Event Sourcing (ES) systems use an event log with the double purpose of keeping application state and providing decoupled communication. While ES systems keep track of all business events, other untracked events, either from internal components or from external systems may still cause failures. Determining the root cause of such failures usually involves complex procedures based on replaying the event log. Unlike this, in distributed systems, developers often instrument the source code, for the sake of improving observability and perform tracing on workflows and data.

Adding tracing to ES thus seems like an unexplored and powerful approach to improve the observability of the system. In this paper, we suggest possible implementations of the idea and discuss their merits. These include the adoption of well-known tracing-related tools and standards in ES systems, with the respective advantages for root-cause analysis, anomaly detection, profiling and others.

事件溯源 (ES) 系统使用事件日志具有保持应用程序状态和提供解耦通信的双重目的。尽管 ES 系统会跟踪所有业务事件，但来自内部组件或外部系统的其他未跟踪事件仍可能导致故障。确定此类故障的根本原因通常涉及基于重放事件日志的复杂过程。与此不同的是，在分布式系统中，开发人员通常会检测源代码，以提高可观察性并对工作流和数据进行跟踪。

因此，向 ES 添加跟踪似乎是一种未经探索的强大方法，可以提高系统的可观察性。在本文中，我们提出了该想法的可能实施方案并讨论了它们的优点。其中包括在 ES 系统中采用众所周知的跟踪相关工具和标准，在根本原因分析、异常检测、分析等方面具有各自的优势。