As senior engineers evaluating open-source time-series databases, a comparison of openGemini and TDengine reveals distinct profiles in momentum, community size, and use cases. OpenGemini, a CNCF sandbox project, boasts 1,146 stars and a modest 7 stars in the last 30 days, indicating a smaller, potentially more niche community. In contrast, TDengine stands out with 24,791 stars and 78 stars in the last 30 days, showcasing significantly higher momentum and a larger, more actively engaged community. The use case focus also diverges: openGemini is positioned as a general-purpose distributed time-series database emphasizing high concurrency, performance, and scalability, suitable for a broad range of applications. TDengine, however, is specifically designed for Industrial IoT (IIoT) scenarios, tailoring its high-performance and scalability features to the unique demands of IoT environments. While openGemini's versatility might appeal to developers seeking a generalized solution, TDengine's targeted approach could offer optimized performance for IIoT-focused projects. Both projects cater to distinct needs, reflecting their differing community dynamics and design centers. Engineers should align their choice with the specific requirements of their project, considering both the technical fit and the community support landscape.