A query is received in a distributed storage system that asks for frequently accessed items of a select storage tier in a service store. The query is executed on at least one data summary structure maintained by a client node that corresponds with the select storage tier in the service store. Each data summary structure maintained by the client node summarizes a data stream of item access of the select storage tier during a period of time and different data summary structures from different periods of time are periodically merged so that the query is conducted on a merged data summary structure maintained by the client node. A result is returned from the executed query that is indicative of frequently accessed items of the select storage tier in the service store.