TY - GEN
T1 - Semantic query optimization for processing XML streams with minimized memory footprint
AU - Li, Ming
AU - Mani, Murali
AU - Rundensteiner, Elke A.
PY - 2008
Y1 - 2008
N2 - XQuery evaluation over XML streams requires the temporary buffering of XML elements. This paper presents a semantic query optimization solution to minimize memory footprint during XQuery evaluation by exploiting schema knowledge. We focus on one particular class of constraints, namely, the Pattern Non-Occurrence (PNO) constraints for XML streams conforming to pre-defined DTDs. PNO constraints facilitate the early release of buffered data (early buffer release) or possibly avoid to ever store the data (buffer avoidance), thus achieving a minimized memory footprint. We develop an automaton-based technique to detect PNO constraints at runtime. For a given query, optimization opportunities of early buffer release and buffer avoidance which can be triggered by runtime PNO detection are explored and the optimization decision is then encoded into the Raindrop algebraic plan. We implement our optimization technique within the Raindrop XQuery engine. Our experimental studies illustrate that the proposed techniques bring significant performance improvement in both memory and CPU usage with little overhead.
AB - XQuery evaluation over XML streams requires the temporary buffering of XML elements. This paper presents a semantic query optimization solution to minimize memory footprint during XQuery evaluation by exploiting schema knowledge. We focus on one particular class of constraints, namely, the Pattern Non-Occurrence (PNO) constraints for XML streams conforming to pre-defined DTDs. PNO constraints facilitate the early release of buffered data (early buffer release) or possibly avoid to ever store the data (buffer avoidance), thus achieving a minimized memory footprint. We develop an automaton-based technique to detect PNO constraints at runtime. For a given query, optimization opportunities of early buffer release and buffer avoidance which can be triggered by runtime PNO detection are explored and the optimization decision is then encoded into the Raindrop algebraic plan. We implement our optimization technique within the Raindrop XQuery engine. Our experimental studies illustrate that the proposed techniques bring significant performance improvement in both memory and CPU usage with little overhead.
UR - http://www.scopus.com/inward/record.url?scp=67049100828&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=67049100828&partnerID=8YFLogxK
U2 - 10.1145/1416691.1416698
DO - 10.1145/1416691.1416698
M3 - Conference contribution
AN - SCOPUS:67049100828
SN - 9781595939661
T3 - 3rd International Workshop on Database Technologies for Handling XML Information on the Web, DataX'08 - Held at EDBT 2008: 11th International Conference on Extending Database Technology
SP - 27
EP - 36
BT - 3rd International Workshop on Database Technologies for Handling XML Information on the Web, DataX'08 - Held at EDBT 2008
T2 - 3rd International Workshop on Database Technologies for Handling XML Information on the Web DataX'08, Held in Conjunction with the International Conference on Extending Database Technology, EDBT'08
Y2 - 25 March 2008 through 25 March 2008
ER -