1. A computer-implemented method for a host controller system, the method comprising: maintaining, by the host controller system monitoring operation of a plurality of virtual machines, a list of a plurality of queries in association with a plurality of client devices, the plurality of queries specifying the plurality of virtual machines hosted by a plurality of host computers in a virtual machine system, the plurality of queries being continuously re-executed to refresh up-to-date information about the plurality of virtual machines that is presented on the plurality of client devices; receiving, by the host controller system, a new query from a first client device that is different from any of the plurality of client devices, the new query specifying one or more of the plurality of virtual machines; determining, by a processing device of the host controller system, whether the new query is similar to any of the plurality of queries previously received from the plurality of client devices other than the first client device, wherein the determining comprises comparing the one or more virtual machines in the new query to virtual machines in the plurality of queries previously received from the plurality of other client devices; if the new query is similar to any of the plurality of queries previously received from the plurality of other client devices, associating a similar query with the first client device in the list, and providing data pertaining to a result of a last execution of the similar query to the first client device; and if the new query is not similar to any of the plurality of queries previously received from the plurality of other client devices, adding the new query to the list in association with the first client device, executing the new query, and providing a result of an execution of the new query to the first client device, the result of the execution of the new query providing up-to-date information pertaining to operation of the one or more of the plurality of virtual machines in the virtual machine system.