and a vibrant support community of peers and Oracle experts.