A distributed clock synchronization system is crucial for many applications, including distributed SQL databases, which require high availability and resilience to failures. The challenge lies in synchronizing time across nodes in a distributed system, where each node has its own notion of time that may not be synchronized with others. Various approaches have been proposed to address this issue, including Network Time Protocol (NTP), logical clocks, centralized timestamp oracles, distributed time synchronization using atomic clocks, and Hybrid Logical Clocks (HLC). Each approach has its strengths and weaknesses, and the choice of one over another depends on factors such as scalability, availability, and deployment constraints. The discussion highlights the importance of accurate time synchronization in ensuring the reliability and performance of distributed systems.