Skip to main content
cancel
Showing results for 
Search instead for 
Did you mean: 

The Power BI Data Visualization World Championships is back! Get ahead of the game and start preparing now! Learn more

Reply
filiparibeiro
Helper III
Helper III

Power Query Speed - File Source Type

Hello.

Do queries run faster when the source is a local excel file instead of sharepoint excel files? If so why does this happen and is there a way to make it faster? Would table.buffer help?

Thanks in advance. 

1 ACCEPTED SOLUTION
MatthRichardsUK
Resolver I
Resolver I

It is generally faster to work with data from a local Excel file rather than from a file stored on SharePoint, because the data does not need to be transferred over the network. The speed difference will depend on the size and complexity of the data, as well as the network connection between your computer and the SharePoint server.

Using the Table.Buffer function in Power Query can improve the performance of your queries by loading the data into memory, which can be faster than reading the data from the source each time it is needed. However, this may not always result in a significant improvement in performance, especially if the data is large or the query is already running efficiently.

There are a few ways you can try to improve the performance of queries that retrieve data from SharePoint:

  1. Make sure the network connection between your computer and the SharePoint server is fast and stable.
  2. If the data is large, try to optimize the queries to only retrieve the data that is needed, rather than loading the entire dataset into memory.
  3. Consider using the Table.Buffer function to load the data into memory.
  4. If the data is being used frequently, consider creating a local copy of the data and using that copy as the source for your queries. This can be done using Power Query's "Append" or "Merge" functions to combine the data from the SharePoint file with the local copy.

View solution in original post

1 REPLY 1
MatthRichardsUK
Resolver I
Resolver I

It is generally faster to work with data from a local Excel file rather than from a file stored on SharePoint, because the data does not need to be transferred over the network. The speed difference will depend on the size and complexity of the data, as well as the network connection between your computer and the SharePoint server.

Using the Table.Buffer function in Power Query can improve the performance of your queries by loading the data into memory, which can be faster than reading the data from the source each time it is needed. However, this may not always result in a significant improvement in performance, especially if the data is large or the query is already running efficiently.

There are a few ways you can try to improve the performance of queries that retrieve data from SharePoint:

  1. Make sure the network connection between your computer and the SharePoint server is fast and stable.
  2. If the data is large, try to optimize the queries to only retrieve the data that is needed, rather than loading the entire dataset into memory.
  3. Consider using the Table.Buffer function to load the data into memory.
  4. If the data is being used frequently, consider creating a local copy of the data and using that copy as the source for your queries. This can be done using Power Query's "Append" or "Merge" functions to combine the data from the SharePoint file with the local copy.

Helpful resources

Announcements
Power BI DataViz World Championships

Power BI Dataviz World Championships

The Power BI Data Visualization World Championships is back! Get ahead of the game and start preparing now!

December 2025 Power BI Update Carousel

Power BI Monthly Update - December 2025

Check out the December 2025 Power BI Holiday Recap!

FabCon Atlanta 2026 carousel

FabCon Atlanta 2026

Join us at FabCon Atlanta, March 16-20, for the ultimate Fabric, Power BI, AI and SQL community-led event. Save $200 with code FABCOMM.

Top Solution Authors