Systems and methods for providing resource isolation in a shared computing environment using reinforcement learning (RL) techniques are disclosed. A resource isolation mechanism may be applied in a shared storage system, or database service, that limits the resource utilization of each namespace to its specified allocation. For example, the mechanism may be used to limit the I/O utilization of database applications in a shared computing system to a specified limit, and may apply RL techniques, along with domain-specific constraints, to the system to automatically control the rate of queries made by an application. RL techniques, such as those based on the State-Action-Reward-State-Action (SARSA) method, may be effective in controlling resource utilization for different workloads, and may be enhanced by their application in conjunction with domain-specific business rules. RL techniques may be applied globally by the service, or may be applied to particular subscribers, applications, shared resources, namespaces, or query types.