期刊名称：Bulletin of the Technical Committee on Data Engineering
出版年度：2008
卷号：31
期号：04
页码：15-15
出版社：IEEE Computer Society
摘要：In this paper, we describe the TIMBER XML database system implemented at University of Michigan.
TIMBER was one of the first native XML database systems, designed from the ground up to store and
query semi-structured data. A distinctive principle of TIMBER is its algebraic underpinning. Central
contributions of the TIMBER project include: (1) tree algebras that capture the structural nature of XML
queries; (2) the stack-based family of algorithms to evaluate structural joins; (3) new rule-based query
optimization techniques that take care of the heterogeneous nature of the intermediate results and take
the schema information into consideration; (4) cost-based query optimization techniques and summary
structures for result cardinality estimation; and (5) a family of structural indices for more efficient query
evaluation. In this paper, we describe not only the architecture of TIMBER, its storage model, and
engineering choices we made, but also present in hindsight, our retrospective on what went well and not
so well with our design and engineering choices.
