Review Paper for Query Optimization for Declarative Crowdsourcing System
Nilesh Nivrutti Thorat, A. B. Rajmane
Crowdsourcing, query optimization, human intelligence tasks (HIT), Monetary cost.
Main goal of declarative crowdsourcing system is to keep out of sight the complexities of the system. In crowdsourcing system data is placed at different web or data servers therefore optimization of query has major challenge. To address some queries we need to add more information to that queries that machines cannot solve. SQL query is being submitted by user which is being optimized on cost constraint depending on which execution plan is created, output is produced. The proposed system can be used for answering declarative queries posed over stored relational data together with data obtained on demand from the crowd. The proposed system is based on cost-based query optimization for crowdsourcing system, which also consider the latency that generates best possible and suitable query execution plan. It supports three types of query evaluation: select, join, complex-join, having three algorithm for each operation respectively.