One of the major challenges being faced by Database managers today is to manage the performance of complex SQL queries which are dynamic in nature. Since it is not possible to tune each and every query because of its dynamic nature, there is a definite possibility that these queries may cause serious database performance issues if left alone. Conventional indexes are useful only for those queries which are frequently executed or those columns which are frequently joined in SQL queries. This proposal is regarding a method, a query optimizer for optimizing database queries in a database management system. Just In Time(JIT) indexes are On Demand, temporary indexes created on the fly based on current needs so that they would be able to satisfy any kind of queries. JIT indexes are created only when the configured threshold values for resource consumption are exceeded for a query. JIT indexes will be stored in a temporary basis and will get replaced by new JIT indexes in course of time. The proposal is substantiated with the help of experimental programs and with various test cases. The idea of parallel programming is also brought into picture as it can be effectively used in a multiprocessor system. Multiple threads are employed while one set of threads proceed in the conventional way and the other set of threads proceed with the proposed way. A live switch over is made when a suitable stage is reached and from then onwards the proposed method will only come into picture.