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SUMMARY:Cost-based optimization and algebra-based execution for queries on
  XML data
DTSTART:20130603T140000
DTEND:20130603T150000
DTSTAMP:20260407T224608Z
UID:ec17fec8e80268c3fc52b491ccc27189c2d9d8081b4f83ae70971f58
CATEGORIES:Conferences - Seminars
DESCRIPTION:Prof. Vasilis Vassalos\, Athens University of Economics and Bu
 siness\nThis talk will address the problem of optimization and execution o
 f queries on XML data. We will discuss a complete\, generic and modular XP
 ath cost-based optimization and execution framework. The framework is base
 d on a logical XPath algebra and a comprehensive set of rewriting rules th
 at together enable us to algebraically capture many existing and novel pro
 cessing strategies for XPath queries. Key pieces of the framework are the 
 physical operators that are available to the execution engine\, to turn qu
 eries into execution plans. Such operators\, to be efficient\, need to imp
 lement sophisticated algorithms for logical XPath or XQuery operations. Mo
 reover\, to enable a cost-based optimizer to choose among them correctly\,
  it is also necessary to provide cost models for such operator implementat
 ions. We will present different families of algorithms for XPath physical 
 operators\, along with detailed cost model. We will present experimental e
 valuations of the performance of these operators over different XML storag
 e engines. Another important part of the framework that we will discuss is
  an efficient cost-based plan selection algorithm for queries.  Such a co
 st-based query optimizer is independent of the underlying physical data mo
 del and storage system and of the available logical operator implementatio
 ns\, depending on a set of well-defined APIs. Finally\, to round out the p
 resentation\, we will also present an implementation of those APIs\, inclu
 ding primitive access methods\, the physical operators\, statistics estima
 tors and cost models.
LOCATION:BC 420 https://plan.epfl.ch/?room==BC%20420
STATUS:CONFIRMED
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