ops

Documentation

Index

• type Operator
• type PhysicalOperator

Types

type Operator

type Operator interface {
	Clone(inputs []Operator) Operator
	Inputs() []Operator

	// AddPredicate is used to push predicates. It pushed it as far down as is possible in the tree.
	// If we encounter a join and the predicate depends on both sides of the join, the predicate will be split into two parts,
	// where data is fetched from the LHS of the join to be used in the evaluation on the RHS
	AddPredicate(ctx *plancontext.PlanningContext, expr sqlparser.Expr) (Operator, error)

	// AddColumn tells an operator to also output an additional column specified.
	// The offset to the column is returned.
	AddColumn(ctx *plancontext.PlanningContext, expr sqlparser.Expr) (int, error)
}

Operator forms the tree of operators, representing the declarative query provided. While planning, the operator tree starts with logical operators, and later moves to physical operators. The difference between the two is that when we get to a physical operator, we have made decisions on in which order to do the joins, and how to split them up across shards and keyspaces. In some situation we go straight to the physical operator - when there are no options to consider, we can go straight to the end result.

type PhysicalOperator

type PhysicalOperator interface {
	Operator
	IPhysical()
}

PhysicalOperator means that this operator is ready to be turned into a logical plan