How to Increase HTTP Security Context If Cache is full?
When we launch the HTTP Security Session Monitor (transaction SM05), we are getting the message "HTTP Security context cache is full" in the system log (transaction SM21).
You can use transaction SICF_SESSIONS to activate or deactivate the HTTP security session management for each logical system. When you see this error it means that HTTP security session management is active on this system.
However you have reached the threshold for the maximum number of security contexts / cache entries as controlled by parameter http/security_context_cache_size.
If you are encountering this error specifically with regard to stateless HTTP connections to the ICF service /sap/xi/ please ensure that you have reviewed and implemented SAP 2036846 "Secure session cookie is featured at Process Integration (XI) Requests" (relevant for systems on SAP_BASIS 740 and 804).
You can resolve this problem by following 2 ways :
Increase the maximum number of security contexts / cache entries which are permitted by increasing the parameter http/security_context_cache_size
and / or
Reduce the lifetime of the cache entries by lowering the parameter http/security_session_timeout