Parameters for Memory Pipes

Data is transferred between ICM (Internet Communication Manager) and the SAP work processes in AS ABAP using Memory Pipes (MPI). These are structures based on the shared memory. The MPI interface is also used for communication between AS Java (Java Dispatcher) and ICM, and between the Web Dispatcher and ICM.

The following parameters relating to memory pipes are provided:

mpi/buffer_size

Data transfer within memory pipes is conducted in blocks of a set length (“MPI buffers”). Parameter mpi/buffer_size defines the size of these blocks.

Caution Caution

Do not change the default setting of this parameter without consulting SAP first.

End of the caution.

Domain	Unit	Default Value
`32768`-`256K`	Bytes	`65536`

mpi/total_size_MB

Parameter mpi/total_size_MBspecifies in megabytes the total size of the shared memory area used for the MPIs.

Domain	Unit	Default Value
`5`-`1000`	Megabytes	`80`

Recommendation

On 64 bit platforms SAP recommends a value of 400.

End of the recommendation.

mpi/max_pipes

The parameter specifies the maximum number of memory pipes.

Two memory pipes are required for each HTTP connection.

The default setting only has to be changed for very big systems or for the Web Dispatcher that has to keep open a lot of parallel connections.

Domain	Unit	Default Value
`50`-`20500`	MPIs	`4000`

More Information

Memory Pipes and MPI Buffers

AS ABAP:

icm/wp_mpi_available

icm/wp_roll_timeout

SAP Web Dispatcher:

Configuring SAP Web Dispatcher for Large Number of Users