Key (or path) filtering reduces the number of external objects that are transferred to provide the result. This reduces the I/O performed on the external object store time and results in less work for the SQL Engine.
The examples and results show a sample river flow data set. To use your own data, replace the table and column names, and authorization object.
- To run NOS-related commands, log on to the database as a user with the required privileges.
- Create a foreign table or ask your database administrator to create the foreign table specifying a LOCATION that filters on site_no. Use the authorization object created in Controlling Foreign Table Access with an AUTHORIZATION Object:
SELECT TOP 2 GageHeight, Flow FROM riverflow_csv_pathfilter WHERE $path.$siteno = site_no;Where site_no is a site number value; for example, 09380000.
Your result will be similar to the following
GageHeight Flow ---------- ------ 10.16 17200 10.25 17700