Class: ActiveWarehouse::Aggregate::DwarfAggregate

Inherits:
Aggregate
  • Object
show all
Includes:
DwarfCommon
Defined in:
lib/active_warehouse/aggregate/dwarf_aggregate.rb

Overview

Implementation of the Dwarf algorithm described in

Defined Under Namespace

Classes: Cell, Node

Instance Attribute Summary collapse

Attributes inherited from Aggregate

#cube_class

Instance Method Summary collapse

Methods included from DwarfCommon

#create_tuple, #dimension_order, #dimension_order=, #sorted_facts

Constructor Details

#initialize(cube_class) ⇒ DwarfAggregate

Initialize the aggregate



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# File 'lib/active_warehouse/aggregate/dwarf_aggregate.rb', line 8

def initialize(cube_class)
  super
end

Instance Attribute Details

#number_of_dimensions ⇒ Object

Accessor for the number of dimensions in the cube.



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# File 'lib/active_warehouse/aggregate/dwarf_aggregate.rb', line 179

def number_of_dimensions
  @number_of_dimensions
end

Instance Method Details

#calculate_aggregate(cells) ⇒ Object

Aggregate the node by summing all of the values in the cells TODO: support aggregations other than sum



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# File 'lib/active_warehouse/aggregate/dwarf_aggregate.rb', line 76

def calculate_aggregate(cells)
  value = Array.new(cells.first.value.length, 0)
  cells.each do |c|
    c.value.each_with_index do |v, index|
      value[index] += v
    end
  end
  value
end

#calculate_prefix(current_tuple, last_tuple) ⇒ Object

Calculates a common prefix between the two tuples



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# File 'lib/active_warehouse/aggregate/dwarf_aggregate.rb', line 185

def calculate_prefix(current_tuple, last_tuple)
  return [] if last_tuple.nil?
  prefix = []
  last_matched_index = nil
  0.upto(number_of_dimensions) do |i|
    if current_tuple[i] == last_tuple[i]
      prefix << current_tuple[i]
    else
      break
    end
  end
  prefix
end

#close_nodes(prefix) ⇒ Object

Close all of the last nodes that match the specified prefix and return the list of newly closed nodes



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# File 'lib/active_warehouse/aggregate/dwarf_aggregate.rb', line 201

def close_nodes(prefix)
  new_closed = []
  if @last_nodes
    @last_nodes[prefix.length + 1, @last_nodes.length].each do |n|
      n.closed = true
      new_closed << n
    end
  end
  new_closed
end

#create_dwarf_cube(sorted_facts) ⇒ Object

Create the dwarf cube with the sorted_facts



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# File 'lib/active_warehouse/aggregate/dwarf_aggregate.rb', line 87

def create_dwarf_cube(sorted_facts)
  last_tuple = nil
  @last_nodes = nil
  sorted_facts.each do |row|
    tuple = row.is_a?(Hash) ? create_tuple(row) : row
    
    prefix = calculate_prefix(tuple, last_tuple)
    
    close_nodes(prefix).each do |n|
      if n.leaf?
        n.all_cell = Cell.new('*', calculate_aggregate(n.cells))
      else
        n.all_cell = Cell.new('*')
        n.all_cell.child = suffix_coalesce(n.children)
      end
      n.processed = true
    end
    
    nodes = create_nodes(tuple, prefix)
    
    write_nodes(nodes)
    last_tuple = tuple
    if @last_nodes.nil? then @root_node = nodes.first end
    @last_nodes = nodes
  end
  
  # Alg 1, Line 13
  last_leaf_node = @last_nodes.last
  last_leaf_node.all_cell = Cell.new('*', calculate_aggregate(last_leaf_node.cells))
  
  # Alg 1, Line 14
  @last_nodes[0..@last_nodes.length - 2].reverse.each do |n|
    n.all_cell = Cell.new('*')
    n.all_cell.child = suffix_coalesce(n.children)
  end
  
  require File.dirname(__FILE__) + '/dwarf_printer'
  puts DwarfPrinter.print_node(@root_node)
end

