PACKDISK - Advanced SQL Engine - Teradata Database

The PACKDISK command arranges (packs and unpacks) data on the storage associated with the tables in the current scope, leaving a specified percentage, the free space percent (FSP), of the storage empty. This allows for table growth within the currently allocated storage, and can free up cylinders for new storage allocations.

Syntax

PACKDISK
  [ /Y ]
  [ { FREESPACEPERCENT | FREE | FSP } [=] number ]
  [ FORCE ]

Syntax Elements

/Y

To bypass user confirmation.

If you do not specify the /Y option, then Ferret requests for user confirmation before proceeding with PACKDISK.

FREESPACEPERCENT

FREE

FSP

Optionally specifies the percentage of storage space that PACKDISK should leave unoccupied on cylinders for tables in the current scope. This free space percent (FSP) allows tables to grow in place, deferring the need for allocation of new free storage cylinders.

Because read-only tables do not grow, they do not require free space.

The FSP for a table can also be specified when the table is created or modified using CREATE TABLE and ALTER TABLE statements. If defined for a table, this FSP value takes precedence over the PACKDISK FREESPACEPERCENT value, unless the FORCE option is used.

If FREESPACEPERCENT is not specified with PACKDISK, and no FSP was specified with CREATE TABLE or ALTER TABLE, PACKDISK uses the free space percent value defined by the FreeSpacePercent setting in DBS Control.

number

Percentage of storage space to be left free in the cylinders of tables in the current scope.

FORCE

Forces PACKDISK to pack table data to the FREESPACEPERCENT value, regardless of current FSP values that might have been set using CREATE TABLE or ALTER TABLE statements.

For tables that have an FSP set with CREATE TABLE or ALTER TABLE, results from using the FORCE option of PACKDISK are only temporary. When the periodic background AutoCylPack task runs, it returns table free space to the FSP value set using CREATE TABLE or ALTER TABLE statements. IF FORCE is not used, PACKDISK honors the current FSP values that have been explicitly set using CREATE TABLE or ALTER TABLE. For tables with no explicit FSP, PACKDISK uses the system default defined in DBS Control.