Title :
Speeding up heterogeneous data access by converting and pushing down string comparisons
Author :
Zhang, Weiye ; Larson, Per-Åke
Author_Institution :
Microsoft Corp., Redmond, WA, USA
Abstract :
Pushing down predicates to an external data source is critical to the performance for querying heterogeneous data sources. However, predicate-containing string comparisons cannot be pushed down unchanged if the external data source uses a different collating sequence. We describe a table-driven technique for rewriting such predicates to account for the differences in collation. In addition to precise conversion, we also consider imprecise conversion
Keywords :
query processing; rewriting systems; sequences; string matching; collating sequence; column comparison; conversion rule table; data transportation cost; database systems; domain constraints; external data sources; heterogeneous data access; imprecise conversion; long string truncation; precise conversion; predicate conversion; predicate discarding; predicate rewriting; predicate semantics; predicate simplification; predicate-containing string comparisons; prime implicants; query performance; range merging; string constant; subquery push-down; superfluous row filtering; table-driven technique; value range combination; Decision support systems; Fiber reinforced plastics; Virtual reality;
Conference_Titel :
Data Engineering, 1999. Proceedings., 15th International Conference on
Conference_Location :
Sydney, NSW
Print_ISBN :
0-7695-0071-4
DOI :
10.1109/ICDE.1999.754941
