Even though the Work processes are unique at OS level SAP differentiated between the work processes based on the basis architectured nature of work.
The process are determined by the instance name DVEBMGS<Instance_No>
For Dialogue instances the work process will be denoted as D01, D02….
Work process Categories
- D – Dialogue
- V – Update
- E – Enqueue
- B – Back ground
- M – Message
- G – Gateway
- S – Spool
1. DIALOGUE ‘D’
It is only the process which communicates interactively with the users. There should be atleast 2 Dialogue work process per instance. Dialogue work process initiates Update, Background and Spool.
2. UPDATE ‘V’
It is used to update the transactions in the database. It is initiated by Dialogue process. There should be atleast 1 Update process in the entire system. It is also recommended to have an update process for every 5 Dialogue.
3. ENQUEUE ‘E’
It is used to provide locks for the records that are going to be updated. It ensures consistency for updates. There will be only 1 Enqueue configured in the system during the installation. It is possible to have more than one enqueue provided they are installed or configured on the central instance.
4. BACKGROUND ‘B’
The tasks which are expensive or time consuming are scheduled to run in the background mode non-interactively. There should be atleast 2 background work process in the system
5. MESSAGE ‘M’
There should be only 1 message server in the entire R/3 system. It is used to manage all the dispatchers. It is used to load balance the requests to identify the least loaded dispatcher.
It is also used to provide locks to the request that are coming from Dialogue instances.
7. SPOOL ‘S’
It is used to print the documents to a printer or output to a fax machine etc. There should be atleast 1 Spool process in the entire system. It is also possible to configure more spool process depending on the print/ spool volume.
SMGW is used to monitor the gateway process. Gateway is used to communicate between SAP and NON-SAP systems. There will be only 1 gateway/ instance. If required we can also install a standalone gateway on a JAVA engine. Gateway listens on port ‘3300’+instance number (3300, 3301,3302 where 01, 02 are the instances). Gateway provides an interface so that the external system can communicate with SAP system on the specified port. When RFC’s are defined between the systems they use SAP gateway when (ALE, EDI, IDOC are transferring they use gateway)