Impact of duplicate table, and calculated table

[Skrnz63]

Hello, i manage big data in a Power BI, and with Power Query, the merges take too long time. So I decided to switch on DAX. But before starting, i wanted to know if a lot of NATURELLEFTOUTERJOIN on big calculated table, duplicate table and other operations with table in DAX can affect the performance of the report. Not the refresh but the report. 

I just started and i figure out that my file went from 180 000 to 330 000 Ko with just a duplication of table and a LEFT JOIN between 2 big table (because the LEFT JOIN in DAX don't want same name of column in both table and i can't change the columns name in original table, so i have to duplicate the table). I'm worried about the performance that my report may take.

What is your opinion and what are your advices ?

[v-jingzhang]

Hi @Skrnz63 

Duplicating a table will create a total copy of the original table. It connects to the same data source and repeats all transformation operations, then imports data into the model. So I think it will double the size of the data. 

I think perhaps you can try merging a table to itself? It has (Current) suffix for itself when selecting the second table. 

Best Regards,
Community Support Team _ Jing
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