PostgreSQL receives many identical queries from Power BI

[Anonymous]

Hello, Power BI Community! 

Could please someone explain why PostgreSQL receives several identical queries while refreshing one table in Power BI? The tick "Enable parallel loading of tables" is unchecked, it is just one table sending many queries to the database.

This enourmously increases the server loads and can lead to a server and database breakdown. 

So basically, it's just one table that is refreshed, but it sends many queries. The same happens even in the process of opening the file.

The table consists of 2 appended tables: 1 table - CSV-file, with the data before 2019 and 1 table is directly connected to database. Amount of steps is minimal - 4 or 5 - like changed type or renamed columns. 

This problem exists only with PostgreSQL.

Maybe someone knows how to reduce the load on database? And why this happens?

Thank you

[zoloturu · Accepted solution]

Hi @Anonymous ,

Power BI sends several requests to a source to retrieve some metadata first, then the last one is to get data from a table.

Also, if you have some visuals and you use DirectQuery connection in your report then each visual will send a query to a source during report refresh and at each moment when you interact with visuals and filters.

In order to decrease amount of queries to your server you have 2 options:

1. Switch report to Import mode. It will help you avoid of querying your data by visuals
2. Go to options -> Report settings -> Query reduction. And configure some specific behavior for slicers and filters

Regards,
Ruslan Zolotukhin (zoloturu)
BI Engineer at Akvelon Inc. / Kharkiv Power BI User Group Leader / DAX & Power BI Trainer
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