When working with a data table based on "Impala" with "Load method" set to "Keep data table external", one cannot enable marking.

Marking in table visualizations is only supported if the view has a 'Primary Key' defined and the reason is that a primary key is required to know which rows to mark. Unfortunately, it is not possible to define the primary key using Impala when the data table is external. 

There are idea/enhancement requests in the TIBCO Ideas portal already which is in consideration to define the primary key with Impala:

• https://ideas.tibco.com/ideas/TS-I-5629 Impala Primary Key
• https://ideas.tibco.com/ideas/TS-I-5948 Manual setting of primary key column (Impala, DB2, etc)

In the meantime, you can enable marking by instead importing the data when creating your data table (in-memory) instead of having external (in-database).

This article discusses how to perform marking on data with Impala as the data source in TIBCO Spotfire

Doc: Working with In-Database Data

• https://docs.tibco.com/pub/sfire-analyst/11.4.0/doc/html/en-US/TIB_sfire-analyst_UsersGuide/data/data_working_with_in-database_data.htm