[Colloquium] Reminder: Jerome Simeon's talk today

[Margery Ishmael]

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DEPARTMENT OF COMPUTER SCIENCE - TALK

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Date: Friday, November 21, 2003
Time: 2:30 p.m.
Place: Ryerson 251

Speaker: JEROME SIMEON, Bells Labs

Title:  A Streaming Processor for XQuery

XQuery is a powerful language, which can be used not only to query XML
databases, but also in new XML applications: to set up a Web-service,
for information integration, as a component of the semantic-web
infrastructure, or for plain file processing.  These applications are
best served by a light-weight, easily embeddable XQuery implementation
without the overhead of a full-fledged database management
system. However, existing stand-alone XQuery implementations are not
appropriate due to their strong memory limitations.

I will present the architecture of an XQuery implementation that uses
streaming to support efficient in-memory query evaluation. The core of
this architecture is a hybrid nested-relational algebra extended with
streaming operators. I will present some algebraic rewritings
supported by the algebra, and illustrate the performance benefits of
those rewritings. More particularly, I will describe in detail a
"projection" operation, that can be applied to drastically reduce
memory requirements during query processing. The projection operation
operates by discarding portions of the input document that are not
necessary to evaluate a given query. It relies on a static analysis
algorithm that can compute the set of paths used within an XQuery
expression at compile time.

This work has been implemented within the Galax XQuery 1.0 processor,
which can be downloaded at:
http://db.bell-labs.com/galax/

The streaming architecture and algebra is joint work with Mary
Fernandez, from AT&T Labs. The projection algorithm is joint work with
Amelie Marian, from Columbia University and will be presented at the
upcoming VLDB'2003 conference, in Berlin, Germany.

Speaker's URL: http://www-db-out.bell-labs.com/user/simeon/

HOST: Svetlozar Nestorov

*Refreshments will follow the talk in Ryerson 255*

People in need of assistance should call 773-834-8977 in advance.