How to shortage the retrieving / loading data time to append new data to the existing results

[NilsLam]

I used "From Folder" options to create a query with several transformations, this folder contains the daily data files and the new generated file will be kept saved on this folder every single day.

Just like the subject said that how to shortage the retrieving / loading data time to append new data to the existing results. Many thanks.

[edhans · Accepted solution]

You cannot do that. What you want is Incremental Refresh, but that only works with relational database systems like SQL Server. It will not work with files. You can have 1,000 files in a folder that are a year old and add one file today, and Power Query will go through all 1,001 files again on the next refresh.

[ahmedoye]

@NilsLam , I have two things i'll recommend to you.

1. Open your PBIX, go to File>>Options>>Current File>>Data Load. Uncheck the box for "Allow data preview to load in the background?
2. In Power Query, go to your applied steps area and be sure all steps are necessary.
   Chief amogst what you look out for is steps that are "Changed Type" which are usually applied by default after some certain steps. You want to typically have only one "Changed Type" step at the end of your steps.
   Another Chief to look out for is "Renamed Column" steps. You can typically just edit the "M" code in the formula bar that in steps that generate default names for columns.
   
   If this answers your question, kindly mark it as a solution.

[NilsLam]

@ahmedoye 

Thanks for your comments, I thought my problem is too large data size and too many data transformation setting that prolongs the retrieving time, so my concern is how kept the existing results and just transformed the new data then append.