Nonhashed Data Dictionary Tables | Teradata Vantage - 17.00 - Nonhashed Tables - Teradata Database

Teradata Vantageā„¢ - Data Dictionary

prodname
Advanced SQL Engine
Teradata Database
vrm_release
17.00
created_date
June 2020
category
Administration
Programming Reference
featnum
B035-1092-170K

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