Memory Pipes

Data transfer between ICM (Internet Communication Manager) and the SAP work processes goes via memory pipes (MPI). These work on the basis of shared memory.

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. This parameter defines the size of these blocks.

Do not change the values of this parameter.

Value Range	Unit	Default Setting
32768-256K	Bytes	65536

mpi/total_size_MB

This parameter specifies in megabytes the total size of the shared memory area used for the MPIs.

Value Range	Unit	Default Setting
5-1000	Megabytes	40

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 Setting
50-20000	MPIs	4000