August 2009
Intermediate to advanced
893 pages
26h 48m
English
Content preview from Database Systems: Concepts, Design and Applications
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11.8. Structure of Query Evaluation Plans
An evaluation plan is used to define exactly what algorithm should be used for each operation and how the execution of the operations should be coordinated. So far we have discussed mainly two basic approaches to choosing an execution (action) plan namely, (a) heuristic optimization and (b) cost-based optimization. Most query optimisers combine the elements of both these approaches. Fig. 11.9 shows one of the possible evaluation plans.
Fig. 11.9. An evaluation plan
11.8.1. Query Execution Plan
The query execution plan may be classified into the following:
Left-deep (join) tree query execution plan. ...
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