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Snapshot fails due to __NULL_DB_UNIQUE_NAME__ (KBA5172)




KBA# 5172


When attempting to perform a Snapshot of an Oracle dSource, the following fault may be raised by the Delphix Engine:

Bundle ID fault.policy.dsource.policy.connect.failed
Title Unable to connect to remote database during dSource policy enforcement
Action Make sure that the affected database is running and connectivity is available.
Description Unable to connect to database "MYDATABASENAME" via JDBC. The database or host may be down. Connection error: Environment monitor expected to connect to database "MY_DB_UNIQUE_NAME" but found database "__NULL_DB_UNIQUE_NAME__" instead.
Response dSource snapshot policy is disabled.


Applicable Delphix Versions

This article applies to all available versions of the Delphix Engine.


This issue may occur when the source Oracle instance does not provide complete database information in its v$database view.

The Delphix Engine requires this information to be accurately reported by the Oracle instance, to ensure that we have reached the correct Oracle database after connecting to an Oracle listener.

To resolve this issue, it may be necessary to restart the source database (stop/start or startup force).


The information provided by Oracle in its v$database view may become incorrect after certain database changes, such as re-creation of the controlfile.

This behavior is outside the control of Delphix, and we depend on the accuracy of the information reported by Oracle to ensure that we are taking snapshots of the correct source database.

To confirm that the db_unique_name is not being correctly reported, please connect to your source database and execute the following query:

select db_unique_name from v$database;

An empty result set indicates that Oracle is not correctly reporting the database's unique name.


If it is not feasible to restart the Source database, please contact your database administrators or database vendor to troubleshoot this behavior further.