Forum Discussion
Very slow transformation
Hi,
I have a transformation that is very fast in query editor (when I click on each of the steps in turn), but extremely slow (runs for more than an hour) when I "close and apply". Please do you know of any general reasons why this may happen? (I'm just connecting to a excel worksheet, transposing and filtering)
Thanks,
CM
Hi Anonymous ,
The performance for your data model is related on many aspects, you could refer to below link:
Below link explains how you can use a process monitor to find out how much data Power Query reads from a file:
Below link has some information about how Power Query caches data, which is particularly important if you have queries referencing other queries:
https://blog.crossjoin.co.uk/2016/11/20/referenced-queries-and-caching-in-power-bi-and-power-query/
Also if you don't need to preview all of the queries you can turn off Background Data; go to Query Options > Data Load > deselect 'Allow data preview to download in the background'.
Hope it could help you.
Regards,
Daniel He
2 Replies
v-danhe-msftMicrosoft Employee
Hi Anonymous ,
The performance for your data model is related on many aspects, you could refer to below link:
Below link explains how you can use a process monitor to find out how much data Power Query reads from a file:
Below link has some information about how Power Query caches data, which is particularly important if you have queries referencing other queries:
https://blog.crossjoin.co.uk/2016/11/20/referenced-queries-and-caching-in-power-bi-and-power-query/
Also if you don't need to preview all of the queries you can turn off Background Data; go to Query Options > Data Load > deselect 'Allow data preview to download in the background'.
Hope it could help you.
Regards,
Daniel He
- v-danhe-msft
Hi Anonymous ,
Could you please tell me if your problem has been solved? If it is, could you please mark the helpful replies as Answered to close this topic?
Regards,
Daniel He