Optimization of multi-domain queries on the web
Proceedings of the VLDB Endowment
Chapter 10: join methods and query optimization
Search Computing
Information exploration in search computing
Search computing
Run-time adaptivity for search computing
Search computing
Tools supporting search computing application development
Search computing
The anatomy of a multi-domain search infrastructure
ICWE'11 Proceedings of the 11th international conference on Web engineering
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This chapter gives a high-level overview of how query processing is carried out in SeCo. At the highest level of abstraction, queries are expressed in a conjunctive declarative query language over service interfaces, named SeCoQL, chosen to be a compact and readable formulation to serve both experts users and system developers. Queries are then expressed at a logical level in the form of acyclic invocation workflows, after a compile-time analysis that decides a cost-driven scheduling of service invocations. At a lower, physical level queries are then translated into executable specifications that distinguish between the data flow and the control flow, support parallelism, account for stateless and stateful computation tasks, and support backward and forward control. The query engine is implemented as an interpreter of these physical plans. A workbench and testing environment is also available in the form of a tool, to monitor the processing of complex queries by inspecting all phases of their analysis and execution, at all levels of abstraction.