The SQL Service Module manages SQL queries sent to an SQL data service from a third-party client tool.
When the Data Integration Service receives an SQL query from a third-party client tool, the SQL Service Module sends the SQL statement to the LDTM for optimization and compilation. The LDTM passes the compiled SQL statement to a DTM instance to run the SQL query against the virtual tables in the SQL data service.
If you do not cache the data when you deploy an SQL data service, a DTM instance is started to run the SQL data service. Every time the third-party client tool sends an SQL query to the virtual database, the DTM instance reads data from the source tables instead of cache tables.