The Dispatcher - Advanced SQL Engine - Teradata Database

Database Introduction

Product
Advanced SQL Engine
Teradata Database
Release Number
17.05
17.00
Published
June 2020
Language
English (United States)
Last Update
2021-01-23
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qia1556235689628.ditamap
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dita:id
B035-1091
lifecycle
previous
Product Category
Teradata Vantageā„¢

The Dispatcher controls the sequence in which steps are executed. It also passes the steps to the BYNET to be distributed to the AMP database management software as follows:

  1. The Dispatcher receives concrete steps from gncApply.
  2. The Dispatcher places the first step on the BYNET; tells the BYNET whether the step is for one AMP, several AMPS, or all AMPs; and waits for a completion response.

    Whenever possible, Teradata Database performs steps in parallel to enhance performance. If there are no dependencies between a step and the following step, the following step can be dispatched before the first step completes, and the two execute in parallel. If there is a dependency, for example, the following step requires as input the data produced by the first step, then the following step cannot be dispatched until the first step completes.

  3. The Dispatcher receives a completion response from all expected AMPs and places the next step on the BYNET. It continues to do this until all the AMP steps associated with a request are done.