Resolve the support functions
When an SQL statement uses a user-defined aggregate, the database server resolves the support functions to the proper UDRs.
The database server resolves the support functions without a database owner name. Therefore, the user-defined function resolution logic attempts the following schemas, respectively: the current user, the schema of the argument types, and the HCL Informix® schema, respectively. For more information about routine resolution, refer to Understanding routine resolution.