USING FAST MODE - Teradata Vantage

Teradata® VantageCloud Lake
Deployment
VantageCloud
Edition
Lake
Product
Teradata Vantage
Published
January 2023
Language
English (United States)
Last Update
2024-04-03
dita:mapPath
phg1621910019905.ditamap
dita:ditavalPath
pny1626732985837.ditaval
dita:id
phg1621910019905
You can use this table_option with only two kinds of statements:
  • ALTER TABLE statement with no alter_option

    USING FAST MODE can only change the table format.

  • ALTER TABLE statement whose only alter_option is ADD COLUMN

    USING FAST MODE can change the table format and add columns.

The table format is either Fast Column Add (FCA) or non-FCA.

For a table in FCA format:
  • Every ADD COLUMN statement on the table includes an implicit USE FAST MODE ON clause.
  • If you update a column, columns with versions greater than the version of the updated column (v) do not materialize in the row if the row version is less than v.
  • If you drop one or more columns, the table converts to non-FCA format. Missing values in remaining columns materialize in the rows, which may increase table size.
FCA format advantages:
  • Dramatically reduces exclusive lock times that ADD COLUMN needs.
  • Adds columns without increasing table space, because added columns do not materialize immediately in existing rows.
FCA format does not support the following:
  • ADD COLUMN statements that increase row size from less than 64 KB to more than 1 MB
  • Column-partitioned tables
  • Dictionary tables
  • VOLATILE tables
  • GLOBAL TEMPORARY tables
  • QUEUE tables
  • ERROR tables
ON
Default when FastAlterEnable is set to true.
If non-FCA, the table format becomes FCA.
If the ALTER TABLE statement includes one or more ADD COLUMN options, the statement adds the specified column or columns to the table without altering the existing rows and adds the default values of the new columns to the table header.
OFF
If FCA, the table format becomes non-FCA.
FCA structures in the table header disappear, and missing values in remaining columns materialize in the rows, which may increase table size.
If the ALTER TABLE statement includes one or more ADD COLUMN options, the statement adds the specified column or columns to the table.