The Send Object Lock Message command sends a break message to
workstations that have jobs with locks on up to 100 different named
objects. An option exists to end the jobs after sending a break
message. SNDOBJLCKM can be used to inform users that an exclusive
function is needed for the objects and ending of the jobs is
required. A listing that describes the actions taken is displayed or
output.
You must have *JOBCTL special authority to use SNDOBJLCKM.
A typical command would be:
SNDOBJLCKM OBJ((LIBA QSYS *LIB)) ACTION(*SEND) +
MSG('Please signoff as backup +
will begin to LIBA in 30 minutes.') +
Break messages would be sent to all workstations where the job has a
lock on library LIBA. Because the system places a lock on LIBA if it
is on a job's library list, this technique can be effective in
determining who is using an application. If the same job name exists
for multiple interactive jobs and each holds a lock on one or more of
the named objects, only a single message will be sent. See the later
discussion of 'Multiple Jobs at a Workstation'. A listing would be
displayed with the list of users and any batch jobs that hold a lock.
After a 15 minute delay, you could send another message with a
stronger wording.
After a 30 minute time period, you could end the jobs holding a lock
by:
SNDOBJLCKM OBJ((LIBA QSYS *LIB)) ACTION(*ENDJOB) +
MSG('Your job will end in 10 seconds.) +
DLYJOBWAIT(10)
If ACTION(*CHECK) had been specified, the listing of who has the
locks would be displayed without sending any messages or ending any
jobs.
SNDOBJLCKM could be run at a specific time using a function such as
the Job Scheduler.
An option exists to send a message to a message queue if any batch
job holds a lock on the named objects. This would allow a system
operator to take action in addition to the interactive users.
Another option allows an escape message to be sent if batch jobs
exist that hold the specified locks.
You may optionally omit specific jobs or users.
While the system does place a lock on any library that is on an
active job's library list, the system does not lock a program when it
is called (nor the library where the program exists). If the program
opens a data base file, a lock is placed on the file, but not the
library. Consequently, ending all locks on the library object does
not guarantee that objects within the library are not being used.
SNDOBJLCKM allows the sending of messages to jobs for up to 100 named
objects that have locks. Only a single message is sent to a
workstation regardless of:
** If a job has more than one of the specified objects locked.
** If multiple jobs at the same workstation have one or more of
the specified locks.
For example, you can send a message if you have more than one library
that needs to be backed up and the libraries are on library lists.
Or you may want to backup a a specific library that is on library
lists, but other users may have a lock on a specific file or files
within the same library without having the library on their library
list.
System lock support
-------------------
Most actions that change objects will cause a lock to be placed on an
object while the system performs a function. A file that is open for
any function will have a lock. Neither of these functions will cause
a lock on the library where the object exists.
Locking a library typically occurs because the library is on a job's
library list.
Most locking occurs implicitly such as when a file is opened. The
ALCOBJ command may be used to specifically lock an object.
Not all object types may be locked. Different lock levels are
available for different object types such as *SHRRD (shared for read)
and *EXCL (exclusive). Not all object types allow all lock levels.
Note the major exception to system locking is with program objects.
The system does not lock a program when it is called (nor the library
where the program exists). The only full proof method of determining
that a library is not being used is to shutdown to the restricted
state.
However, if you are attempting to back up a library, 'read only'
objects such as programs, display files, and commands can be saved
even if they are being used.
What happens with SNDOBJLCKM when a user goes home
--------------------------------------------------
If an interactive user has gone home and still retains a lock on one
or more of the specified objects, the message sent by SNDOBJLCKM will
cause a break at the workstation. The message is displayed and
remains there until either the Enter key is pressed or the job is
ended. If an additional message is sent by SNDOBJLCKM, it will not
be displayed (the first message is still displayed).
If ACTION(*ENDJOB) is specified, the job will be ended after the
delay times. If multiple jobs are active at the same workstation,
you can end all jobs by specifying ADLINTJOBS(*ALL). Depending on
the type of jobs, this may take a few minutes.
ENDJOB Command used
-------------------
Some parameters are passed thru by the SNDOBJLCKM command and some
take the defaults on ENDJOB.
** The DELAY parameter is passed thru from SNDOBJLCKM. The
default is the same as on ENDJOB (30 seconds).
** The ADLINTJOBS parameter is passed thru from SNDOBJLCKM. The
default is the same as on ENDJOB (*NONE).
** The other parameters default to the ENDJOB parameters such as
OPTION(*CNTRLD).
Multiple Jobs at a Workstation
------------------------------
Some workstation devices support a 'hot key' to switch to a different
job. These are considered different job names and would act like
different workstations.
The Operating System supports two methods of having multiple jobs at
the same workstation 1) System Request and 2) Group jobs.
The break message that occurs goes to the workstation message queue
(not the user's message queue). If there are multiple jobs at the
same workstation, this may cause some confusion as the active job may
not hold the lock that you are attempting to free up. Your message
text should account for this.
Because of the way the system handles jobs that are not active at the
workstation, you must consider the use of ADLINTJOBS(*ALL).
** System request jobs
A system request job may have the same or a different user
name.
If the default of ADLINTJOBS(*NONE) is used and the job
that is active has the lock, it will be ended. The
inactive job will then become the active job.
If the default of ADLINTJOBS(*NONE) is used and the
secondary job (function of 'PGM-QMNSYSRQ') is the one
you are attempting to end, it will not end until the
user transfers back to the job. If the user has gone
home, the job will not end. If the user switches to
the job holding the lock, the job will be ended after
the ENDJOB DELAY limit has been reached.
If ADLINTJOBS(*ALL) is specified, all jobs will
eventually end, but each job uses the ENDJOB delay
time.
