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.
Do not change the default setting of this parameter without consulting SAP first.
Value Range |
Unit |
Default Value |
32768-256K |
Bytes |
65536 |
mpi/total_size_MB
Parameter mpi/total_size_MB specifies in megabytes the total size of the shared memory area used for the MPIs.
Value Range |
Unit |
Default Value |
5-1000 |
Megabytes |
80 |
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.
Value Range |
Unit |
Default Value |
50-20500 |
MPIs |
4000 |
Additional Information
AS ABAP
SAP Web Dispatcher
Configuring SAP Web
Dispatcher for Large Number of Users