ENGINEERING OF SOFTWARE SYSTEMS BASED ON SNAPSHOT-CENTRIC CQRS WITH EVENT SOURCING ARCHITECTURE

Background. Command Query Responsibility Segregation (CQRS) with Event Sourcing (ES) is a widely adopted solution for designing scalable and high-performance information systems. However, classical CQRS with ES implementations are often associated with increased complexity in development and maintenance. Objective. The goal of this study is to simplify the development and maintenance of software systems built on CQRS with ES by introducing an alternative variation of the architecture. Methods. The classical architectural variation was analyzed, and the components that increase the complexity of system development and maintenance were identified. Based on this analysis, an alternative architectural variation (mCQRS) is proposed, that uses a lower-complexity component set. The solution is based on a relational database in which aggregate state snapshots are treated as the source of truth, thereby reducing implementation and maintenance complexity and facilitating potential migration to other architectural variations. Results. Representative test projects were developed for both the classical and the proposed CQRS with ES variations. Cyclomatic complexity values for a typical command execution workflow (120 for Classical CQRS and 82 for mCQRS) indicate a 31.67% decrease in complexity. Performance measurements show that server response time for queries is identical for both variations (44 ms), whereas the end-to-end time to reach system consistency for commands is 268 ms for Classical CQRS and 347 ms for mCQRS, corresponding to a 22.76% decrease in performance. Despite this degradation, write-operation throughput remains high in the context of established industry practices. Conclusions. The proposed approach improves the efficiency of development and maintenance and reduces the required level of developer expertise; it is suitable for systems in which write-operation performance is not critical