Power Query Editor REALLY SLOW - SQL SERVER CONNECTION

[Anonymous]

Hello Commnuity. I'm building a data model connecting to a SQL Server dataset. I've performed a lot of steps into the query, merged table, appeneded queries....but now, whenever I open the query editor, it takes forever to load the data so I can keep performing the necessary modifications.  The data model keeps loading and loading...and also, if a perform any changes, it will take a lot of time to load.

Please HELP!

[Anonymous · Accepted solution]

Hi @Anonymous ,

Which connection mode you are using to connect SQL Server? Import or Direct Query? Is the underlying database running smoothly? It is difficult to give a suitable solution without sample data and related execution operations. Because there are many possible reasons(large amount of data, specific applied steps etc.)... You can try the following operations anyway and see if the situation has improved later:
1. Upgrade your Power BI Desktop to the latest version
2. Uncheck background data (File –> Options –>Data Load –>Allow data previews to download in the background)

Any way to speed up really slow refresh times in Power Query?

3. Refer the following blog to update/optimize the report

Optimizing the data model

Transformations in Power Query - Very Slow Performance

Best Regards

[Sydney_Cider]

For those that still find this difficult to navigate, you may be doing this in Power Query from Analysis Services.

 - Added Items to a query then filtered query.

I did and a clever soul in my organisation found this solution to stop us maxing SQL server resources which made queries run for up to an hour for relatively simple requests.

The issue with this can be the complexity and the size of the data warehouse that you are querying.  The issue

 occurs at the added items step where the query is building the relationships within a large dataset when you request fields from different tables.

Our solution is to use MDX as the first step. For those that can't build these natively and that includes me, install SQL Server Management Studio and browse to the Analysis Services cube. You can then drag and drop the fields you want to use as well as filter at this step in a manner similar to pivot tables in Excel so very user friendly.

Once you have this code from SSMS which you can get in Design Mode, launch Power Query and follow the steps below.

- Alt + F12 to launch power query editor.

- New Source | Database | Analysis Services

- Server is your server address, Database is your Analysis Server model name and MDX or DAX query is the code you generated in SSMS.

We're finding the time difference is in the thousands of percent better by comparison.

[Anonymous]

Hello My Friend. Thanks for the reply. I'm using a EXCEL file as datasource...2 files one with many tabs (65MB) and another one with few more tabs (20MB). I'm appending the tabs together, to merge them in one single table within power query. I've already tried to disable that "Allow data preview to download in the background" and it doesn t let me see the data or manipulate it.

Thanks again.

[Anonymous]

Hi @Anonymous ,

According to your description, it seems that there are multiple queries in your original model, and finally you integrate them into a single table through append and merge operations in Power Query Editor. Could you please perform the following operations in your source excel file before connecting the excel file with Power BI:
1. Remove unnecessary columns
2. Can the append and merge operations you perform in power query be completed in excel in advance?

Best Regards