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Speeding up Heterogeneous Data Access by Converting and Pushing Down String Comparisons
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W. Zhang and
P.-Å. Larson
View Paper (PDF)
Return to Poster Session 2: Interoperable Databases
Heterogeneous data access is becoming an important feature in database systems because it makes it possible to integrate information from a variety of data sources. The performance of queries involving external data sources is greatly affected by the cost of transporting data over the network. Pushing down subqueries, particularly selections and projections, to external data sources can reduce this cost. However, if the external data source uses a different collating sequence, the semantics of predicates involving string comparisons differ at the two site so such predicates cannot be pushed down unchanged. Our work is focused on how to convert predicates containing a comparison of a column with a string constant so that they can still be pushed down to the external data source.
Copyright(C) 2000 ACM
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