Oracle instance question

[Former Member]

Hello All,

When we start oracle instance, background processes are started.

SAP wp connect to the shadow work processes.Now when these shadow work processes are created?

During oracle instance startup or when sap work processes reuqested a connection?

Regards,

Tushar

[Former Member]

Hi,

When a SAP work process makes a connection request to the database, the dedicated shadow process is created by the listener. Then all the database requests are handled by the respective shadow work process.

With regards

Sudha

[stefan_koehler]

Hello Tushar,

the startup has 3 steps.

1) STARTUP NOUMOUNT;

Only the instance is started. The SGA is allocated and the DBWR, PMON, SMON and LGWR process is started. No control files or data files are touched.

2) STARTUP MOUNT;

The instance is started and the control file is accessible through the DBWR. You can add, drop, rename datafiles...change the archivelog mode, etc...

3) STARTUP;

Normal startup... the instance is started and all files are accessible.

>> Now when these shadow work processes are created? During oracle instance startup or when sap work processes reuqested a connection?

The shadow processes are created, if you want to create a connection to the oracle database. In the SAP environment , the work process is connecting through OracleNet (Listener) and the listener is creating one shadow process and mapping the request to it.

For more information have a look here:

http://download.oracle.com/docs/cd/B19306_01/server.102/b14220/process.htm#i16565

Regards

Stefan