SQL/MP Reference Manual

HP NonStop SQL/MP Reference Manual—523352-013
A-59
Considerations—APPENDRESTART
Considerations—APPENDRESTART

APPENDRESTART has the same authorization requirements as the APPEND
command. For more information about authorization requirements for
APPENDRESTART, see APPEND Command on page A-52.

APPENDRESTART verifies that the information in recovery-file accurately
describes both the source file and the target table (or partition). Using the
information in recovery-file, APPENDRESTART restores the target table to
the state it was in before the APPEND operation began. APPENDRESTART
proceeds with the original APPEND operation, appending data from the source file
to the end of the restored target table.
After the APPENDRESTART operation finishes, the target table or partition is
accessible to applications again.
The APPENDRESTART operation is likely to take as long as the original APPEND
operation, even if the interruption occurred when the APPEND operation was, for
example, halfway finished. This operation time occurs because APPENDRESTART
starts over at the beginning of the APPEND operation, adding all the data to the
target table that would have been added by APPEND.
In one case, however, APPENDRESTART is likely to execute in a very short time.
Suppose that an APPEND operation finishes writing data to the target table and is
interrupted at the end of the operation, when it is clearing corrupt flags. The
subsequent APPENDRESTART operation recognizes that all the data has been
successfully appended. In that case, APPENDRESTART does not restore the
target table to its original state. Instead, it simply finishes clearing corrupt flags and
completes the operation.

The APPEND operation creates a recovery file specified by recovery-file.
During normal operation, the APPEND utility purges recovery-file after it
successfully finishes adding data to the end of the target table.
However, if a processor or process failure interrupts the APPEND operation,
recovery-file is not purged and should continue to exist and be available for
APPENDRESTART; the only exception is if the interruption occurs early in the
APPEND operation, before APPEND finishes creating recovery-file. In that
case, you cannot use APPENDRESTART to recover from the failure. Instead, use
the APPEND command again. APPEND accepts an existing recovery-file if it
is incomplete, and writes fresh recovery information to recovery-file.