topic Re: Performance issue with AVERAGEX in DAX Commands and Tips

Performance issue with AVERAGEX

JustinDoh1 — Tue, 28 Jan 2025 23:58:28 GMT

I have a about 1.1 million rows of data with 7 columns.

I tried this measure called "Average" to filter my visual, PBI visual is having a big performance/memory issue.

Below is detail of that measure that is causing performance issue:

Average = AVERAGEX
(

VALUES(DimDate[DateFormat]),

CALCULATE(

[ClientD_M1]

)

When I tried on the visual as 'Average is not 0', the visual is having a performance issue:

Bottom is detail of a measure called [ClientD_M1]:

ClientD_M1 = count('TblCensus'[ClientID]) + 0

Is there any better way to optimize the DAX of "Average" by chance?

Or is there any way to apply the filter (value that is greater than 0) in other possibly way?

Thanks.

Re: Performance issue with AVERAGEX

Anonymous — Wed, 29 Jan 2025 05:29:30 GMT

Hi JustinDoh1 ,

The AVERAGEX function combined with VALUES may cause performance issues because of the excessive number of rows and context transitions it creates. If you can simplify the context in which AVERAGEX operates, it might help. You can try using the following DAX:

Average = AVERAGEX( ALLSELECTED(DimDate[DateFormat]), [ClientD_M1] )

If possible, pre-aggregate data in Power Query or in the data source to reduce the number of rows processed in DAX and reduce context switching.

Another approach is to use SUMMARIZE to create a table with the precomputed values, and then use AVERAGEX on that summary table.

Average = VAR SummarizedTable = SUMMARIZE( 'TblCensus', 'TblCensus'[DateFormat], "ClientCount", COUNT('TblCensus'[ClientID]) ) RETURN AVERAGEX( SummarizedTable, [ClientCount] )

Hope this will help you!

Best Regards,
Dino Tao
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

Re: Performance issue with AVERAGEX

bhanu_gautam — Wed, 29 Jan 2025 05:31:02 GMT

JustinDoh1 Instead of using VALUES, you can use SUMMARIZE to create a summarized table that might perform better.

Average =
AVERAGEX(
FILTER(
SUMMARIZE(
'TblCensus',
DimDate[DateFormat],
"ClientD_M1", [ClientD_M1]
),
[ClientD_M1] > 0
),
[ClientD_M1]
)

Re: Performance issue with AVERAGEX

JustinDoh1 — Wed, 29 Jan 2025 23:01:59 GMT

Anonymous Thank you for your help. I think applying additional filter later to the visual would still slow down the performance so I chose "bhanu_gautam"'s soltuion. I have a question. You mentioned about "pre-aggregate data in Power Query". How do I go about doing this?

Re: Performance issue with AVERAGEX

Anonymous — Thu, 30 Jan 2025 00:47:26 GMT

Hi JustinDoh1 ,

For example, you can group your data in Power Query to reduce the amount of data you need to process and complete some calculations in advance. This is just one of the ways to aggregate data in Power Query, and you can explore other methods on your own.
How to GROUP BY or summarize rows - Power Query | Microsoft Learn

Best Regards,
Dino Tao

Re: Performance issue with AVERAGEX

JustinDoh1 — Thu, 30 Jan 2025 01:38:50 GMT

Anonymous Regards to my case where I need to filter by "Average" is not 0, how do I group by? "Average" is a measure. Would Power Query work with a measure, not just column? Thanks.

Re: Performance issue with AVERAGEX

JustinDoh1 — Thu, 30 Jan 2025 02:10:49 GMT

bhanu_gautam I have a question. I am experimeting with performance. It appears that when I try the same query in Bookmark, it is really slow or even it crashes. It says "There's not enough memory to complete this operation." Why is that?