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|