Cost-based optimization and algebra-based execution for queries on XML data
Event details
| Date | 03.06.2013 |
| Hour | 14:00 › 15:00 |
| Speaker | Prof. Vasilis Vassalos, Athens University of Economics and Business |
| Location | |
| Category | Conferences - Seminars |
This talk will address the problem of optimization and execution of queries on XML data. We will discuss a complete, generic and modular XPath cost-based optimization and execution framework. The framework is based on a logical XPath algebra and a comprehensive set of rewriting rules that together enable us to algebraically capture many existing and novel processing strategies for XPath queries. Key pieces of the framework are the physical operators that are available to the execution engine, to turn queries into execution plans. Such operators, to be efficient, need to implement sophisticated algorithms for logical XPath or XQuery operations. Moreover, to enable a cost-based optimizer to choose among them correctly, it is also necessary to provide cost models for such operator implementations. We will present different families of algorithms for XPath physical operators, along with detailed cost model. We will present experimental evaluations of the performance of these operators over different XML storage engines. Another important part of the framework that we will discuss is an efficient cost-based plan selection algorithm for queries. Such a cost-based query optimizer is independent of the underlying physical data model and storage system and of the available logical operator implementations, depending on a set of well-defined APIs. Finally, to round out the presentation, we will also present an implementation of those APIs, including primitive access methods, the physical operators, statistics estimators and cost models.
Links
Practical information
- General public
- Free
Organizer
- SuRI 2013
Contact
- Simone Muller