Package se.liu.ida.hefquin.engine.queryproc.impl.loptimizer.heuristics
package se.liu.ida.hefquin.engine.queryproc.impl.loptimizer.heuristics
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ClassesClassDescriptionBase class for heuristics that use cardinality estimates to decide on a join order for the subplans of a multiway join or a binary join.A help class that wraps a
LogicalPlantogether with some information about this plan that is relevant for the algorithm of the main class (CardinalityBasedJoinOrderingBaseand that may be relevant for implementations of the abstract functions.This class is an implementation ofCardinalityBasedJoinOrderingBasethat uses cardinality requests.Pushes filter conditions as much as possible towards the leaf nodes of a given logical plan.Implement a greedy algorithm to determine the join order of sub-plans.Merges subplans that consists of multiple requests to the same federation member if such a merge is possible.In cases in which there are unions with requests under joins (which may happen only if we do not useUnionPullUp, this heuristics turns the requests into xxAdd operators with the previous join arguments as subplans.Pulls up all (multiway) union operators in the given plan as high up as possible.