1. Dialog work process for online users.
2. Background work process for background users.
3. Update work process upd and up2(Critical and less critical)
4. Spool work process (printer)
5. En queue work process ( leader)
Dialog Work process (DIA):
· Dialog work process is responsible for online job.
· Each Dialog work process is allotted with specific time for executing the given command.
· All interactive request (SAPGUI) will be processed by Dialog work process.
· We can request the processing time of a dialog work process within the help of profile parameter (t code is RZ10)
· Each work process required 50-60 MB of memory.
· Work process count: we need to modifying profile parameter “rdisp/wp_no_dia”.
· Dialog timeout: we need to modifying profile parameter “rdisp/max_wprun_time”. Default is 600 seconds
Background Work process (BTC):
According to SAP Standards each dialogue work process can hold 10 users. But one at a time.
· At least two dialogue work process per instance.
· You can define any number of background work process jobs. All this jobs will be executed one by one with this background work process.
· Each background work process will process on background job at a time. While processing a background job.
· The background work process process will internally use one or more than one dialog work process. Background jobs are defined in 3 classes.
*i) *Class A (High priority)
*ii) *Class B (Medium priority)
*iii) *Class C (Low priority)
· The parameter for background work process are “rdisp/wp_no_btc”
Spool Workprocess (SPO):
· It is meant for print related tasks in sap environment.
· There will be at least one spool process for whole SAP system.
· The parameter for Spool work process is “rdisp/wp_no_spo”
Update Work process (upd and up2):
· These are 2 types Critical and less Critical
· These are represented as upd and up2 respectively and also as V1 and V2 respectively.
· Upd is synchronous update (offline) Ex: E-mail
· Upd2 is synchronous update (online) EX: ATM
· Update work process is nothing but save data in database.
· The parameter for update work process is “rdisp/wp_no_vb”
En queue Work process:
· En queue is responsible for lock management and to send request in queue.
· En queue resides in central instance.
· This will avoid modifying a particular table by two different users parallel. There are two major types of Locks.
i) Shared Lock: When users “A” then all other users can read the table “A”, but cannot modify it until user “A” finished it.
ii) Exclusive Lock (X): When User “A” access table “A” and nobody can also read or dispatching “A” until user “A” finished it. All this information will be written to lock table that was created in Central Instance shared memory are at the time of Instance start. This size of this table is 4 MB by default and the maximum size you can define is 100 MB.
· When locks are occurring in peak time there are may be lock overflow errors of you see this error regularly.
· These are mush change size of lock table. There will be also on En queue work process for whole SAP system it can be changed to more than one when SAP support recommends.
· The parameter for En queue work process is “rdisp/wp_no_enq”
· Group of R/s services (Dialog, background, Update, En queue and Spool).
Ø It all the Work process types are the dialog in application server then it is called as Dialog instance.
Ø A Central Instance comprises all the four types of Work process, Gateway and Message services.
Ø Gateway is common for the entire Instance.
Ø Message Service only on in the Central Instance.
Ø The moment we load database Instance we are going to get all the modules of SAP.