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CloudMonkey Member
Member

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

1 ACCEPTED SOLUTION

Accepted Solutions
Microsoft v-danhe-msft
Microsoft

Re: Very slow transformation

Hi @CloudMonkey ,

The performance for your data model is related on many aspects, you could refer to below link:

https://www.thebiccountant.com/2017/05/29/performance-tip-partition-tables-crossjoins-possible-power...

Below link explains how you can use a process monitor to find out how much data Power Query reads from a file:

https://blog.crossjoin.co.uk/2018/07/19/using-process-monitor-to-find-out-how-much-data-power-query-...

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

Community Support Team _ Daniel He
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

View solution in original post

2 REPLIES 2
Microsoft v-danhe-msft
Microsoft

Re: Very slow transformation

Hi @CloudMonkey ,

The performance for your data model is related on many aspects, you could refer to below link:

https://www.thebiccountant.com/2017/05/29/performance-tip-partition-tables-crossjoins-possible-power...

Below link explains how you can use a process monitor to find out how much data Power Query reads from a file:

https://blog.crossjoin.co.uk/2018/07/19/using-process-monitor-to-find-out-how-much-data-power-query-...

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

Community Support Team _ Daniel He
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

View solution in original post

Microsoft v-danhe-msft
Microsoft

Re: Very slow transformation

Hi @CloudMonkey ,

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

Community Support Team _ Daniel He
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

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