15.10 - Nonhashed Tables - Teradata Database

Teradata Database Data Dictionary

Product
Teradata Database
Release Number
15.10
Content Type
Administration
User Guide
Publication ID
B035-1092-151K
Language
English (United States)

When a table is nonhashed, the rows of the table are not distributed using hash maps and are instead stored AMP-locally. For example, each row of the DBC.DatabaseSpace table keeps track of the space used locally by one AMP. Similarly, recovery tables only contain the information necessary to recover any activity or transaction that occurred on their own AMP.

Acctg and DatabaseSpace are allowed for SHOW TABLE, HELP, and so on, and these two tables can be queried if you have the privileges for executing the statement on the table. Note that SHOW TABLE and HELP INDEX indicate these two tables have unique primary indexes even though they are actually nonhashed tables.

The other tables have special formats for their rows and cannot be queried and are not allowed for SHOW TABLE and so on (an error is returned that the table cannot be accessed).

The following table lists the nonhashed and NO FALLBACK Data Dictionary tables.

 

Nonhashed, NO FALLBACK Tables

Description

Acctg

Resource usage by Acct/User

ChangedRowJournal

Down-AMP recovery journal

DatabaseSpace

Database and table space accounting

LocalSessionStatusTable

Last request status by AMP

LocalTransactionStatusTable

Last transaction consensus status

OrdSysChngTable

AMP recovery journal

RecoveryLockTable

Recovery session locks

RecoveryPJTable

Permanent journal recovery

SavedTransactionStatus

AMP recovery table

SysRcvStatJournal

Recovery, Reconfig, and startup info

TransientJournal

Backout uncommitted transactions

UtilityLockJournalTable

Host utility lock records