Database update log acquisition modes

HiRDB collects in a system log file historical information on database updating by UAPs and utilities^#. The user can specify that such a database update log not be collected. Processing time is reduced when a database update log is not collected, thereby reducing the UAP or utility execution time.

#: Applies to the following utilities only:

Database load utility
Database reorganization utility
Rebalancing utility

Organization of this section: (1) Database update log acquisition modes; (2) Specifying the database update log acquisition mode; (3) RECOVERY operand; (4) Operational differences depending on the database update log acquisition mode; (5) Notes on backup (important)

(1) Database update log acquisition modes

Three database update log acquisition modes are available during UAP or utility execution:

Log acquisition mode: Database update log information necessary for rollback and rollforward is acquired.

Pre-update log acquisition mode: Database update log information necessary for rollback only is acquired.

No-log mode: Database update log information is not acquired.

(2) Specifying the database update log acquisition mode

The following table lists the database update log acquisition modes.

Table 7-1 Database update log acquisition modes

Condition	Specification of database update log acquisition mode
UAP	Specify the database update log acquisition mode in the PDDBLOG operand of the client environment definition. The log acquisition mode or the no-log mode can be specified; the pre-update log acquisition mode cannot be specified.
Database load utility	Specify the database update log acquisition mode in the -l option of the database load utility.
Database reorganization utility	Specify the database update log acquisition mode in the -l option of the database reorganization utility.
Rebalancing utility	Specify the database update log acquisition mode in the -l option of the rebalancing utility. The log acquisition mode or the no-log mode can be specified; the pre-update log acquisition mode cannot be specified.
User LOB RDAREA being used	For the data stored in a user LOB RDAREA, specify the database update log acquisition mode in the RECOVERY operand of CREATE TABLE.

(3) RECOVERY operand

The database update log acquisition mode specified with the RECOVERY operand might be changed by the specification of the PDDBLOG operand or the -l option. The following table shows the relationship between the RECOVERY operand and the PDDBLOG operand or -l option.

Table 7-2 Relationship between the RECOVERY operand and the PDDBLOG operand or -l option

PDDBLOG operand or -l option specification	RECOVERY operand specification	Value assumed during UAP (or utility) execution
ALL a (Log acquisition mode)	ALL	ALL
	PARTIAL	PARTIAL
	NO	NO
p (Pre-update log acquisition mode)^#	ALL	PARTIAL
	PARTIAL	PARTIAL
	NO	NO
NO n (No-log mode)	ALL	NO
	PARTIAL	NO
	NO	NO

ALL or a: Log acquisition mode

PARTIAL or p: Pre-update log acquisition mode

NO or n: No-log mode

#: The pre-update log acquisition mode cannot be specified with the PDDBLOG operand.

(4) Operational differences depending on the database update log acquisition mode

The database update log acquisition mode that is used determines how the following operations are performed:

HiRDB processing and administrator actions when a UAP or utility terminates abnormally
Database recovery point

(a) HiRDB processing and administrator actions when a UAP or utility terminates abnormally

The following table describes the HiRDB processing and administrator actions when a UAP or utility terminates abnormally.

Table 7-3 HiRDB processing and administrator actions when a UAP or utility terminates abnormally

Database update log acquisition mode	HiRDB processing	User's action
Log acquisition mode	Rolls back any updated RDAREA to its status before the UAP executed or to its status immediately before the abnormal termination.	If the RDAREA was rolled back to its status before the UAP executed, re-execute the UAP. If it was rolled back to its status immediately before the abnormal termination, re-execute the processing subsequent to the synchronization point.
Pre-update log acquisition mode
No-log mode	Does not perform rollback. Places any updated RDAREA in error shutdown status (logless hold). The contents of the RDAREA are damaged.	Use the database recovery utility to restore the RDAREA from a backup made before the UAP executed, and then re-execute the UAP.

(b) Database recovery point

The following table shows the point to which the database can be recovered by the database recovery utility.

Table 7-4 Database recovery point

Database update log acquisition mode	Database recovery point
Log acquisition mode	Backup acquisition point or any synchronization point subsequent to the backup acquisition point
Pre-update log acquisition mode	Backup acquisition point
No-log mode	Backup acquisition point

(5) Notes on backup (important)

Do not make a backup in the updatable mode (-M s specified) during execution of a UAP (including utilities) in the no-log mode or the pre-update log acquisition mode.
After execution of a UAP (including utilities) in the no-log mode or the pre-update log acquisition mode, make a backup in one of the following modes:
- Referencing/updating-impossible mode (-M x specified)
- Referencing-permitted mode (-M r specified)