Class: OMF::Rete::Planner::JoinPlan

Inherits:
AbstractPlan show all
Defined in:
lib/omf_rete/planner/join_plan.rb

Overview

This class represents a planned join op.

Instance Attribute Summary

Attributes inherited from AbstractPlan

#cover_set, #result_set

Instance Method Summary collapse

Methods inherited from AbstractPlan

#complete, #complete?, #result_description, #used, #used?

Constructor Details

#initialize(stream1, stream2, joinSet, resultSet, coverSet, planBuilder) ⇒ JoinPlan

stream1 - first stream to join stream2 - second stream to join joinSet - set of bindings to join on resultSet - set of bindings in result coverSet - set of leaf nodes contributing to this result



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# File 'lib/omf_rete/planner/join_plan.rb', line 20

def initialize(stream1, stream2, joinSet, resultSet, coverSet, planBuilder)
  super coverSet, resultSet

  @planBuilder = planBuilder
  @left = stream1
  @right = stream2
  @join_set = joinSet
end

Instance Method Details

#cost ⇒ Object

Return the cost of this plan.

TODO: Some more meaningful heuristic will be nice



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# File 'lib/omf_rete/planner/join_plan.rb', line 67

def cost()
  unless @cost
    lcost = @left.cost()
    rcost = @right.cost()
    #@cost = 1 + 1.2 * (lcost > rcost ? lcost : rcost)
    @cost = 1 + 1.2 * (lcost + rcost)

  end
  @cost
end

#describe(out = STDOUT, offset = 0, incr = 2, sep = "\n") ⇒ Object 



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# File 'lib/omf_rete/planner/join_plan.rb', line 78

def describe(out = STDOUT, offset = 0, incr = 2, sep = "\n")
  out.write(" " * offset)
  result = @result_set.to_a.sort
  join = @join_set.to_a.sort
  out.write("join: [#{join.join(', ')}] => [#{result.join(', ')}] cost: #{cost}#{sep}")
  @left.describe(out, offset + incr, incr, sep)
  @right.describe(out, offset + incr, incr, sep)
end

#hash ⇒ Object

Create a hash for this plan which allows us to to identify identical plans.

Please note, that there is most likely a mroe efficient way to calculate a hash with the above properties



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# File 'lib/omf_rete/planner/join_plan.rb', line 53

def hash()
  unless @hash
    s = StringIO.new
    describe(s, 0, 0, '|')
    str = s.string
    @hash = str.hash
  end
  @hash
end

#materialize(indexPattern, resultSet, opts, &block) ⇒ Object

Materialize the plan. Create all the relevant operations and tuple sets to realize a configuration for the respective query. Returns the result set.



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# File 'lib/omf_rete/planner/join_plan.rb', line 33

def materialize(indexPattern, resultSet, opts, &block)
  unless resultSet
    description = @result_set.to_a.sort
    resultSet = IndexedTupleSet.new(description, indexPattern, nil, opts)
  end

  indexPattern = @join_set.to_a
  leftSet = @left.materialize(indexPattern, nil, opts)
  rightSet = @right.materialize(indexPattern, nil, opts)
  op = JoinOP.new(leftSet, rightSet, resultSet)
  resultSet.source = op
  resultSet
end

#to_s ⇒ Object 



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# File 'lib/omf_rete/planner/join_plan.rb', line 87

def to_s
  result = @result_set.to_a.sort
  join = @join_set.to_a.sort
  "JoinPlan [#{join.join(', ')}] out: [#{result.join(', ')}]"
end