Impala and Power Query

[robarivas]

Just recently used the Impala connector (import mode) for the first time. What I noticed is that there is no "View Native Query" selectable in the Applied Steps. So how do I know if Query Folding is working or not? Does the Query Folding concept somehow not apply to Impala? If not, is there any chance that a Power Query query could run inefficiently on the Impala database/server side? Do IT people need not fear Power Query queries for some reason? And how would I mitigate that? Just trying to understand so I don't cause any kind of issue. Wouldn't want lose access or be told I can't use Power Query anymore.

[v-frfei-msft · Accepted solution]

Hi @robarivas ,

Generally, if custom SQL queries cannot be run against the source, the Native Query function is not available. Other sources which do not have a Native Query option include: text files, streaming and other online sources, and most data sources in beta. Additionally, if no "SQL" version of a function or transformation is readily available, generally, the Native Query function will be disabled at that point. Unfortunately, I have been unable to discover a reliable source for the list of functions, sources, and transformations which disable Native Query display (and Query Folding).  Even so, the availability of this tool is a giant step forward in producing efficient Power BI data sources and troubleshooting both performance and other issues with data sets in Power BI.