Real-time data processing exactly once (
) - the task is extremely non-trivial and requires a serious and thoughtful approach throughout the entire calculation chain. Some even believe that such a problem is impossible. . In reality, one wants to have an approach that ensures fault-tolerant processing in general without any delays and the use of various data stores, which puts forward even more stringent requirements for the system:
and the heterogeneity of the persistent layer. To date, this requirement does not support any of the existing systems.