Package org.jboss.dna.graph.query.optimize

This package contains the Optimizer interface, a rule-based optimizer implementation, and library of optimization rules.

See:
Description

Interface Summary

Optimizer	Interface for an optimizer.
OptimizerRule	Interface that defines an Optimizer rule.

Class Summary

AddAccessNodes	An optimizer rule that inserts an ACCESS above each SOURCE leaf node in a query plan.
ChooseJoinAlgorithm	An optimizer rule that choose the appropriate join algorithm and sets up any prerequisites, based upon the JoinCondition.
CopyCriteria	An optimizer rule that copies SELECT nodes that apply to one side of a equi-join condition so that they also apply to the other side fo the equi-join condition.
PushProjects	This rule attempts to ensure the proper location of PlanNode.Type.PROJECT nodes.
PushSelectCriteria	An optimizer rule that attempts to push the criteria nodes in a canonical plan down as far as possible.
RaiseSelectCriteria	An optimizer rule that moves up higher in the plan any SELECT node that appears below a JOIN node and that applies to selectors that are on the other side of the join.
RemoveEmptyAccessNodes	An optimizer rule that removes any ACCESS nodes that are known to never return any tuples because of conflicting constraints.
ReplaceAliases	An optimizer rule that changes any nodes that make use of an alias for a SOURCE, including columns, including criteria, project nodes, etc.
ReplaceViews	An optimizer rule that replaces any SOURCE nodes that happen to be views.
RewriteAsRangeCriteria	An optimizer rule that rewrites two AND-ed Constraints that constraint a dynamic operand to a range of values as a single Between constraint.
RewriteIdentityJoins	An optimizer rule that rewrites JOIN nodes that have equi-join criteria where the columns involved in the equi-join are all identity columns (that is, they form a key for the table).
RightOuterToLeftOuterJoins	An optimizer rule that converts right outer joins into left outer joins.
RuleBasedOptimizer	Optimizer implementation that optimizes a query using a stack of rules.

Package org.jboss.dna.graph.query.optimize Description

This package contains the Optimizer interface, a rule-based optimizer implementation, and library of optimization rules. The Optimizer is responsible for evaluating, validating, and manipulating a canonical query plan to produce a more a single optimized query processing plan. The query plan is often changed in situ, although this is not required of the Optimizer implementations. A library of existing OptimizerRule classes is provided, though it's very easy to add more optimizer rules.

The RuleBasedOptimizer is an implementation that optimizes a query using a stack of rules. A new stack is created for each rule, though the rules are required to be immutable and thus often shared and reused. And, the RuleBasedOptimizer is easily subclassed to define a custom stack of rules.