ROLLBACK erases all changes made to a database or selected tables of a database. Use ROLLBACK to roll back data tables on all or a subset of the processors. A rollback uses a single journal table as input. All objects in the object list must share the same journal table.
A rollback is not allowed over a data definition statement that changed a table’s structure. If Teradata ARC encounters such a change to a table during a rollback, the rollback for that table stops and the program prints a message in the output listing.
If an AMP is offline and a nonfallback table is being recovered with unique secondary indexes, Teradata ARC invalidates unique secondary indexes on the table. After the AMP returns online, drop and recreate the unique secondary indexes for that table.
RELEASE LOCK can be used instead of the RELEASE LOCK keywords. Use the RELEASE LOCK statement to release all HUT locks and the RELEASE LOCK keyword to release specific HUT locks.
To roll forward using a current single image journal, first roll back to the checkpoint. After the rollback has completed, use ROLLFORWARD to restore the data.
Note: When a PPI table or a Column Partition (CP) table is restored, Teradata ARC automatically executes the Revalidate step during the BUILD phase. The Revalidate process increases the Util version of the table. This is considered to be a structural change to the table. Because of this change, a PPI table or a CP table cannot be recovered using either the RollBack or RollForward operation after it is restored.
chkptname Parameter
Use CHECKPOINT to generate the checkpoint for the journal used in the recovery (the one for the data tables that will be rolled back).
With this option, Teradata ARC scans the journal table for the identified checkpoint. If that checkpoint does not exist, Teradata ARC returns an error.
If an unqualified chkptname is used and there are multiple rows in the journal table that all have the same name, Teradata ARC uses the last chronological entry made. In the ROLLFORWARD statement, on the other hand, Teradata ARC uses the first chronological entry made.
Alpha characters in a chkptname are not case sensitive. For example, chkptname ABC is equal to chkptname abc. If this option is not specified, Teradata ARC uses the entire journal table.
DELETE Keyword
Do not specify any DELETE options when using the current journal for the recovery. Use NO DELETE when recovering selected tables and then later want to recover the balance of the tables that might have changes in the journal.
ABORT Keyword
ABORT aborts an all-AMPs roll operation that includes non-fallback tables or single copy journal tables if an AMP is down. This option does not affect specific AMP roll operations.
PRIMARY DATA Keywords
Use this keyword phrase to reduce the amount of I/O during rollback. Using this option improves the rollback performance when recovering a specific AMP from a disk failure.
If a specific AMP is recovered, unique indexes are invalid. Always follow a ROLLBACK statement that uses the PRIMARY DATA option with a BUILD statement.