15.00 - FREESPACE PERCENT - Teradata Database

Teradata Database SQL Data Definition Language Detailed Topics

prodname
Teradata Database
vrm_release
15.00
category
Programming Reference
featnum
B035-1184-015K

FREESPACE PERCENT

FREESPACE = n PERCENT specifies the value for the percent freespace attribute, where n is an integer constant. n percent free space remains on each cylinder during bulk data load operations on the table. PERCENT is an unnecessary keyword and does not affect the semantics of the specification.

Note: Not all Teradata Database operations honor the freespace percentage you specify in a CREATE TABLE request. The following table lists which operations honor the specified freespace percentage and which do not.

 

                          Operations That Honor FREESPACE

         Operations That Do Not Honor FREESPACE

  • FastLoad data loads
  • MultiLoad data loads into unpopulated tables
  • Archive/Recovery RESTORE
  • Table Rebuild
  • Reconfiguration
  • Ferret PACKDISK
  • MiniCylPack
  • If few cylinders are available, and storage space is limiting, MiniCylPack might not be able to honor the specified FREESPACE value.

  • ALTER TABLE request that adds fallback protection to a table
  • CREATE INDEX request that defines or redefines a secondary index on a populated table
  • Creation of a fallback table during an INSERT … SELECT operation into an empty table that is defined with fallback.
  • Creation of a secondary index during an INSERT … SELECT operation into an empty table that is defined with a secondary index.
  • SQL INSERT operations
  • Teradata Parallel Data Pump INSERT operations
  • MultiLoad data loads into populated tables.
  • The FREESPACE value returned in response to a SHOW TABLE request is either the value specified in the CREATE TABLE request for the table or the value specified by the most recent ALTER TABLE request.

    Note: Do not use the Ferret utility PACKDISK command to change this value once you have created a table or have modified its FREESPACE PERCENT with an ALTER TABLE request.

    Instead, submit an ALTER TABLE request (see “ALTER TABLE (Basic Table Parameters)” on page 31) to change the free space percent value for the table and then immediately afterward submit a PACKDISK command that specifies the same free space percent value you set with that ALTER TABLE request (see the documentation for the Ferret utility in Utilities: Volume 1 (A-K) for more information and instructions for running PACKDISK).

    The reason for this is as follows: if you manually submit a PACKDISK command and specify a free space percentage on the command line, PACKDISK packs or unpacks the cylinders for the table to match the specified free space percentage. However, if the free space percentage you specify differs from the value specified for the table when it was created or last altered, Teradata Database starts a new AutoCylPack task immediately after PACKDISK completes, and this AutoCylPack operation nullifies the free space percentage you had just specified with PACKDISK to realign it with the free space percentage specified when you created or last altered the table.