SESAM/SQL needs a PBI file in order to be able to ensure that SESAM backup copies (in the case of disk copy and online backup using ARCHIVE) have a consistent status when created online with the utility statement COPY ).
In the case of online backup using HSMS, an HSMS work file is used.
The contents of PBI file or the HSMS work file
In the PBI file, SESAM/SQL logs the physical before images (PBIs) of blocks modified by concurrent SQL statements and/or CALL DML statements during the copy operation.
Once a SESAM backup copy has been created online on disk, SESAM/SQL immediately adds the logged PBIs to the SESAM backup copy.
If backup is performed on magnetic tape cartridge using HSMS, HSMS is responsible for administering the before images. The HSMS work file contains the before images of blocks that are changed in the space to be backed up. HSMS administers the blocks changed over the course of the backup and reads the block to be backed up from the HSMS work file or from the space. Once the backup is complete, HSMS deletes the work file.
In the case of a SESAM backup copy on magnetic tape cartridge using ARCHIVE, SESAM/SQL also backs up the PBI file on magnetic tape cartridge. In this case the file is only read in at the time of repairing or resetting.
Storage medium, primary and secondary assignments
SESAM/SQL creates the PBI file or the HSMS work file as a temporary file that only exists for as long as it takes to create the SESAM backup copies online. The copies are created on the storage medium (disk) and the primary and secondary assignments are made in accordance with the information in the PBI media records in the media table.
The following default values apply for primary and secondary assignment of the PBI file or HSMS work file: 576 (primary assignment) and 72 (secondary assignment).
BS2000 file name
The PBI file or the HSMS work file have the following file name in BS2000: user_id.catalog.time_stamp.01
user_id | BS2000 user ID |