Interactive Sessions between Internal Servers not Responding

Updated May 18, 2018

Hello Experts,

My interactive sessions are not responding. There is an error during the RFC Communications. When I look in the system log, entries starting with the keys R36 or Q03 are found i.e.

“No WP Block Received”, or
“No APPC Block Received”, or
“No free block found in the WP communication Area”

Comments

26 Apr 2016 5:50 pm Sonia Barwar Helpful Answer

When communicating with internal servers, the system typically allocates memory in two shared areas. You can specify the parameters of the sizes of the memories using:
Rdisp/wp_ca_blk_no for wp_ca blocks, and
Rdisp/appc_ca_blk_no for appc_ca blocks.
By default, the sizes are 32048 bytes per wp_ca blocks and 34816 bytes per appc_ca blocks.
The error mentioned in the question indicates that any one of the two above mentioned memory sizes is too low. Upon increasing the allocation the error will vanish.
The decrease in parameter size might be a result of:
1.An increase in the number of users
2.An increase in the number of work processes
3.An increase in the number of RFC connections.

26 Apr 2016 5:50 pm Chandan Singh Parihar Helpful Answer

You can determine the memory required according to the following formulas:
rdisp/wp_ca_blk_no ~ rdisp/tm_max_no +

2 * (rdisp/wp_no_dia +
rdisp/wp_no_vb +
rdisp/wp_no_vb2 +
rdisp/wp_no_enq +
rdisp/wp_no_btc +
rdisp/wp_no_spo)
rdisp/appc_ca_blk_no ~ max(rdisp/tm_max_no, rdisp/max_comm_entries) +

2 * (rdisp/wp_no_dia +
rdisp/wp_no_vb +
rdisp/wp_no_vb2 +
rdisp/wp_no_enq +
rdisp/wp_no_btc +
rdisp/wp_no_spo)
To eliminate the problem, go to transaction SM51 and read do the following:
1.Select the internal server
2.Follow goto-> serverName-> Information -> WP-CA Blocks, or goto-> serverName -> Information -> APPC-CA Blocks
3.Set up the server properly and restart the server.