Memory shared means Remote CHA with only EJB support.
The memory shared CHA is a sub-set of the whole CHA architecture. In the memory shared CHA, CHAInstance CMP bean and the database are excluded from the CHA architecture. The context persistence feature is not used.
To the local contexts, there is no difference between memory shared CHA and persistence shared CHA. But for remote contexts, there are differences: remote contexts under the memory shared CHA always stay in the singleton memory cache during their lifecycles, and they will never be stored into the database.
Access to the database is very time-consuming and always impacts the performance of BTT application. Therefore, to remove the database dependency and to keep all the runtime data in memory can guarantee good performance of the BTT applications, especially CHA performance.
<kColl id="cha-server"> ... <field id="startMode" value="MemoryShared"/> ... </kColl>
Furthermore, the function of "cleanupCHAServer" is disabled under memory shared CHA.