Initializing the DBQueue Processor

Initializing the DBQueue Processor

DBQueue Processor initialization takes place once during schema installation. The following database schedules are generated during the initialization phase:

• QBM_PWatchDog on <database>

  This database schedule assumes several functions in the One Identity Manager.

  • It checks whether DBQueue Processor's central dispatcher is active and restarts it.
  • It starts a database schedule to remove complete processes from the DBQueue.
  • It controls validation and starting of schedules.
  • It checks at regular intervals, whether database single-user mode is still required and resets the setting if necessary.

  This database schedule has an active schedule with a 1 minute interval.

• QBM_PDBQueueProcess_Main on <database>

  This database schedule is the DBQueue Processor's central dispatcher. The central dispatcher assumes control of processing and distributes DBQueue tasks to individual slots. Each time the central dispatcher is executed, the number of currently available slots required for the current run is found. The central dispatcher starts database schedules for the currently available slots just once.

  Only one database schedule at most is started for the central dispatcher. The central dispatcher's database schedule does not have an active schedule, but is started by the database schedule QBM_PWatchDog on <database>.

• QBM_PDBQueueProcess<SlotNumber> on <database>

  The maximum number of available slots is determined during the DBQueue Processor initialization phase. The maximum number of slots depends on the number of processors on the database server. An associated database schedule QBM_PDBQueueProcess<SlotNumber> on <database> is set up for each slot. Each database schedule is set up with a process which executes the DBQueue tasks for exactly this slot. The database schedules associated to each slot do not have any active schedules. They are started by the central dispatcher.

• QBM_PDBQueueProcess_Del on database

  This database schedule removes processed DBQueue tasks. The database schedule does not have an active schedule, but is started through the database schedule QBM_PWatchDog on <database>.

Related Topics

• DBQueue Processor Reinitialization

DBQueue Processor Reinitialization

DBQueue Processor Reinitialization

• You must execute the procedure QBM_PDBQueuePrepare once manually when the server hardware has been extended or custom DBQueue Processor tasks have been created.
• You must execute the procedures QBM_PDBQueuePrepare and QBM_PWatchDogPrepare once when you set up a reference database for test and development.

Run the following procedures once in the reference database using a suitable query tool.

SQL Server

exec QBM_PWatchDogPrepare

exec QBM_PDBQueuePrepare 0,1

Oracle Database

exec QBM_GWATCHDOG.PPREPARE(0);

exec QBM_GDBQUEUE.PDBQUEUEPREPARE(0);

Controlling Processing of DBQueue Processor Tasks

Controlling Processing of DBQueue Processor Tasks

The database schedule for the central dispatcher is started with the database schedule QBM_PWatchDog on <database> . The central dispatcher assumes control of processing and distributes DBQueue tasks to individual slots.

Each time the central dispatcher is executed, the number of currently available slots required for the current run is found first. The more load there is on the database, the less slots there are to use. At least two slots are used.

The number of currently available slots results from:

The number of currently available slots = maximum number of available slots - sum of all own database processes - sum of processes of other databases on the server

The central dispatcher starts database schedules for the currently available slots just once. Each database schedule is set up with a process , which executes tasks for exactly this slot.

Once tasks in the DBQueue are entered, the central dispatcher is notified. The central dispatcher distributes tasks to individual slots and notifies the slot processes that there are tasks are waiting to be processed. Each process processes the tasks queued for its slot. Once the task is complete, each process sends a message to the central dispatcher and waits for new tasks.

The central dispatcher checks at defined intervals whether the slots are still active and distributes new tasks to them. If there are no more tasks in the DBQueue, the central dispatcher goes into a wait state and waits for new task notifications.

Tasks on slots currently in use are still processed when the timeout expires. Then the slot database schedules are stopped and the central dispatches exits. For more information, see How the Central Dispatcher Communicates with Individual Slots.

Figure 66: Controlling Processing

Processing DBQueue Processor Tasks

Processing DBQueue Processor Tasks

The central dispatcher finds entries in the DBQueue (table DialogDBQueue) and moves the tasks into the table QBMDBQueueCurrent with the assignment tasks per slot.

Example of Entries in the Tables DialogDBQueue and QBMDBQueueCurrent

Each process processes tasks queued for its own slot in the table QBMDBQueueCurrent. Subsequent tasks resulting from processing are queued in the table DialogDBQueue.

When a process has handled its tasks and no new task are pending, process sets the slot number itself to "0" in the table QBMDBQueueCurrent. The entry initially remains in the table QBMDBQueueCurrent but is no longer taken into account (because slot 0 is not active).

The database schedule QBM_PDBQueueProcess_Del on <database> deletes all entries with slot number "0" from the table QBMDBQueueCurrent in regular intervals.

Related Topics

• Reactivating DBQueue Processor Tasks