TurboIMAGE/XL Database Management System Reference Manual (30391-90012)

Chapter 7 327
Logging and Recovery
Logging Preparation
Example
:BUILD ORDER001;CODE=LOG;DISC=200000,20,7
Step 5--Creating the Log Identifier
You create the log identifier on MPE/iX by using the GETLOG command shown in this
section. A log identifier (logid) is a unique logical name that identifies a system logging
process to which log records are passed. Before using the GETLOG command, use the
MPE/iX LISTLOG command to check if the logid already exists on MPE/iX. The LISTLOG
command lists all logging identifiers, including creator names, log file names, and whether
or not the AUTO option is used.
If the logid exists and was created by someone else, you must specify a different logid. If
the logid exists and was created by you, check the parameters to verify that they are the
ones you want. If you find, for example, that you used the default NOAUTO option and you
want to change it to AUTO, you can either change it with the MPE/iX ALTLOG command, or
you can release the logid with the MPE/iX RELLOG command and then re-create it with the
GETLOG command. You can release a logid only if you are the creator of that logid.
The logid has a maximum of eight characters. Other users can access the log file and
records in the same log file by using the logid you acquire and its password. To access the
logging system directly through MPE/iX, you must have logging (LG) or operator (OP)
capability and supply the identifier and password on the OPENLOG intrinsic.
If you use logging and create a backup copy using TurboSTORE/iX 7x24 True-Online
Backup (with ONLINE=START or ONLINE=END), you can use either the default
NOAUTO option or use the AUTO option. At database backup time, using TurboSTORE/iX
7X24 True-Online Backup (with ONLINE=START or ONLINE=END), the necessary
information (such as the DBSTORE flag, name of the log file in use, the log record number,
date, and time stamps) is recorded in the database root file before backup. At roll-forward
recovery time using DBRECOV, this information is used to determine the log file to be used
and the position in the log file from where roll-forward recovery must begin. With the
NOAUTO option, there is only one log file. When using the AUTO option, the log file next
in sequence in a round-robin fashion is automatically created. Hence there can be more
than one log file needed for roll-forward recovery. In this case, it is very important to
maintain a process of synchronizing the log files with the backup copy. It is required that
the AUTO/NOAUTO option be not changed after backup and while the log process is
active. You can change it only when starting a new log cycle. Refer to step 8 later in this
chapter.
Syntax
:GETLOG
logid ;LOG= logfile , {DISC/TAPE}[;PASS= password ] [;{AUTO/NOAUTO}]
Parameters
logid is the logging identifier to be established on the system. It consists of a
string of up to eight characters that is meaningful to the user application.