SQL/MP Reference Manual

HP NonStop SQL/MP Reference Manual—523352-013
A-54
Considerations—APPEND

A recovery file contains information needed to restore the target table to its original
state if the APPEND operation fails. Before appending any data to a table or table
partition, APPEND checks for the presence of a recovery file. If the file does not
exist or exists but contains incomplete recovery data, the APPEND command
executes normally, as described below. If the file exists and contains recovery data
or is not a recovery file, APPEND fails. In the normal case, APPEND executes:

Creates a new recovery-file

Gathers information about the current state of out-file

Writes this information to recovery-file

Appends data from in-file to out-file

Purges recovery-file in these situations:

The APPEND operation completes successfully

The APPEND operation terminates with an error but APPEND successfully
restores the target table to its original state

The APPEND operation can terminate without completing its task under two
general conditions:

An error causes the APPEND operation to terminate gracefully.
If the APPEND operation terminates with an error, it attempts to use the
recovery information in recovery-file to restore the target table to its
original state (that is, the state the table was in before the APPEND operation
was started). If APPEND succeeds in restoring the target table to its initial
state, the APPEND operation purges recovery-file.
In this case, the APPEND operation did not successfully complete, and no
recovery-file exists. Thus, the absence of recovery-file after an
APPEND operation does not always mean that the operation was successful.
To determine if the APPEND operation succeeded, check the SQLCI listing to
see if error messages occurred.

A processor or process failure interrupts the APPEND operation so that it
cannot terminate gracefully.
If the APPEND operation is interrupted and cannot restore the target table to
its original state, it does not purge recovery-file. In this case, the target
table or partition remains unavailable to applications until some recovery is
performed.
To recover from an interrupted APPEND operation and complete the operation,
use the APPENDRESTART command. You must specify exactly the same
parameters, including the same recovery-file, as you did in the initial
APPEND command.
To recover from an interrupted APPEND operation and simply restore the
target table to its original state, use the APPENDCANCEL command. After an