Our VLDB 2005 paper on the innards of our XQuery implementation is now available online. Shankar gave the presentation in Trondheim. As the previous conference papers, this paper gives an in-depth look into how we implement our XML and XQuery support. A must-read for anyone that wants to understand the "how we do it" and the why.
From the abstract:
This paper describes the experiences and the challenges in implementing XQuery in Microsoft’s SQL Server 2005. XQuery language constructs are compiled into an enhanced set of relational operators while preserving the semantics of XQuery. The query tree is optimized using relational optimization techniques, such as cost-based decisions, and rewrite rules based on XML schemas.