Projection Pushing Revisited

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Projection Pushing Revisited
The join operation, which combines tuples from multiple relations, is the most fundamental and, typically, the most expensive operation in database queries. The standard approach to join-query optimization is cost based, which requires developing a cost model, assigning an estimated cost to each queryprocessing plan, and searching in the space of all plans for a plan of minimal cost. Two other approaches can be found in the database-theory literature. The first approach, initially proposed by Chandra and Merlin, focused on minimizing the number of joins rather then on selecting an optimal join order. Unfortunately, this approach requires a homomorphism test, which itself is NP-complete, and has not been pursued in practical query processing. The second, more recent, approach focuses on structural properties of the query in order to find a project-join order that will minimize the size of intermediate results during query evaluation. For example, it is known that for Boolean project-joi...
Benjamin J. McMahan, Guoqiang Pan, Patrick Porter,
Added 08 Dec 2009
Updated 08 Dec 2009
Type Conference
Year 2004
Where EDBT
Authors Benjamin J. McMahan, Guoqiang Pan, Patrick Porter, Moshe Y. Vardi
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