Anatomy of a Throttler, part 1

This post introduces the concept of a throttler for database systems, focusing on asynchronous, batch, and massive operations. It discusses various metrics for determining when to throttle, including replication lag, threads_running, queue delay, queue length, load average, and pool usage. The post emphasizes the importance of using multiple metrics and understanding their limitations as symptoms rather than direct causes. It also touches on how introducing a throttler can reveal existing synchronization issues in applications.