Technologies are described for facilitating the processing of requests for database operations within a database environment that includes one or more processing units and a memory. A utilization level of one or more computing resources of a database system is periodically determined. When a request for a database operation is received from a database client, it is determined, such as based on the utilization level, whether the database system has sufficient resources to process the request. If the database system does not have sufficient resources to process the request, the request is enqueued in a request queue for deferred execution. If it is later determined that the database system has sufficient resources to execute the request, the request can be dequeued, executed, and execution results returned to the database client.