** Group jobs
Group jobs all have the same user name.
If the default of ADLINTJOBS(*NONE) is used and the
group job that is active has the lock, it will be
ended. The next group job will then become active.
If the default of ADLINTJOBS(*NONE) is used and the
group that has the lock is not active, it will not be
ended until the user switches to that group job. If
the user switches to the job holding the lock, the job
will be ended after the ENDJOB DELAY limit has been
reached. If the user has gone home, the job will not
end.
If ADLINTJOBS(*ALL) is specified, all jobs will
eventually end.
SNDOBJLCKM escape messages you can monitor for
----------------------------------------------
TAA9891 No locks are held on any of the named objects.
TAA9892 Batch jobs retain locks
Sent if BCHESCMSG(*YES) is specified
Escape messages from based on functions will be re-sent.
SNDOBJLCKM Command parameters *CMD
-----------------------------
OBJ A list of up to 100 objects that will be checked.
This is a 3 part parameter of object, library, and
object type. The library value defaults to *LIBL.
A specific library or *CURLIB may also be used.
Only specific object types may be checked.
For example, a library, a data base file, or a data
area may be checked. For the complete list, use the
prompter. While *FILE is a valid type, locks cannot
be placed on certain file types such as a printer
file.
ACTION The action to be performed.
*CHECK is the default to provide a listing of the
jobs that would be sent a message. Using *CHECK
allows you to review what would happen if *SEND or
*ENDJOB were specified.
*SEND may be specified to send a string of text that
is specified in the MSG parameter. When *SEND is
used, the MSG parameter cannot be *NONE.
*ENDJOB may be specified to send a string of text
that is specified in the MSG parameter and then end
the job based on the ENDJOBWAIT and ADLINTJOBS
parameters. When *ENDJOB is used, the MSG parameter
cannot be *NONE.
MSG The text of the message to be sent as a break
message to workstations where jobs are holding locks
on one or more of the specified objects. Up to 256
bytes may be sent. The message is sent to the
workstation message queue. Only one message is sent
even if:
- Multiple objects are specified and a single job
holds more than one lock.
- Multiple jobs exist at the same workstation (eg
group jobs) and one or more jobs hold locks on one
of the specified locks.
The number of seconds to wait after sending a
message until the ENDJOB command is run. This
differs from the ENDJOB DELAY parameter.
The number of seconds to wait after ENDJOB is run
for a job before the job is cancelled abnormally.
The value is passed thru to the ENDJOB command DELAY
parameter. The wait time allows jobs that are
listening for a 'cancel' to cleanup properly.
Specifies whether additional interactive jobs
associated with the job being ended will also be
ended. The value is passed thru to the ENDJOB
command.
If you have multiple jobs at a workstation that you
are trying to end and the user has gone home, you
will probably need to specify *ALL. See the
discussion of 'Multiple Jobs at a Workstation' in
the tool documentation.
*NONE is the default meaning the additional jobs
will not be ended.
*GRPJOB may be specified to end any additional group
jobs.
*ALL may be specified to end all additional jobs.
This includes group jobs and secondary jobs.
A list of up to 100 job names that will be omitted
from receiving a message. If a job (either
interactive or batch) is named that holds a lock, it
will not appear as an exception.
The default is *NONE meaning, no job names are to be
omitted.
You may want to omit certain jobs you know will have
a lock that will be special cased by whatever action
you need to perform.
A list of up to 100 user names that will be omitted
from receiving a message. If a user is named that
holds a lock, it will not appear as an exception.
The default is *NONE meaning, no user names are to
be omitted.
You may want to use this to omit certain users you
know will have a lock that will be special cased by
whatever action you need to perform.
OUTPUT How to output the results. * is the default to
display the spooled file if the command is entered
interactively. The spooled file is deleted after it
is displayed.
If the command is entered in batch or *PRINT is
specified, the spooled file is output and retained.
BCHMSGQ Whether to send a message to a message queue if any
batch jobs hold a lock. *NONE is the default
meaning a message will not be sent.
A qualified name of a message queue may be entered
such as QSYSOPR in QSYS. If the library name is
blank, *LIBL will be used. A specific library name
or *CURLIB may be entered.
BCHESCMSG A *YES/*NO parameter for whether to send an escape
message if any batch jobs hold a lock.
*NO is the default to send only a completion
message.
*YES may be specified to cause the TAA9892 escape
message to be sent. This allows a time dependent
job to cause an action if batch jobs exist which
hold a lock.
Restrictions
------------
You must have *JOBCTL special authority to use SNDOBJLCKM.
Prerequisites
-------------
The following TAA Tools must be on your system:
CHKDUPLST Check duplicate list
CHKJOBCTL Check *JOBCTL special authority
CHKOBJ3 Check object 3
CVTOBJLCK Convert object lock
EDTVAR Edit variable
EXTLST Extract list
EXTLST2 Extract list 2
RSNLSTMSG Resend last message
RTVJOBA2 Retrieve job attributes 2
RTVSYSVAL3 Retrieve system value 3
SNDCOMPMSG Send completion message
SNDDIAGMSG Send diagnostic message
SNDESCINF Send escape information
SNDESCMSG Send escape message
SORTDBF Sort data base file
Implementation
--------------
None, the tool is ready to use.
Objects used by the tool
------------------------
Object Type Attribute Src member Src file
------ ---- --------- ---------- ----------
SNDOBJLCKM *CMD TAALICT QATTCMD
TAALICTC *PGM CLP TAALICTC QATTCL
TAALICTC2 *PGM CLP TAALICTC2 QATTCL
TAALICTR *PGM RPG TAALICTR QATTRPG
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