Is There a Method to Block Concurrent Requests From Running?

Yes. From the manager work shift, by making the processes=0 for that work shift at specific time and date.

Something to remember when creating manager work shifts that:

A. Date-specific work shifts override work shifts that do not specify a specific date.
B. Overlapping Work Shifts - Priority Levels:

1. The work shift with the more specific time period takes effect for the overlapping time period.

2. Overlapping work shifts with the same priority:

The work shift with the largest target processes takes effect.

How to Apply an 11i Patch When adpatch is Already Running

Adpatch is running and fails on one of the workers. To fix this worker andcontinue with the patch installation, a new patch needs to be applied. But only 1 adpatch session can run on an instance at any giventime, The following work around can be used to apply a patch when adpatch is already running.

1. Using the adctrl utility, shutdown the workers.
a. adctrl
b. Select option

3 "Tell worker to shutdown/quit"

2. Backup the FND_INSTALL_PROCESSES table which is owned by the APPLSYS schema
a. sqlplus applsys/
b. create table fnd_Install_processes_back as select * from fnd_Install_processes;
c. The 2 tables should have the same number of records.
select count(*) from fnd_Install_processes_back;
select count(*) from fnd_Install_processes;

3. Backup the AD_DEFERRED_JOBS table.
a. sqlplus applsys/
b. create table AD_DEFERRED_JOBS_back as select * from AD_DEFERRED_JOBS;
c. The 2 tables should have the same number of records.
select count(*) from AD_DEFERRED_JOBS_back;
select count(*) from AD_DEFERRED_JOBS;

4. Backup the .rf9 files located in $APPL_TOP/admin//restart directory.
At this point, the adpatch session should have ended and the cursor should be back at the Unix prompt.
a. cd $APPL_TOP/admin/
b. mv restart restart_back
c. mkdir restart

5. Drop the FND_INSTALL_PROCESSES table and the AD_DEFERRED_JOBS table.
a. sqlplus applsys/
b. drop table FND_INSTALL_PROCESSES;
c. drop table AD_DEFERRED_JOBS;

6. Apply the new patch.

7. Restore the .rf9 files located in $APPL_TOP/admin//restart_back directory.
a. cd $APPL_TOP/admin/
b. mv restart restart_
c. mv restart_back restart

8. Restore the FND_INSTALL_PROCESSES table which is owned by the APPLSYS schema.
a. sqlplus applsys/
b. create table fnd_Install_processes as select * from fnd_Install_processes_back;
c. The 2 tables should have the same number of records.
select count(*) from fnd_Install_processes;
select count(*) from fnd_Install_processes_back;

9. Restore the AD_DEFERRED_JOBS table.
a. sqlplus applsys/
b. create table AD_DEFERRED_JOBS as select * from AD_DEFERRED_JOBS_back;
c. The 2 tables should have the same number of records.
select count(*) from AD_DEFERRED_JOBS_back;
select count(*) from AD_DEFERRED_JOBS;

10. Re-create synonyms
a. sqlplus apps/apps
b. create synonym AD_DEFERRED_JOBS for APPLSYS.AD_DEFERRED_JOBS;
c. create synonym FND_INSTALL_PROCESSES FOR APPLSYS.FND_INSTALL_PROCESSES;

11. Start adpatch, it will resume where it stopped previously.