15.00 - 15.10 - The Dispatcher - Teradata Database

Teradata Database Introduction to Teradata

Teradata Database
Release Number
Content Type
User Guide
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English (United States)
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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:

The Dispatcher receives concrete steps from gncApply. 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.

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.