Retrieve data from Hive /Query Ran 7 times before load the data

[GeorgeKarl]

I tried to load data into Power BI Desktop through ODBC connector into Hive .

I ran this query Select distinct User_id,Latitude,longitude,timestamp from position where ds='2024-08-27'.

The data engineer of Hive told that the query run 7 times (logs) .

The data are partinioned per ds .

I am wondering for which reason ran the query 7 times .

At the same time from same Power BI ,one query retrieve data from SQL Server and ran once the query .

Could anyone knows why BI ran repeatedly  the query?

[Anonymous]

Hi @GeorgeKarl 

Power BI sometimes runs queries multiple times for a variety of reasons. There are several potential causes for a query to run multiple times:

Metadata retrieval: Power BI may query the data source several times to retrieve metadata about tables and columns.

Data preview: When data is loaded, Power BI typically runs queries to generate data previews.

Caching: Power BI may cache results to improve performance, which may cause the same lookup to be executed multiple times.

Query folding: If you use transformations in Power Query, Power BI may collapse those transformations back to the source, resulting in multiple executions.

Background refresh: Power BI may refresh data in the background, especially if you set up a scheduled refresh.

In contrast, a SQL Server query may only run once because it may not require the same level of metadata retrieval or caching, or Power BI may optimize it differently.

Regards,

Nono Chen

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