Kusto/Azure Data Explorer Client Query Limits

tessaw · ‎05-05-2020

Hi all,

My team is using Kusto/Azure Data Explorer for our PowerBI dashboards. We recently ran into some query limit errors. After some investigating, we found this page of documentation:
https://docs.microsoft.com/en-us/azure/data-explorer/kusto/concepts/querylimits
Setting our truncationmaxsize to a large amount, like 90000000, in our query seems to be working for now. What we're curious about is this line in the article:

While you can increase the limit without bounds, eventually you'll reach client limits which are currently not configurable.

This implies that there is a limit coming from the PowerBI side since it is a client of our query? Is there a way we can find the truncationmaxsize and truncationmaxrecords limits from the PowerBI side?

Thanks in advance,
Tessa

v-lionel-msft · ‎05-06-2020

Hi @tessaw ,

What is the error message?

What connection mode have you adopted? Import or Direct Query?

It may be an error caused by a limitation in Power BI.

Best regards,
Lionel Chen

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

tessaw · ‎05-06-2020

Hi @v-lionel-msft , the actual error in PowerBI itself was not very descriptive, it only said that some of the rows failed to refresh/load. Only once I ran the query in Kusto/Azure Data Explorer itself did I get a descriptive error message which led me to the article I listed in the original post. Specifically, the error message was:
"The Kusto DataEngine has failed to execute a query: 'Query result set has exceeded the internal data size limit 67108864 (E_QUERY_RESULT_SET_TOO_LARGE).'"