In system log (transaction SM21) you see the error 'Kernel error:ICM_HTTP_CONNECTION_FAILED (400)'
In BW720 - BW730 landscape, BWA uses ICM as a communication method for aggregates (i.e. query execution) as a default. If the communication between ICM and TREXIndexServer has an issue, BW query execution fails with the following error;
Remote communication failure with partner
http://<host name>:<TREXIndexserver port>/asxml/olapCellSearch/TREX internal error. Please contact SAP for further analysis (status code = 400).
And in ICM trace (TA:SMICM -> Goto -> Trace File -> Display All) you find the following error;
trace level (1 = Default)
"** WARNING => Connection request from (45/5815/0) to host: <host name>, service:<TREXIndexServer port> failed (NIECONN_REFUSED)
trace level (2 = Full Trace)
NiIGetHostName: addr <IP address of the host> = hostname <host name>
*** ERROR => NiBufIConnect: non-buffered connect pending after 5000ms (hdl 203;<host name> :<TREXIndexServer port>) [nibuf.cpp 4669]
NiICloseHandle: called for hdl 203 while waiting for connection
NiICloseHandle: shutdown and close hdl 203/sock 47
*** WARNING => Connection request from (125/1101/0) to host: <host name>, service: <TREXIndexServer port> failed (NIECONN_REFUSED)
ICM, ICM_HTTP_CONNECTION_FAILED, NIECONN_REFUSED, ifconfig, SM21, system log
- If ICM connection test fails even when BWA is not accessed, please check the configuration as per SAP notes 1501222 (Solution 2 - 4), 1739876
- Check if using IP address from host name (and vice versa) works. If using IP address ICM has no issue, please check DNS server.
To change the setting from host name to IP address, please go to TREXADMIN and click TREX ABAP Customizing and select 'Use IP address instead of hostname'
When an ICM problem occurs during a query execution, DB failover can be triggered if you configure an email address and BWA becomes unavailable for 30 min. If you do not want it to happen because the connection test already shows green soon after the problem occurred, you can make BWA down time shorter by removing the entry from the table RSDDTREXHPAFAIL as per SAP note 1512510.