Filter to Retrieve CSV Data Efficiently | Native Object Store | Teradata Vantage - 17.10 - Using Filtering to Retrieve CSV Data More Efficiently - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - Native Object Store Getting Started Guide

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Release Date
July 2021
Content Type
Programming Reference
Publication ID
B035-1214-171K
Language
English (United States)

Reading all the objects in a bucket can be time-consuming and expensive. An alternative solution is to filter the object store using one or both of the following filtering methods:

Path Filtering
  • A path is a series of values that constitute a multi-level key (siteno, year, month, day) which identifies one or more objects within an object store.
  • Path filtering lets you filter and reduce the amount of objects you bring back to the database by providing specified values for different levels in a path key (for example, "WHERE $path.$siteno = '09380000'")
  • Path filtering is the most efficient way to read a selected portion on object store.
Payload Filtering
  • The payload column within a foreign table contains all of the values within an object.
  • In payload filtering you apply a filter to the data itself and not to the partitioning (path key) of the object store.
  • When filtering is applied to a column in the data (such as WHERE Flow > '15'), all objects in the object store have to be brought inside the database and be transformed prior to applying filtering.
  • When given a choice, this is usually less efficient because it will incur greater effort at both the object store level and the database level than does path filtering.