16.10 - RECONFIG - 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 RECONFIG command starts the reconfiguration process, which changes the Teradata Database system configuration. Prior to performing a reconfiguration, a new configuration map must have been defined using the Configuration utility.

The command can also be used to change certain reconfiguration parameters after the process has begun.

Syntax



DISPLAY
whether to enable or disable output of Reconfiguration status (but not statistics):
  • ON enables output. (Default)
  • OFF disables output.
n TASKS
the limitation of the number of Reconfiguration sessions running in parallel.
n is a number from 0 through 15. The default is 15.
Specifying 0 tasks pauses the reconfiguration.
[CPU | IO] PRIORITY p
the job settings to use for the reconfiguration. The default is to assign the reconfiguration process a medium timeshare access level.
Use the CPU and IO keywords to specify that the priority set is specific to either CPU or I/O time. If PRIORITY is specified with neither CPU nor IO modifiers, the priority specified is applied to both CPU and IO time.
Available settings for p are determined by workload settings. For more information about setting workload priorities, see the “Workload Designer” section in the Teradata Viewpoint User Guide. Search for “About Console Utilities.”
PAUSE
whether Reconfiguration is to pause before entering the auto-restart phase.
Each AMP stores the current phase of reconfiguration.
STATISTICS
whether to enable or disable output of Reconfiguration statistics:
  • ON enables statistics. (Default)
  • OFF disables statistics.

Usage Notes

The RECONFIG command can be used throughout the reconfiguration process to change the values of TASK, PRIORITY, JOURNAL MAXPERMSPACE, and STATISTICS.

The following table explains some of the Reconfig utility prompts.
Prompt Explanation
AMPs are added into configuration, do you want all new space to go to user DBC?
(yes or no) (If you choose no, added space is divided among the impacted databases and users in proportion to their current space allocations.)
When new AMPs are added to the system, this prompt lets you choose whether the new space is given exclusively to DBC, or divided proportionately among impacted databases and users.

As an example of dividing the new space proportionately among existing databases and users, if existing database db1 has a max perm space of x, and database db2 has a max perm space of 2x, when the space is expanded db1 would get additional space of y, and db2 would get additional space of 2y.

Which map should be the system-default map. (map name or number)?
The system default map is the contiguous map used for tables and join indexes subsequently created if no map is explicitly specified in the CREATE statement, and if the table creator has no other default map assigned. For more information on default map precedence, see SQL Data Definition Language - Syntax and Examples. When Reconfig starts, it displays the contiguous maps on the system with their corresponding map numbers. Map numbers 1 and 2 are reserved for Data Dictionary (DBC) tables, and cannot be specified as the system default map.
Reconfig will update the system-default map to newmap (Map Number nnnn).
Reconfig will make the new map available.
Which tables should reconfig process?

1. No tables
2. Dictionary tables
3. User tables with contiguous maps specified in  DBC.ReconfigRedistOrderTbl
4. All user tables with contiguous maps.
This prompt verifies the system default map and allows you to choose which tables should be processed by the Reconfiguration utility.

To shorten the time that the Reconfig utility keeps the system down and unavailable, you can choose No Tables, and, after the reconfiguration is complete, use the ALTER TABLE MAP statement to set existing user tables to use the new contiguous map. In this way their rows are redistributed in the background while the database is running and available. Alternatively, you can use the Advisor and Mover tool procedures to help automate this process. For more information about ALTER TABLE MAP, see SQL Data Definition Language - Syntax and Examples. For more information about the Advisor and Mover tools, see Database Administration.

Data Dictionary tables, if specified to be moved during the reconfiguration, must be moved by the Reconfiguration utility itself.

Example: Running RECONFIG suppressing statistics output

To disable statistics output, type:

reconfig with statistics off

Example: Running RECONFIG with 10 parallel sessions

To reconfigure with 10 control tasks and statistics output disabled, type:

reconfig with 10 tasks statistics off

Example: Running RECONFIG suppressing all display output

To reconfigure with eight control tasks and output display disabled, type:

reconfig with 8 tasks display off

Example: Typical RECONFIG output

This example shows some output from the RECONFIG command. Reconfiguration output displays the following:

  • Start and end time of each table processed during redistribution
  • Run-time statistics of the table process that includes statistics for all AMPs

This information is included with the deletion and NUSI building. The output might become excessive for a large number of tables, so you might want to disable DISPLAY. If you disable DISPLAY, you can still obtain status using the STATUS command.

You can disable the table begin/completion output with the RECONFIG WITH DISPLAY OFF command. You can disable the statistics output with the RECONFIG WITH STATISTICS OFF command.

08/05/13 09:04:35  Task 01 Begin redistribution DBC.Global (0000H 0019H).
08/05/13 09:04:35  Task 00 Begin redistribution DBC.TransientJournal (0000H 001AH).
08/05/13 09:04:35  Task 00 End redistribution DBC.TransientJournal (0000H 001AH).
  Statistics:        RowCount ByteCount TotSecs         CPUSecs        
 IOCount
     AllAmps:               0         0       0               0        
       0
08/05/13 09:04:36  Task 02 Begin redistribution DBC.Owners (0000H 001BH).
08/05/13 09:04:36  Task 01 End redistribution DBC.Global (0000H 0019H).
  Statistics:        RowCount ByteCount TotSecs         CPUSecs        
 IOCount
     AllAmps:               2         0       0               0        
   2,564
08/05/13 09:04:36  Task 00 Begin redistribution DBC.Parents (0000H 001CH).
08/05/13 09:04:36  Task 02 End redistribution DBC.Owners (0000H 001BH).
  Statistics:        RowCount ByteCount TotSecs         CPUSecs        
 IOCount
     AllAmps:              18         0       0               0        
   2,831
08/05/13 09:04:36  Task 00 End redistribution DBC.Parents (0000H 001CH).
  Statistics:        RowCount ByteCount TotSecs         CPUSecs        
 IOCount
     AllAmps:              13         0       0               0        
   2,943
08/05/13 09:04:36  Task 01 Begin redistribution DBC.ErrorMsgs (0000H 001EH).
08/05/13 09:04:36  Task 00 Begin redistribution DBC.ChangedRowJournal (0000H 0020H).
08/05/13 09:04:36  Task 00 End redistribution DBC.ChangedRowJournal (0000H 0020H).
  Statistics:        RowCount ByteCount TotSecs         CPUSecs        
 IOCount
     AllAmps:               0         0       0               0        
       0