1. A method comprising: determining a cost estimate for performing a first operation indicated in a first execution plan that is generated for a first query; while executing the first execution plan, determining an actual cost of performing the first operation; performing a comparison between the actual cost and the cost estimate; based on the comparison, storing object identification data that identifies one or more database objects that are associated with the first operation; identifying, within a second execution plan that is generated for a second query that is different than the first query, a second operation that is associated with the one or more database objects; in response to identifying the second operation that is associated with the one or more database objects, analyzing the object identification data to determine that the one or more database objects are associated with a previous operation; wherein the method is performed by one or more computing devices.