Towards Designing An Execution Control System with Metastability Resilience
Modern databases must serve highly variable workloads: short queries that demand low latency and long-running tasks that consume significant resources. Under heavy load, these workloads risk spiraling into metastability, a self-sustaining state of degraded throughput and high latency that persists even after the initial stressor is removed. In this paper, we investigate the design of an Execution Control System (ECS) specifically engineered for metastability resilience.To explore this design space, we developed MESSI, a discrete-event simulator implemented in Go that enables us to replay stress scenarios, visualize the formation of metastable feedback loops, and quantify resource allocation trade-offs. By representing systems as a graph of Logic Nodes and Processors, MESSI captures queueing dynamics, I/O delays, and retry policies at a fine grained level. Our research highlights how conventional management policies can inadvertently trigger metastable failures and demonstrates that principled load shedding and bounded concurrency (via a ticket-based abstraction) are essential for maintaining responsiveness. Our findings provide a roadmap for building performant and predictable ECS that explicitly operate within a safe resilient envelope even under dynamically shifting workloads.