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Could not connect to database: NET: Invalid SID



Hello, I have Oracle RAC Cluster and I'm trying to query it using PRTG. I would like to test connectivity to the Oracle database using PRTG Oracle SQL Sensor. The SQL Expression: select count(*) from sys.v_$session. The Connection mode: Use Direct Mode (TCP/IP) For direct mode I using the service name as defined in "tnsnames.ora".

The error that I get: Could not connect to database: NET: Invalid SID

As far as I know the connection method to RAC DB is through service and no SID.

Please advise.

Thanks, Yaron

database oracle use-direct-mode

Created on Feb 6, 2014 3:10:33 PM

1 Reply




thank you very much for your KB-Post. It is important to notice that PRTG exclusively uses the Direct Mode as regards Oracle sensors.

The following provides a comparison of the Direct Mode and the OCI Mode:

Applications compiled with and without Direct mode have similar size and performance. Security of using Direct mode doesn't differ from using OCI without Oracle Advanced Security. dotConnect for Oracle uses DES authentication and now does not support Oracle Advanced Security in Direct mode.

The advantages of Direct mode are:

  • installation and administration of Oracle Client software is not required;
  • system requirements are reduced.

Direct mode has some limitations:

  • Connect using TCP/IP protocol only.
  • Oracle RAC (Real Application Clusters) is not supported.
  • OracleLoader class is not available

Please note that we don't guarantee dotConnect for Oracle compatibility in Direct mode with all Oracle servers and in every network. We have tested it with all versions of Oracle server for Windows and Linux since 7.3 in local network.

Other platforms may cause some incompatibility issues.

  • Direct mode does not support NLS conversion on client side.
  • Transparent Application Failover not supported
  • Statement caching is not available.
  • OS authentication, proxy authentication, and changing expired passwords features are not available.

At the moment, PRTG can only monitor against a single instance, not against a clustered service. Sorry.

best regards.

Created on Feb 7, 2014 1:10:53 PM by  Torsten Lindner [Paessler Support]

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.