DUMP command

Summary

Privileges

File manager

Function

Backs up a Model 204 file to a sequential data set

Syntax

DUMP TO ddname [NBUFF I/Obuffers]

Where

ddname	Is the name of the sequential dataset to which the file is written.
I/Obuffers	Optionally sets the number of sequential I/O buffers DUMP can use. For example: DUMP TO TESTFILE NBUFF 50 Each buffer is equal in size to the blocksize of the sequential dataset. Thus, if NBUFF is 20, and the sequential dataset blocksize is 30920 bytes, 618,400 bytes of storage will be needed for the sequential I/O buffers. NBUFF can be set to any number between 1 and 99 inclusive.

Syntax notes

DUMP must be issued in file context (that is, the current default must be a file, not a group).

Example

OPEN PEOPLE M204.0620: FILE PEOPLE OPENED M204.1203: FILE PEOPLE WAS LAST UPDATED ON hh:mm:ss DUMP TO DUMPPEOP M204.1760: FILE PEOPLE: DUMP BEGINNING AT hh:mm:ss M204.1761: FILE PEOPLE: DUMP COMPLETED AT hh:mm:ss CLOSE PEOPLE

Usage notes

The DUMP command copies an open Model 204 file to a sequential data set that is located on either a magnetic tape or a direct access device. DUMP backs up a file so that the dumped version is available in case of a system or media failure. The dumped version can subsequently be restored using either the RESTORE command or the REGENERATE command.

Note: Use the DUMP command before using either the REGENERATE or the RESTORE command. DUMP updates the file while making a backup copy (to a target media). Otherwise, when you do a media recovery using either REGENERATE (to include journals) or RESTORE (without journals), the backup copy does not incorporate all updates, but you cannot detect this.

If a file is skewed, the file can be transferred from one device type to another only through the Model 204 DUMP/RESTORE facility. File skewing is an obsolete feature.

Dump files can be accessed and updated during execution of the DUMP command. After the DUMP command has been issued, the DUMP waits until all existing transactions that might update the file are complete and the existing copy of the file is in a consistent state. At that point the DUMP begins. If a subsequent user request updates the file being dumped, preimages of database pages to be updated are dumped before the update is allowed. The dumped copy matches the state of the file at the time the DUMP begins.

If updates are not complete when the DUMP command for a file is issued, you receive a message that the file is still in use. The DUMP can be canceled at this juncture. If errors are detected during the file dump, the dump is ended. A message to this effect is displayed.

Job level enqueuing is not affected by this facility. A BATCH204 job cannot be started to dump files that are being updated in another Model 204 job. Use of the DUMP command from any Model 204 job requires exclusive access to the file by that copy of Model 204.

If an external security interface is active, the user ID issuing the command is checked for the proper data set usage authorization. If the authorization check fails, the attempt is logged as a security violation and the command is not executed.

With a security interface, you must have WRITE, ALTER, or UPDATE privileges to use the DUMP command with sequential data sets. For more information, refer to the Security interfaces pages.

When it processes DUMP, Model 204 ends any update unit in progress and begins a non-backoutable update unit.

The DUMP, RESTORE, and REGENERATE commands and their use in dumping, restoring, and regenerating files are explained in File dumping and restoring and Media recovery.