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Remote Function Call (RFC) in SAP

RFC is an SAP protocol to handle communications between systems which simplifies the programming. A remote function call (RFC) is the call of a function module that runs in a different system to the calling program. It is also possible to call a function module in the same system as an RFC; normally RFCs are used when the caller and the called function module run in different systems. In the SAP system, these functions are provided by the RFC interface system. The RFC interface system enables function calls between two SAP systems, or between an SAP system and an external system. RFCs manage
1) Communication process
2) Parameter transfer
3) Errors.
RFC describes an interface to call the function. In RFC communications between two SAP systems, the calling system uses an RFC definition in the target system to access a specific function. The destination of an rfc call might be R/2 connection, R/3 connection, internal connections, logical connections (like to logical systems) or TCP/IP (external systems) connections.
There are five types of RFCs in SAP
1) Synchronous RFC (sRFC)
It requires that the target system is active when the RFC is made. This type of rfc is used for communication between different systems and between SAP Web AS and SAP GUI.
2) Asynchronous RFC (aRFC)
It doesn’t require the target system to be active when RFC is made. This is used for parallel processing jobs and for communication between different systems.
3) Transactional RFC (tRFC)
This is a variation of aRFC. The transactions are divided into steps and are processes step by step. This is an asynchronous transaction. This is helpful in scenarios where there is probability of network failure between the systems.
4) Queued RFC (qRFC)
This is a variation of tRFC. Here the individual steps are executed sequentially.
5) FastRFC

This is used for system internal communications. Interactions between J2ee engine in sap & the abap runtime environment in the same instance are done using these RFC. This type of RFC is possible only if both the source & target are on the same system.
The RFCs are managed using t-code sm59
Use t-code SMT1 to manage trusted systems

Archive (ARCH) copies the on-line redo log files to archival storage when they are full. ARCH is active only when a database redo log is used in ARCHIVELOG mode.

The primary function of the redo log is to record all the changes made to data. Changes made to entries are written to the on-line redo log files. So that they can be used in roll forward operations during database recovery.
When a change has happened, the entry will be first stored in the SGA. SGA has the following components:
1. Shared pool
2. Database buffer cache (DB cache)
3. Redolog Buffer
4. Large pool
5. Java Pool

Shared pool, consists of shared SQL area and shared PL/SQL area. DB cache will have the most recently used blocks & the blocks that needs to be written to the datafile. Redolog Buffer contains the changed/redo data and Large pool is used only in parallel sever environment.
The SGA may also use a Java pool, if java stored procedures are used.
When a SQL statement is executed, the output (data) will be stored in these DB cache as dirty blocks, and then moved into redo log buffers, which will be updated at a later stage.

RFC is an SAP protocol to handle communications between systems which simplifies the programming. A remote function call (RFC) is the call of a function module that runs in a different system to the calling program. It is also possible to call a function module in the same system as an RFC; normally RFCs are used when the caller and the called function module run in different systems. In the SAP system, these functions are provided by the RFC interface system. The RFC interface system enables function calls between two SAP systems, or between an SAP system and an external system. RFCs manage

1) Communication process

2) Parameter transfer

3) Errors.

RFC describes an interface to call the function. In RFC communications between two SAP systems, the calling system uses an RFC definition in the target system to access a specific function. The destination of an rfc call might be R/2 connection, R/3 connection, internal connections, logical connections (like to logical systems) or TCP/IP (external systems) connections.

There are five types of RFCs in SAP

1) Synchronous RFC (sRFC)

It requires that the target system is active when the RFC is made. This type of rfc is used for communication between different systems and between SAP Web AS and SAP GUI.

2) Asynchronous RFC (aRFC)

It doesn’t require the target system to be active when RFC is made. This is used for parallel processing jobs and for communication between different systems.

3) Transactional RFC (tRFC)

This is a variation of aRFC. The transactions are divided into steps and are processes step by step. This is an asynchronous transaction. This is helpful in scenarios where there is probability of network failure between the systems.

4) Queued RFC (qRFC)

This is a variation of tRFC. Here the individual steps are executed sequentially.

5) FastRFC

This is used for system internal communications. Interactions between J2ee engine in sap & the abap runtime environment in the same instance are done using these RFC. This type of RFC is possible only if both the source & target are on the same system.

The RFCs are managed using t-code sm59

Keyword: SAP HR
Title : Useful function modules in ABAP-HR