17.10 - Ferret Commands - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - Database Utilities

Advanced SQL Engine
Teradata Database
Release Number
July 2021
English (United States)
Last Update
Ferret gives you a wide range of commands that allow you to display specific information about the Teradata system, and optimize the system to improve performance. Use Ferret commands to:
  • Define the level or scope of a command, such as one or more tables, vprocs, maps, cylinders, or the WAL log.
  • Display the parameters and scope of a previous action.
  • Perform an action to increase performance, such as moving data to reconfigure data blocks and cylinders.
  • Displaying utilization of storage space by percentage and cylinders.

Defining Command Parameters Using SCOPE

Some Ferret commands require that you first define the parameters, or scope, of the action you want to initiate.

The SCOPE command allows you to limit the command action in the following areas:

SCOPE Parameter Variables
  • A single AMP vproc
  • A range of AMP vprocs
  • All AMP vprocs in a configuration
  • The AMP vproc or range of AMP vprocs in a single contiguous map
  • The AMP vprocs in several contiguous maps
  • All maps, and therefore all AMP vprocs in a configuration
  • A single cylinder
  • A set of cylinders
  • A single table
  • A set of tables
  • All tables in the system
  • A class of tables
WAL The WAL log

For more information, see SCOPE.

Summary of Ferret Commands

The following table summarizes the Ferret commands, their valid scopes, and gives a brief description of the function of each command:

Command Valid SCOPE Options Function
COMPRESS Not Applicable Compresses data blocks of a specified table, or shows an estimate of what results would be if tables were compressed.
COMPRESS None Displays the current system day, date, and time.
DEFRAGMENT Vprocs or tables Combines free sectors, and moves them to the end of a cylinder.
DISABLE None Sets a specific flag in the file system to FALSE, disabling certain features of Ferret. Most such flags are for internal use only.
ENABLE None Sets a specific flag in the file system to TRUE, enabling certain features of Ferret. Most such flags are for internal use only.
ERRORS None Redirects diagnostic messages to a file that you specify or to the default file STDERR.

Using the ERRORS command, you can append an existing message file, overwrite an existing message file, write only to a new file, or display the current diagnostic message file.

FORCE None Sets the cylinders occupied by a table or range of rows, to a specified temperature, regardless of how frequently the data has been historically accessed.
HELP None Provides general help for Ferret or detailed help if you specify an option or parameter.
INPUT None Informs Ferret to read commands from a specified file rather than from the default input file STDIN.
MAP None Displays information about a specified map.
OUTPUT None Redirects Ferret output to a file you specify or to the default file STDOUT.
PACKDISK Vprocs or tables Reconfigures cylinders within a defined scope.
PRIORITY None Sets the priority class of the Ferret process.
QUIT None Ends a Ferret session.
RADIX None Sets the default radix used as the numeric base for Ferret data input and output.
RESETBLCTSKCNT None Resets the count of running COMPRESS and UNCOMPRESS tasks to zero.
RESETBLCTSKCNT WAL log, vprocs, or tables Performs a verification of the file system B-Tree structure.
SHOWAMPRECOVERYBLC   Displays which compress and uncompress operations that happen during system recovery to minimize transaction recovery time after a restart.
SHOWBLOCKS WAL log, vprocs, or tables Displays data block size and the number of rows per data block for a defined scope. Also indicates whether data blocks use block-level compression.
SHOWCOMPRESS Vprocs, and PERMANENT and JRNL tables Lists subtables that have data blocks using block-level compression.
SHOWDEFAULTS None Displays the current default radix for input and output, the current input, output, and error file names, and the current scope settings.
SHOWFSP Vprocs or tables Displays table names and space utilization for those tables that would free or consume some number of cylinders if PACKDISK is executed at a particular FSP. The scope can include one or more tables, one or more vprocs, or the entire system.
SHOWSPACE WAL log, vprocs, or tables Displays storage space utilization for permanent, spool, WAL log, temporary, and journal data, including the amount of free space remaining.
SHOWSPACE Vprocs, tables, or WAL log Displays information about cylinder allocation and temperature for cylinders in the currently set scope.
TABLEID None Displays the table number of the specified table when given the database name and table name.
UNCOMPRESS Not Applicable Uncompresses data blocks of a specified table, or shows an estimate of what results would be if tables were uncompressed.
The following Ferret commands are used with Teradata Virtual Storage, a storage product available from Teradata. For more information about these commands, see Teradata Vantage™ - Teradata® Virtual Storage, B035-1179:

Ferret Error Messages

All Ferret error messages are directed by default to your system console screen.

Ferret and file system error messages can be redirected through use of the ERRORS command.

For more information on file system messages, see Teradata Vantage™ - Database Messages, B035-1096.