BigQuery DB Loader timeout in KNIME 5.4.2 behind proxy/Fiddler – works in 4.5.1

Hi all,

I’m trying to upload data to BigQuery using the DB Loader node. To validate the workflow, I read data from the same BigQuery dataset and simply re-upload it. The workflow uses:

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Google BigQuery Connector

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DB Table Selector

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DB Reader

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DB Table Creator

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DB Loader

All nodes except DB Loader work fine. In KNIME 4.5.1, the DB Loader works without problems. In KNIME 5.4.2, the DB Loader fails with a timeout to oauth2.googleapis.com:

ERROR DB Loader            3:25       Execute failed: org.apache.http.conn.ConnectTimeoutException: Connect to oauth2.googleapis.com:443 [oauth2.googleapis.com/108.177.15.95] failed: Connect timed out

We’re behind a corporate proxy and use Fiddler locally. I’ve added the proxy to Fiddler in KNIME’s Network Settings, and I also set the proxy in the JDBC parameters of the Google BigQuery Connector.

Summary:

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Proxy chain: KNIME → Fiddler (local) → internal corporate proxy → Google BigQuery

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The same proxy configuration is used in both versions 5.4.2 and 4.5.1

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DB Table Selector, DB Reader, and DB Table Creator work in both 5.4.2 and 4.5.

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The DB Loader works without problems in KNIME 4.5.1. In KNIME 5.4.2, the DB Loader fails with a timeout.

Questions:

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Did the DB Loader (or BigQuery extension) change its HTTP/OAuth client in 5.4.x and handle proxies differently than other BigQuery nodes?

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Does the DB Loader in 5.4.2 possibly not honor KNIME’s global proxy settings and require extra properties?

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Anyone with a similar Fiddler + upstream corporate proxy setup who has DB Loader working in 5.4.2—any tips?

Environment:

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OS: Windows

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Proxy in KNIME: Manual; http and https; host:localhost; port:8887; auth: No

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Fiddler: HTTPS decryption off

Thanks for any pointers!

Kind regards

Sven