Class: NoSE::Plans::UpdatePlanner

Inherits:
Object
  • Object
show all
Defined in:
lib/nose/plans/update_planner.rb

Overview

A planner for update statements in the workload

Instance Method Summary collapse

Constructor Details

#initialize(model, trees, cost_model, by_id_graph = false) ⇒ UpdatePlanner

Returns a new instance of UpdatePlanner.



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# File 'lib/nose/plans/update_planner.rb', line 188

def initialize(model, trees, cost_model, by_id_graph = false)
  @logger = Logging.logger['nose::update_planner']

  @model = model
  @cost_model = cost_model
  @by_id_graph = by_id_graph

  # Remove anything not a support query then group by statement and index
  @query_plans = trees.select do |tree|
    tree.query.is_a? SupportQuery
  end
  @query_plans = @query_plans.group_by { |tree| tree.query.statement }
  @query_plans.each do |plan_stmt, plan_trees|
    @query_plans[plan_stmt] = plan_trees.group_by do |tree|
      index = tree.query.index
      index = index.to_id_path if @by_id_path

      index
    end
  end
end

Instance Method Details

#find_plans_for_update(statement, indexes) ⇒ Array<UpdatePlan>

Find the necessary update plans for a given set of indexes

Returns:



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# File 'lib/nose/plans/update_planner.rb', line 212

def find_plans_for_update(statement, indexes)
  indexes = indexes.map(&:to_id_graph).to_set if @by_id_graph

  indexes.map do |index|
    next unless statement.modifies_index?(index)

    if (@query_plans[statement] &&
        @query_plans[statement][index]).nil?
      trees = []

      if statement.is_a? Insert
        cardinality = 1
      else
        cardinality = Cardinality.filter index.entries,
                                         statement.eq_fields,
                                         statement.range_field
      end
    else
      # Get the cardinality of the last step to use for the update state
      trees = @query_plans[statement][index]
      plans = trees.map do |tree|
        tree.select_using_indexes(indexes).min_by(&:cost)
      end

      # Multiply the cardinalities because we are crossing multiple
      # relationships and need the cross-product
      cardinality = plans.product_by { |p| p.last.state.cardinality }
    end

    state = UpdateState.new statement, cardinality
    update_steps = update_steps statement, index, state
    UpdatePlan.new statement, index, trees, update_steps, @cost_model
  end.compact
end