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Append vs Union to improve data load

I'm looking to a workaround to avoid long-lasting data refresh and I'm testing two scenarios and It seems working with DAX has a better result than query editor.

 

In the model there are two table 
- table A (fresh data) of 10MB resh 
- table B (historical data) of 100MB (“enable load”turned off)

 

Scenario1)
Using APPEND in query editor. Every refresh take a lot of time and Power BI load 100MB

Scenario2)
Using DAX function UNION to create an additional table. Refresh is fast and load only 10MB of data

 

Why APPEND load so much data even if the biggest table is not refreshed?

Any other consideration observation?

 

regards

Status: New
Comments
v-qiuyu-msft
Community Support

Hi @marcodea,

 

Scenario1) Do you append data from table B to the table A? 

 

Based on my research, the query editor cannot read the data stored in the data model. Even if it could, the data in the data model represents the output of the very last step and the query editor wants to be able to show partial output for intermediate steps. That data is never loaded into the data model. In your scenario, as the Table B has "enable load" turned off. Query Editor should read the data from data source then append this data to Table A. 

 

Scenario2) Do you mean use Union() function for Table A and Table B? As I tested, if the Table B has "enable load" turned off, data of Table B isn't loaded to the data model, it's not able to refrence the Table B in Union function. 

 

Best Regards,
Qiuyun Yu 

marcodea
Helper II

Hi v-qiuyu-msft , thanks for your reply.

 

I did a mistake in my previous message. I turned off INCLUDE IN REPORT REFRESH whereas ENABLE LOAD is still active.

 

Regards