Class: NoSE::Plans::QueryExecutionPlan

Inherits:
AbstractPlan show all
Extended by:
Forwardable
Defined in:
lib/nose/plans/execution_plan.rb

Overview

DSL to construct query execution plans

Instance Attribute Summary collapse

Attributes inherited from AbstractPlan

#weight

Instance Method Summary collapse

Constructor Details

#initialize(group, name, schema, plans) ⇒ QueryExecutionPlan

Returns a new instance of QueryExecutionPlan.



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# File 'lib/nose/plans/execution_plan.rb', line 151

def initialize(group, name, schema, plans)
  @group = group
  @name = name
  @schema = schema
  @plans = plans
  @select_fields = []
  @params = {}
  @steps = []
  @update_steps = []
  @query_plans = []
end

Instance Attribute Details

#group ⇒ Object (readonly)

Returns the value of attribute group.



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# File 'lib/nose/plans/execution_plan.rb', line 142

def group
  @group
end

#index ⇒ Object (readonly)

Returns the value of attribute index.



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# File 'lib/nose/plans/execution_plan.rb', line 142

def index
  @index
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/nose/plans/execution_plan.rb', line 142

def name
  @name
end

#params ⇒ Object (readonly)

Returns the value of attribute params.



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# File 'lib/nose/plans/execution_plan.rb', line 142

def params
  @params
end

#query_plans ⇒ Object

Returns the value of attribute query_plans.



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# File 'lib/nose/plans/execution_plan.rb', line 144

def query_plans
  @query_plans
end

#select_fields ⇒ Object (readonly)

Returns the value of attribute select_fields.



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# File 'lib/nose/plans/execution_plan.rb', line 142

def select_fields
  @select_fields
end

#steps ⇒ Object (readonly)

Returns the value of attribute steps.



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# File 'lib/nose/plans/execution_plan.rb', line 142

def steps
  @steps
end

#update_steps ⇒ Object (readonly)

Returns the value of attribute update_steps.



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# File 'lib/nose/plans/execution_plan.rb', line 142

def update_steps
  @update_steps
end

Instance Method Details

#cost ⇒ Integer

The estimated cost of executing this plan

Returns:



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# File 'lib/nose/plans/execution_plan.rb', line 177

def cost
  costs = @steps.map(&:cost) + @update_steps.map(&:cost)
  costs += @query_plans.map(&:steps).flatten.map(&:cost)

  costs.inject(0, &:+)
end

#Delete(index_key) ⇒ void

This method returns an undefined value.

Add a new deletion step from an index



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# File 'lib/nose/plans/execution_plan.rb', line 265

def Delete(index_key)
  @index = @schema.indexes[index_key]

  step = Plans::DeletePlanStep.new @index

  # Get cardinality from last step of each support query plan
  # as in UpdatePlanner#find_plans_for_update
  cardinalities = @query_plans.map { |p| p.steps.last.state.cardinality }
  cardinality = cardinalities.inject(1, &:*)
  step.state = OpenStruct.new cardinality: cardinality

  @update_steps << step
end

#Insert(index_key, *fields) ⇒ void

This method returns an undefined value.

Add a new insertion step into an index



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# File 'lib/nose/plans/execution_plan.rb', line 248

def Insert(index_key, *fields)
  @index = @schema.indexes[index_key]

  # Get cardinality from last step of each support query plan
  # as in UpdatePlanner#find_plans_for_update
  cardinalities = @query_plans.map { |p| p.steps.last.state.cardinality }
  cardinality = cardinalities.inject(1, &:*)
  state = OpenStruct.new cardinality: cardinality

  fields = @index.all_fields if fields.empty?
  step = Plans::InsertPlanStep.new @index, state, fields

  @update_steps << step
end

#Lookup(index_key, *conditions, limit: nil) ⇒ void

This method returns an undefined value.

Create a new index lookup step with a particular set of conditions



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# File 'lib/nose/plans/execution_plan.rb', line 206

def Lookup(index_key, *conditions, limit: nil)
  index = @schema.indexes[index_key]

  step = Plans::IndexLookupPlanStep.new index
  eq_fields = Set.new
  range_field = nil
  conditions.each do |field, operator|
    if operator == :==
      eq_fields.add field
    else
      range_field = field
    end
  end

  step.instance_variable_set :@eq_filter, eq_fields
  step.instance_variable_set :@range_filter, range_field

  # XXX No ordering supported for now
  step.instance_variable_set :@order_by, []

  step.instance_variable_set :@limit, limit unless limit.nil?

  # Cardinality calculations adapted from
  # IndexLookupPlanStep#update_state
  state = OpenStruct.new
  if @steps.empty?
    state.hash_cardinality = 1
  else
    state.hash_cardinality = @steps.last.state.cardinality
  end
  cardinality = index.per_hash_count * state.hash_cardinality
  state.cardinality = Cardinality.filter cardinality,
                                         eq_fields - index.hash_fields,
                                         range_field

  step.state = state

  @steps << step
end

#Param(field, operator, value = nil) ⇒ void

This method returns an undefined value.

Add parameters which are used as input to the plan



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# File 'lib/nose/plans/execution_plan.rb', line 194

def Param(field, operator, value = nil)
  operator = :'=' if operator == :==
  @params[field.id] = Condition.new(field, operator, value)
end

#query ⇒ nil

These plans have no associated query

Returns:

  • (nil) 


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# File 'lib/nose/plans/execution_plan.rb', line 171

def query
  nil
end

#Select(*fields) ⇒ void

This method returns an undefined value.

Identify fields to be selected



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

def Select(*fields)
  @select_fields = fields.flatten.to_set
end

#Support(&block) ⇒ Object

Pass the support query up to the parent



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# File 'lib/nose/plans/execution_plan.rb', line 200

def Support(&block)
  @plans.Support(&block)
end

#update_fields ⇒ Array<Fields::Field>

Produce the fields updated by this plan

Returns:



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# File 'lib/nose/plans/execution_plan.rb', line 165

def update_fields
  @update_steps.last.fields
end