Special columns
Deployment options: Netezza Performance Server for Cloud Pak for Data System
Netezza Performance Server for Cloud Pak for Data
The backup and restore method that you use affects how the system retains specials. The term
specials refers to the end-user-invisible columns in every table that the system
maintains. The specials include rowid, datasliceid,
createxid, and deletexid.
The
following table describes how the backup method affects these values.
| Special | The nzbackup and nzrestore commands | Compressed external tables | Text format external tables |
|---|---|---|---|
rowid |
Retain. | Retain. | Not unloaded. |
datasliceid |
Retain when the system model size stays the same, otherwise recalculates. | Retain when the model size stays the same, otherwise recalculates. | Recalculate. |
createxid |
Receive the transaction ID of transaction that does the restore. | Receive the transaction ID of transaction that does the restore. | Receive the transaction ID of transaction that does the restore. |
deletexid |
Set to zero. | Set to zero. | Set to zero. |