A review of different cost-based distributed query optimizers

The paper narrates the review of cost-based query optimizers designed using database strategies, deterministic, stochastic, hybrid and energy efficiency-based techniques. It was endowed that earlier authors have used a different database and deterministic strategy like indexing, query filtering, normalization, query graph, tableau, exhaustive enumeration, query graph and dynamic programming to optimize queries. However, these techniques are not pertinent to the optimization of serpentine database queries. Nonetheless, it can be resourcefully optimized by using divergent individual and hybrid nature-inspired computing techniques. Research divulges that the hybrid approach was and remains effective to unravel the query optimization problem. Moreover, notable work is effectuated to optimize data retrieval queries only; however, little work is carried out to optimize write, delete and update queries. Additionally, energy-efficient query optimization is an emanate area. The copious amount of energy can be defended by using energy-efficient query optimizers. The extensive publication trend of distributed query optimizers has also examined that can be of enormous concern for the researchers who want to publish their article and to pursue their research in this domain area. It is ascertained that momentous volume of query optimization work has been effectuated using genetic algorithm followed by swarm particle optimization. Additionally, the researcher has to use and analyze the performance of different emerging evolutionary techniques (Ant Lion Optimization, Whale Optimization, Monkey Search, Dolphin Echolocation, Chaotic Swarming) in designing cost-based query optimizer.