cascades

Documentation

Index

• type Operand
  • func GetOperand(p plannercore.LogicalPlan) (Operand, error)
• type Pattern
  • func BuildPattern(operand Operand, children ...*Pattern) *Pattern

Types

type Operand

type Operand int

Operand is the node of a pattern tree, it represents a logical expression operator. Different from logical plan operator which holds the full information about an expression operator, Operand only stores the type information. An Operand may correspond to a concrete logical plan operator, or it can has special meaning, e.g, a placeholder for any logical plan operator.

const (
	// OperandAny is a placeholder for any Operand.
	OperandAny Operand = iota
	// OperandJoin for LogicalJoin.
	OperandJoin
	// OperandAggregation for LogicalAggregation.
	OperandAggregation
	// OperandProjection for LogicalProjection.
	OperandProjection
	// OperandSelection for LogicalSelection.
	OperandSelection
	// OperandApply for LogicalApply.
	OperandApply
	// OperandMaxOneRow for LogicalMaxOneRow.
	OperandMaxOneRow
	// OperandTableDual for LogicalTableDual.
	OperandTableDual
	// OperandDataSource for DataSource.
	OperandDataSource
	// OperandUnionScan for LogicalUnionScan.
	OperandUnionScan
	// OperandUnionAll for LogicalUnionAll.
	OperandUnionAll
	// OperandSort for LogicalSort.
	OperandSort
	// OperandTopN for LogicalTopN.
	OperandTopN
	// OperandLock for LogicalLock.
	OperandLock
	// OperandLimit for LogicalLimit.
	OperandLimit
	// OperandUnsupported is upper bound of defined Operand yet.
	OperandUnsupported
)

func GetOperand

func GetOperand(p plannercore.LogicalPlan) (Operand, error)

GetOperand maps logical plan operator to Operand.

type Pattern

type Pattern struct {
	// contains filtered or unexported fields
}

Pattern defines the match pattern for a rule. It describes a piece of logical expression. It's a tree-like structure and each node in the tree is an Operand.

func BuildPattern

func BuildPattern(operand Operand, children ...*Pattern) *Pattern

BuildPattern builds a Pattern from Operand and child Patterns. Used in GetPattern() of Transformation interface to generate a Pattern.