USER_DATASTORE Editing Procedure after Indexing
When you change or edit the stored procedure, indexes based on it will not be notified, so you must manually re-create such indexes. So if the stored procedure makes use of other columns, and those column values change, the row will not be re-indexed. The row is re-indexed only when the indexed column changes.
output_type
Specify the datatype of the second argument to procedure. You can use either CLOB, BLOB, CLOB_LOC, BLOB_LOC, or VARCHAR2.