With an increasing use of data mining tools and techniques, we envision that a Knowledge Discovery and Data Mining System (KDDMS) will have to support and optimize for the following scenarios: 1) Sequence of Queries: A user may analyze one or more datasets by issuing a sequence of related complex mining queries, and 2) Multiple Simultaneous Queries: Several users may be analyzing a set of datasets concurrently, and may issue related complex queries. This paper presents a systematic mechanism to optimize for the above cases, targetting the class of mining queries involving frequent pattern mining on one or multiple datasets. We present a system architecture and propose new algorithms for this purpose. We show the design of a knowledgeable cache which can store the past query results from queries on multiple datasets. We present algorithms which enable the use of the results stored in such a cache to further optimize multiple queries. We have implemented and evaluated our system with bo...