TurboIMAGE/XL Database Management System Reference Manual MPE/iX V6.5 (30391-90011)

Chapter 7 347
Logging and Recovery
Roll-Forward Recovery
FILES RESTORED : 7
FILES RESTORED : 7
:
:RUN DBUTIL.PUB.SYS
HP30391C.07.00 TurboIMAGE/XL: DBUTIL (C) COPYRIGHT HEWLETT-PACKARD COMPANY 1987
>>show orders flags
For database ORDERS
Maintenance word is not present.
Access is enabled.
Autodefer is disabled.
Dumping is disabled.
Rollback recovery is disabled.
Recovery is disabled.
ILR is disabled.
Mustrecover is enabled.
Logging is enabled.
Prefetch is disabled.
Indexing is disabled.
HWMPUT is disabled.
Restart is disabled.
>>exit
In the above example, you will need to disable the access flag and enable the recovery flag.
Several databases can log to the same log file simultaneously because each call to DBOPEN
specifies the fully qualified name of the database. If all databases that logged to the same
log file are to be recovered simultaneously, then the appropriate backup copy of each
database must be restored prior to running the recovery system. However, if the recovery
system begins execution before a database has been restored, accidental recovery is
prevented if recovery has been disabled on the working database, as specified earlier in
"Logging Maintenance."
The TurboIMAGE/XL logging and recovery systems depend upon the exact correspondence
between the stored database backup copy and the working database on disk at the time
logging was initiated. The DBSTORE flag and time stamp, properly used, enforce this
condition. Therefore, it is recommended that you use DBSTORE or TurboSTORE/iX 7x24
True-Online Backup (with ONLINE=START or ONLINE=END option) to generate backup
copies.
For flexibility, in the event that you might use the STORE command without
ONLINE=START or ONLINE=END option to store the backup, the capability exists to
defeat the time stamp and DBSTORE flag mechanism, by using the NOSTAMP and
NOSTORE options of the >CONTROL command of DBRECOV. In this case, you must assume
responsibility for maintaining the correspondence between the backup copy and the log
file. Note that a database recovered with the wrong log file causes DBRECOV to generate
erroneous data in the database and that this condition cannot always be detected.
Modifications to the database before the database is recovered and with logging disabled
also cause the recovered database to be incorrect.