16.10 - DEL AMP - Teradata Database

Teradata Database Support Utilities

prodname
Teradata Database
vrm_release
16.10
created_date
June 2017
category
Configuration
featnum
B035-1180-161K

Purpose

The DEL AMP command deletes an AMP or a range of AMPs from the new configuration map, or from a new contiguous map.

Syntax



mmmlist
One or a continuous range of AMP vproc numbers to be removed from the configuration or excluded from a new contiguous map.
AMP vprocs are numbered consecutively starting from 0.

Usage Notes

Use DEL AMP when system storage decreases, or when you want to create an additional, special-purpose contiguous map that includes only a subset of system AMPs. When you delete AMPs, Config asks you whether the AMPs should be deleted physically or logically:

  • When system storage will be decreased, you will physically delete AMPs from the configuration.
    • You can only physically delete AMPs at the high-end of the range of AMPs on the system.
    • Before you run the Reconfig utility to implement the changes, you must either use ALTER TABLE MAP to move user tables to maps that do not contain any of the AMPs that will be deleted, or drop tables (if they are no longer needed) that use maps having AMPs to be deleted.
  • When system storage remains the same, but you want to create a contiguous map that uses fewer than all AMPs in the system, you will logically delete AMPs from the configuration.
    • You can logically delete AMPs from both the low and high ends of the range of AMPs on the system.
    • You do not need to run the Reconfiguration utility to create the new contiguous map. The map is available immediately when the Config session ends.

If you type the DEL AMP command before the BEGIN CONFIG command, the command is ignored.

Example: Physically deleting AMPs due to reduced storage

Assume the current system global contiguous map (TD_GlobalMap), containing all system AMPs, contains 100 AMPs with vproc numbers 0-99. To prepare for the system storage being reduced by half, AMPs must be physically deleted from the configuration. Because this will be a physical deletion, only AMPs at the top of the AMP range can be deleted.

da 50-99

OK.
The AMPs 50 to 99 are deleted.
end config

OK.
: 6040
New contiguous map matches contiguous map in TD_Map1.
Will AMPs 50 to 99 be physically deleted with reconfig/vconfig?
yes
The session is terminated. The new global map is updated for reconfig (matching TD_Map1).

Example: Logically deleting AMPs to create a smaller contiguous map

Assume the current system global contiguous map (TD_GlobalMap), containing all system AMPs, contains 100 AMPs with vproc numbers 0-99. To create an additional contiguous map that uses fewer than the full system complement of AMPs, AMPs can be logically deleted, without physically deleting the AMPs from the system and without modifying the system global contiguous map. Because this is a logical deletion, the AMPs can be deleted from either end, or from both ends of the full range of system AMPs.

da 0-49

OK.
The AMPs 0 to 49 are deleted.
end config
OK.
Will AMPs 0 to 49 be physically deleted with reconfig/vconfig?
no
The session is terminated. TD_Map4 is saved.

The new contiguous map, TD_Map4, has the same fallback clustering as AMPs 50-99 in the global map.