16.20 - BEGIN OPTIMIZE - Teradata Database - Teradata Vantage NewSQL Engine

Teradata Vantage™ - Teradata® Virtual Storage

Product
Teradata Database
Teradata Vantage NewSQL Engine
Release Number
16.20
Published
March 2019
Language
English (United States)
Last Update
2019-05-02
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Purpose

Initiates immediate, high-priority migrations necessary to move cylinders modified by the FORCE command to appropriate classes of storage. Normal migration is a background process with a lower priority.

BEGIN OPTIMIZE initiates optimization on all nodes and all tables of the system, not just the tables on which the FORCE command was recently used.

Optimization can cause extremely heavy loads on system resources, and have a negative impact on system performance. If BEGIN OPTIMIZE is used on a production system, it should be used only during scheduled maintenance windows.

Syntax



Usage Notes

Migrations resulting from BEGIN OPTIMIZE occur at the maximum possible speed, without regard to potential impacts to existing workloads. Because cylinders marked HOT or COLD using the FORCE command are at the maximum temperature extremes, these cylinders are likely to be the first selected for migration, depending on available space.

If space on storage media of appropriate performance grade is not available, some cylinders are moved out of FAST and SLOW storage locations to make room for the HOT and COLD table data, respectively.

Example: BEGIN OPTIMIZE

Ferret  ==>
> begin optimize

BEGIN OPTIMIZE command could consume significant system resources
        Do you wish to continue?? (Y/N)
> Y
Optimization has been started on all vprocs

If you wish to revert this optimization to a low level background mode, you can issue a CANCEL OPTIMIZE command