Does MashupDefaultCommandTimeout affect Snowflake large-result failures?

Hi everyone,

We are troubleshooting an intermittent Power BI Service refresh issue with Snowflake through an On-premises Data Gateway.

Our architecture is:

Power BI Service → On-premises Data Gateway → Corporate Network/Proxy/Firewall → Snowflake

The issue occurs mainly with large datasets. The Snowflake query completes successfully, but the refresh sometimes fails while retrieving the result data.

The errors include:

An existing connection was forcibly closed by the remote host wsarecv: An existing connection was forcibly closed by the remote host CURLcode=35 SSL connect error Arrow chunk download failed – max retries done

The same report can fail on one refresh and succeed on retry.

We also tested multiple reports simultaneously. In one test, 11 reports were refreshed at the same time: 8 succeeded and 3 failed. The 3 failed reports succeeded after 1–2 retries.

Snowflake Support confirmed that the query itself is completing and that the failure appears to occur while retrieving the large result set from their STAGE/S3 endpoints.

We have also tested Snowflake Connector Implementation 1.0 instead of 2.0, but the same intermittent failures occurred.

My question

Got a suggestion to add the following setting to:

Microsoft.PowerBI.DataMovement.Pipeline.GatewayCore.dll.config

<setting name="MashupDefaultCommandTimeout" serializeAs="String"> <value>1800000</value> </setting>

This sets the timeout to 30 minutes, followed by a Gateway service restart.

Would MashupDefaultCommandTimeout actually affect this type of failure, where the Snowflake query completes successfully but the connection is reset while retrieving/downloading a large result set?

Or does this timeout only apply to the Mashup/command execution phase, meaning it would not help with the subsequent Snowflake/S3 result download?

If it does not apply to the download phase, what Gateway-side setting or diagnostic would you recommend checking for this type of intermittent wsarecv / CURLcode=35 failure?

We are also checking with our Network Team for:

• TLS/SSL inspection
• Proxy/firewall session or idle timeouts
• Concurrent connection limits
• NAT/PAT exhaustion
• Bandwidth throttling

Any guidance from Power BI Gateway/experts on whether the 30-minute Mashup timeout is relevant to this specific scenario would be greatly appreciated.

Thanks!