Class: Veritas::Optimizer::Algebra::Join::LeftMaterializedOperand

Inherits:

Veritas::Optimizer::Algebra::Join

• Object
• Veritas::Optimizer
• Relation::Operation::Binary
• Relation::Operation::Combination
• Veritas::Optimizer::Algebra::Join
• Veritas::Optimizer::Algebra::Join::LeftMaterializedOperand

Defined in:

lib/veritas/optimizer/algebra/join.rb

Overview

Optimize when the left operand is materialized

Constant Summary

Constants inherited from Veritas::Optimizer::Algebra::Join

CONTRADICTION

Constants inherited from Veritas::Optimizer

Noop, VERSION

Instance Attribute Summary

Attributes included from Function::Binary

#left, #right

Attributes inherited from Veritas::Optimizer

#operation

Instance Method Summary

• #optimizable? ⇒ Boolean private

  Test if the left operand is materialized.

• #optimize ⇒ Algebra::Join private

  Return the join of the left and right with the right restricted.

Methods included from Function::Binary

#initialize

Methods inherited from Veritas::Optimizer

chain, #initialize

Instance Method Details

#optimizable? ⇒ Boolean

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Test if the left operand is materialized

Returns:

• (Boolean)

# File 'lib/veritas/optimizer/algebra/join.rb', line 88

def optimizable?
  left.materialized? && ! right_matching_left?
end

#optimize ⇒ Algebra::Join

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Return the join of the left and right with the right restricted

Returns:

• (Algebra::Join)

# File 'lib/veritas/optimizer/algebra/join.rb', line 97

def optimize
  left.join(right.restrict { materialized_predicate })
end