Intermittent ORA-03135 Error in Power BI Gateway Connection to Oracle Database

[abhi21pura]

Hi All,

We have been facing ORA 03135 intermittently since 3 months while running PowerBI refreshes in all of our environments (the frequency of this error is 4 in 10 PBI refreshes), below are the details  

Source: Oracle database hosted on RHEL8 VM on Azure
Gateway: On-Premises Data Gateway (Windows VM on Azure)
Workspace: Power BI Premium Capacity
Firewall: Exists between on-premises gateway and Oracle database
Issue: Intermittent ORA-03135 error (Connection lost contact)
Gateway Version: July 2024 (3000.230.13)
Oracle Client for MS tools installed on Gateway Server: 19.21

Additional Context:

• Other applications connecting through the firewall to the same database and developers connecting from their Laptops/VMs do not experience the ORA-03135 error, even with idle connections for 10-12 hours.
• This suggests that the firewall is not terminating idle connections.

Things We Have Tried:

On the Oracle Database:

• Set SQLNet.Expire_Time = 1 min
• Set SQLNet.Expire_Time = 10 mins
• Set DCD = True

Power BI Gateway Connection String (TNSNAMES.ORA):

• Added Enable_Broken = True
• Added Connection Pooling = False
• Added Validate Connection = True

None of the above solutions have resolved the issue. Any further insights or suggestions from the community would be greatly appreciated!

Adding my colleague @SureshBalireddi for further visibility.

[abhi21pura]

Hi Jianpeng,

Thank you for the response, We do not think that this is a firewall or a network issue as we have seen this error within 10 seconds as well.

We are not able to replicate this issue as it happens randomly.

We are using Dataflow Gen1, and Oracle being our datasource, is dataflow not able to handle the volume of data?
I have seen someone else facing this issue and asking this question on other forum but there is no solution posted to it.

https://community.fabric.microsoft.com/t5/Dataflow/MashupException-Error-Oracle-ORA-03135-connection... 

[Anonymous]

Hi, @abhi21pura 

ORA-03135 may occur for a number of reasons, including network devices, operating systems, databases, and most likely due to network flashbands and firewall configurations.

This issue is caused by the firewall if the persistent connection setting is not enabled.

Under normal circumstances, if the interval between two consecutive packets of a TCP session arrives at the firewall is greater than the retention time of the session, the firewall deletes the session information from the session table to ensure network security. After the subsequent packets arrive at the firewall, the firewall discards the packets based on its forwarding mechanism, causing the connection to be interrupted.

ORA-03135 - Database Error Messages

Oracle.DataAccess.Client.OracleException ORA-03135: connecti... - Ask TOM

Coordinate with your network engineer to resolve the firewall issue.

Best Regards

Jianpeng Li

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.