SAP
Application Dataflow in the Oracle Database
In SAP applications,
end-user requests are processed by the Oracle database as follows:
1. The end user logs into
the SAP system via the SAP front end and executes a business transaction.
2. The user request is
executed by the SAP dialog work process.
3. The Oracle server
detects the incoming call, accepts the call, and sets up a dedicated server
process.
4. There is a one-to-one
relationship between SAP work processes and Oracle server (shadow) processes.
5. The user runs the SQL statement and
commits the transaction.
6. The server process looks into the
shared pool of the Oracle Database for any reusable SQL.
7. If it finds a reusable SQL, then it
verifies authorization.
8. If it does not find reusable SQL,
then a new, shared SQL area is allocated and is parsed and processed.
9. The server process then retrieves
data from the SGA or the datafile.
10. The Oracle server process modifies
the data blocks in the SGA and, when efficient, the database writer writes the changes
permanently to the data files.
11. The log writer records committed
transactions to the online redo log files.
12. A reply is sent back to the user regarding the status
of the transaction call (success or error).
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