memo

type ExploreMark int

type ExprIter struct {
	// Group and Element solely identify a Group expression.
	*Group
	*list.Element

	// Pattern describes the node of pattern tree.
	// The Operand type of the Group expression and the EngineType of the Group
	// must be matched with it.
	*pattern.Pattern

	// Children is used to iterate the child expressions.
	Children []*ExprIter
	// contains filtered or unexported fields
}

type Group struct {
	Equivalents *list.List

	FirstExpr    map[pattern.Operand]*list.Element
	Fingerprints map[string]*list.Element

	ImplMap map[string]Implementation
	Prop    *property.LogicalProperty

	EngineType pattern.EngineType

	SelfFingerprint string

	// ExploreMark is uses to mark whether this Group has been explored
	// by a transformation rule batch in a certain round.
	ExploreMark
	// contains filtered or unexported fields
}

type GroupExpr struct {
	ExprNode base.LogicalPlan
	Children []*Group
	Group    *Group

	// ExploreMark is uses to mark whether this GroupExpr has been fully
	// explored by a transformation rule batch in a certain round.
	ExploreMark
	// contains filtered or unexported fields
}

type Implementation interface {
	CalcCost(outCount float64, children ...Implementation) float64
	SetCost(cost float64)
	GetCost() float64
	GetPlan() plannercore.PhysicalPlan

	// AttachChildren is used to attach children implementations and returns it self.
	AttachChildren(children ...Implementation) Implementation

	// GetCostLimit gets the costLimit for implementing the next childGroup.
	GetCostLimit(costLimit float64, children ...Implementation) float64
}