Path Filtering Using a Key in the Path | NOS | Teradata Vantage - 17.10 - Path Filtering Using a Key in the Path of the Data Set - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - Native Object Store Getting Started Guide

Advanced SQL Engine
Teradata Database
Release Number
Release Date
July 2021
Content Type
Programming Reference
Publication ID
English (United States)

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.

  1. To run NOS-related commands, log on to the database as a user with the required privileges.
  2. 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