1. A computer-implemented method for optimizing query performance in a relational database management system, comprising: receiving, by a processor, a query at the relational database management system; determining, by the processor, whether the query is expected to be a long-running query; in response to determining that the query is expected to be a long-running query, starting, by the processor, a full table scan to fetch records needed to satisfy the query from the relational database management system; in parallel with conducting the full table scan, building, by the processor, a performance object capable of satisfying the query in the relational database management system; in response to completing the construction of the performance object prior to completing the full table scan, stopping the full table scan and using the newly built performance object instead to satisfy the query; and storing the performance object in storage or memory for a predetermined time period.