Class: NoSE::Plans::QueryPlan

Inherits:
AbstractPlan show all
Extended by:
Forwardable
Includes:
Comparable, Enumerable
Defined in:
lib/nose/plans/query_planner.rb

Overview

A single plan for a query

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Enumerable

#partitions, #prefixes, #product_by, #sum_by

Constructor Details

#initialize(query, cost_model) ⇒ QueryPlan

Returns a new instance of QueryPlan.



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# File 'lib/nose/plans/query_planner.rb', line 167

def initialize(query, cost_model)
  @steps = []
  @query = query
  @cost_model = cost_model
end

Instance Attribute Details

#cost_model ⇒ Object

Returns the value of attribute cost_model.



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# File 'lib/nose/plans/query_planner.rb', line 157

def cost_model
  @cost_model
end

#query ⇒ Object

Returns the value of attribute query.



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# File 'lib/nose/plans/query_planner.rb', line 157

def query
  @query
end

#steps ⇒ Object (readonly)

Returns the value of attribute steps.



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# File 'lib/nose/plans/query_planner.rb', line 156

def steps
  @steps
end

Instance Method Details

#<=>(other) ⇒ Boolean

Two plans are compared by their execution cost

Returns:

  • (Boolean) 


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

def <=>(other)
  cost <=> other.cost
end

#cost ⇒ Numeric

The estimated cost of executing the query using this plan

Returns:

  • (Numeric) 


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

def cost
  costs = @steps.map(&:cost)
  costs.inject(0, &:+) unless costs.any?(&:nil?)
end

#group ⇒ String

Groups for plans are stored in the query

Returns:

  • (String) 


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# File 'lib/nose/plans/query_planner.rb', line 183

def group
  @query.group
end

#indexes ⇒ Array<Index>

Get the indexes used by this query plan

Returns:



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# File 'lib/nose/plans/query_planner.rb', line 219

def indexes
  @steps.select { |step| step.is_a? IndexLookupPlanStep }.map(&:index)
end

#name ⇒ String

Name plans after the associated query

Returns:

  • (String) 


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# File 'lib/nose/plans/query_planner.rb', line 189

def name
  @query.text
end

#params ⇒ Object

Parameters to this execution plan



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

def params
  @query.conditions
end

#select_fields ⇒ Array<Fields::Field>

Fields selected by this plan

Returns:



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# File 'lib/nose/plans/query_planner.rb', line 195

def select_fields
  @query.select
end

#weight ⇒ Fixnum

The weight of this query for a given workload

Returns:

  • (Fixnum) 


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# File 'lib/nose/plans/query_planner.rb', line 175

def weight
  return 1 if @workload.nil?

  @workload.statement_weights[@query]
end