Forum Discussion
Error Visualizing Data from __time column in Druid
Hi padiga-isw , Thank you for reaching out to the Microsoft Community Forum.
Power BI does not expect a SEARCHABLE field in the SQLColumns result, that attribute isn’t part of the standard output. Instead, it uses the SQLColAttribute call with SQL_DESC_SEARCHABLE to determine if a column supports filtering. However, in your case, even though SQLColAttribute returns SEARCHABLE = 3 for __time, Power BI still blocks folding. This means it likely treats the column as reserved or non-searchable during schema discovery, either because of the driver’s internal metadata or due to Power BI recognizing the column name (__time) as special.
The only reliable workaround is to expose a duplicate of __time under a neutral name like event_time, typed as a standard TIMESTAMP and not flagged internally as special. That column avoids reserved-name logic and will allow filters to fold properly. If you're maintaining the driver, the long-term fix is to make sure the __time column is not treated as special or non-searchable in the driver’s schema metadata, not just at runtime.
Hi padiga-isw , Thank you for reaching out to the Microsoft Community Forum.
This is because the Simba Druid ODBC driver is reporting the time column as not searchable at the column level. Even though SQLGetTypeInfo might report the TIMESTAMP type as SEARCHABLE = 3, Power BI makes its actual decision based on the SEARCHABLE property returned by SQLColumns for that specific column. In your case, Power BI tries to apply a filter on time but sees SEARCHABLE = 0 (SQL_UNSEARCHABLE), so it refuses to fold the expression. That’s why no query is sent and you get the error.
Power BI DirectQuery still requires columns to be marked as SEARCHABLE (2 or 3) to apply filters or comparisons. This applies whether you're using Microsoft Fabric or the standard Power BI Desktop or Service. If you want filtering to work on time, you need to make sure the driver, either through its native code or metadata config returns SEARCHABLE = 2 or 3 for that column via SQLColumns. Simba drivers built on the SimbaEngine SDK support this, but it must be explicitly set in the metadata layer.
If you can't modify the driver, the practical workaround is to create a new Druid column that mirrors time but isn’t treated as special by the driver and is returned with the correct metadata. That column will work with filters in Power BI.
Understanding query evaluation and query folding in Power Query - Power Query | Microsoft Learn
SQLColumns Function - ODBC API Reference | Microsoft Learn
SQLGetTypeInfo Function - ODBC API Reference | Microsoft Learn
DirectQuery in Power BI - Power BI | Microsoft Learn
ODBC Data Source Administrator - Open Database Connectivity (ODBC) | Microsoft Learn
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