Changes the user logging file without stopping or interrupting
the logging process.
Operation Notes |
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This command permits the user to change the active logging
file without stopping the logging process with the LOG
logid, STOP
command. By specifying a device, you may switch the logging file
from one device to another, regardless of the device on which the
logging file was created. If you enable automatic logging with the
ALTLOG or GETLOG
command, however, the only device available for logging is the default,
DISC.
If a log file is restricted to a single volume or volume class
when it is created with the BUILD
command, then successive log files created by User Logging will
have the same restriction.
If the CHANGELOG
command is valid, the system writes a changelog record to the end
of the current logging file and closes the file. It then opens a
new logging file whose characteristics are identical to those of
the preceding file and makes the new file permanent. If the system
is unable to open a new file of the same size, it tries to open
a new file half the size of the old file. It repeats this process
until a new file is opened successfully, or until the size is less
than 256 records. In the second case, user logging terminates.
If the system opens a new log file, it immediately writes
a changelog record to the new file. The changelog record posted
to the old logging file contains the fully qualified identifier
of the new logging file. A corresponding changelog record written
to the new file contains the fully qualified identifier of the old
logging file. Changelog records also contain the device type of
the logging file to which the changelog refers.
The following message is displayed on the $STDLIST
to confirm a successful change:
Log file for logid AAA has been changed from
A001.PUB.SYS to A002.PUB.SYS (ulogmsg 38) |
If the new logging file is a serial file, a message advising
the operator to mount the new log file appears on the console:
Mount new tape volume for changelog of logid AAA
(ulogmsg 40). |
Normally when a user logging file is full, the system terminates
the logging process and displays an appropriate message.
However, by specifying the AUTO
parameter in a GETLOG
or ALTLOG command,
you enable an automatic CHANGELOG,
thereby eliminating the need to issue the CHANGELOG
command manually. Refer to the ALTLOG
and GETLOG commands
in this chapter.
To use CHANGELOG
(manually or automatically), end the first user logging file name
with the numeric characters 001 (for example, fname001).
This establishes a naming convention that works in conjunction with
the file set number to generate sequential file names independently.
New file names consist of the file name root (fname)
plus the next sequential increment of the last three digits:
Current File Next File
TEST001 TEST002
TEST002 TEST003
... ...
TEST998 TEST999
TEST999 TEST000 |
The logging process opens files, and automatically names them
with the next sequential number, up to a maximum of 999. Thereafter,
the numbering sequence resets to 000 and begins incrementing all
over again.
Automatic logging with the CHANGELOG
command is available only for disk files.
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 | NOTE: The logging process specified by logid
must be in an ACTIVE state. If the logging process is in any other
state, such as RECOVERING, STOP, INITIALIZING, or if the logging
process has another CHANGELOG
pending, the command terminates in an error state. The ALTLOG
command permits changing the log file for an inactive logging process.
ALTLOG, however,
does not provide a way to link log files into a set. |
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Use |
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This command may be issued from a session, job, program, or
in BREAK. Pressing Break has
no effect on this command.
You must be the logid creator or
have system manager (SM) or system supervisor (OP) capability to
use the CHANGELOG
command. User logging (LG) capability is also required.
