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title: "Discussion on \"Did your Oracle data refreshes slow down after the June 2026 Power BI on-prem gateway update? Here is what happened.\" | Hashnode"
description: "Discussion on \"Did your Oracle data refreshes slow down after the June 2026 Power BI on-prem gateway update? Here is what happened.\". The June 2026 on-premises data gateway release broke a lot of Oracle connections, and people noticed within a day. The release announcement collected dozens of comments about it: ORA-12154 alias resol"
url: "https://hashnode.com/posts/did-your-oracle-data-refreshes-slow-down-after-the-june-2026-power-bi-on-prem-gateway-update-here-is-what-happened/6a81cb4b223d73f215cc6b9c"
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# [Did your Oracle data refreshes slow down after the June 2026 Power BI on-prem gateway update? Here is what happened.](https://lukeweaves.hashnode.dev/did-your-oracle-data-refreshes-slow-down-after-the-june-2026-power-bi-on-prem-gateway-update-here-is-what-happened?utm_source=hashnode&utm_medium=feed)

The June 2026 on-premises data gateway release broke a lot of Oracle connections, and people noticed within a day. The release announcement collected dozens of comments about it: ORA-12154 alias resol

Aug 16 · 17 min read · lukeweaves.hashnode.dev  
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## Written by

[Lukas Novacek](https://hashnode.com/@lukeweaves)

@lukeweaves · Prague

  
[View profile](https://hashnode.com/@lukeweaves)

Power BI and Fabric at enterprise scale - the things the docs don't tell you.

BI infrastructure engineer based in Prague. I work on Power BI and Microsoft Fabric at enterprise scale - gateway operations, metadata scanning, and the governance problems that only appear once an estate gets large. I write about the things the documentation leaves out.

## Responses 1

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[Arturo Gonzalez](https://hashnode.com/@arturogf)

[Oct 15](https://hashnode.com/posts/did-your-oracle-data-refreshes-slow-down-after-the-june-2026-power-bi-on-prem-gateway-update-here-is-what-happened/6a81cb4b223d73f215cc6b9c/comment/6ad08e508560be388e31df2d)

Even when setting MashupFlight\_DisableOracleBundledOdacProviderV2 value to True, the problem exists.

FetchSize in: Computer\\HKEY\_LOCAL\_MACHINE\\SOFTWARE\\ORACLE\\ODP.NET\\4.122.19.1

(that is the unmanaged driver section)

reads 131072 on a August 2026 data gateway installed from scratch.

By changing it to 8388608, a small dataset refresh time went from almost 2 minutes to 25 secs.

I am guessing that this setting is set by the OCMT oracle client tool installation and not the gateway? No idea, but anyway it needs to be changed...