Database allocation record (ALLOC)

For Fast Path, DBRC creates an ALLOC record when the area is placed in OPEN-for-update status. For DL/I, DBRC creates an ALLOC record when IMS updates a DBDS the first time during a run of IMS or the first time after you enter a /DBRECOVERY command. This record contains the time stamp of its creation and the time stamp of the opening of the corresponding log. This time stamp identifies the log data sets containing the database change records that are needed for recovery. If the DBDS is subsequently deallocated, DBRC adds the time stamp of the deallocation to the ALLOC record.

DBRC automatically deletes allocation records if they are older than the oldest image copy record and if DBRC no longer needs them for database recovery. As DBRC deletes an ALLOC record, it changes the associated LOGALL record. This is part of the DBRC Image Copy utility exit routine processing. This automatic deletion of ALLOC records for a DBDS does not occur under either of the following conditions:

• The ALLOC record has no deallocation time.

  A deallocation time is recorded when the database or area has had the /DBR command run against it. Otherwise, the ALLOC record uses the log close time as an implicit deallocation time.

• The PRILOG record associated with the ALLOC record is open (it has a STOPTIME of zero) but is not marked in error.

In cases such as these, you can use the DELETE.ALLOC command to delete unwanted ALLOC records from the RECON data set. DBRC automatically updates allocation time stamps during online and concurrent image copy utility exit routine processing to move the allocation time stamps forward in time.