#create_nodes(current_tuple, prefix) ⇒ Object

Create the nodes for the current tuple



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# File 'lib/active_warehouse/aggregate/dwarf_aggregate.rb', line 213

def create_nodes(current_tuple, prefix)
  nodes = []
  new_nodes_needed_for = []
  if @last_nodes.nil?
    0.upto(number_of_dimensions - 1) do |i|
      k = current_tuple[i]
      parent_cell = (nodes.last.nil?) ? nil : nodes.last.cells.last
      nodes << Node.new(k, parent_cell)
    end
  else
    if prefix.length > 0
      0.upto(prefix.length - 1) do |i|
        nodes << @last_nodes[i]
      end
    end
    k = current_tuple[prefix.length]
    n = @last_nodes[prefix.length]
    n.add_cell(Cell.new(k))
    nodes << n
    
    (prefix.length + 1).upto(number_of_dimensions - 1) do |i|
      k = current_tuple[i]
      parent_cell = (nodes.last.nil?) ? nil : nodes.last.cells.last
      nodes << Node.new(k, parent_cell)
    end
  end
  
  nodes.last.leaf = true
  cell = nodes.last.cells.last
  unless cell.value
    cell.value = current_tuple[number_of_dimensions..current_tuple.length-1]
  end
  
  nodes
end

#filter_nodes(node, dimension_ids, depth, filtered_nodes) ⇒ Object 



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# File 'lib/active_warehouse/aggregate/dwarf_aggregate.rb', line 59

def filter_nodes(node, dimension_ids, depth, filtered_nodes)
  #puts "filtering node #{print_node(node, depth, false)}"
  dimension = dimension_order[depth]
  #puts "dimension at #{depth} is #{dimension}"
  node.cells.each do |c|
    if dimension_ids[dimension].include?(c.key)
      if depth == dimension_order.length - 1
        filtered_nodes << node
      else
        filter_nodes(c.child, dimension_ids, depth+1, filtered_nodes) unless c.child.nil?
      end
    end
  end
end

#populate ⇒ Object

Populate the aggregate



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# File 'lib/active_warehouse/aggregate/dwarf_aggregate.rb', line 13

def populate
  create_dwarf_cube(sorted_facts)
end

#query(*args) ⇒ Object

query



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# File 'lib/active_warehouse/aggregate/dwarf_aggregate.rb', line 18

def query(*args)
  options = parse_query_args(*args)
  
  column_dimension_name = options[:column_dimension_name]
  column_hierarchy_name = options[:column_hierarchy_name]
  row_dimension_name = options[:row_dimension_name]
  row_hierarchy_name = options[:row_hierarchy_name]
  conditions = options[:conditions]
  cstage = options[:cstage]
  rstage = options[:rstage]
  filters = options[:filters]
  
  column_dimension = Dimension.class_for_name(column_dimension_name)
  row_dimension = Dimension.class_for_name(row_dimension_name)
  column_hierarchy = column_dimension.hierarchy(column_hierarchy_name)
  row_hierarchy = row_dimension.hierarchy(row_hierarchy_name)
  dimension_ids = {}
  
  dimension_order.each do |d|
    where_clause = []
    sql = "SELECT id FROM #{d.table_name}"
    filters.each do |key, value|
      dimension, column = key.split('.')
      if d.table_name == dimension
        where_clause << "#{dimension}.#{column} = '#{value}'" # TODO: protect from SQL injection
      end
    end
    sql += %Q(\nWHERE\n  #{where_clause.join(" AND\n  ")}) if where_clause.length > 0
    dimension_ids[d] = cube_class.connection.select_values(sql)
  end
  #puts "dimension ids: #{dimension_ids.inspect}"
  
  values = Array.new(cube_class.fact_class.aggregate_fields.length, 0)
  
  home_nodes = []
  filter_nodes(@root_node, dimension_ids, 0, home_nodes)
  #puts "filtered nodes: #{home_nodes.collect(&:id)}"
  
  values
end

#sorted_keys(nodes) ⇒ Object

Get a list of sorted keys for the cells in the specified nodes



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# File 'lib/active_warehouse/aggregate/dwarf_aggregate.rb', line 168

def sorted_keys(nodes)
  keys = []
  nodes.each do |n|
    n.cells.each do |c|
      keys << c.key
    end
  end
  keys.uniq.sort { |a, b| a <=> b }
end

#suffix_coalesce(nodes) ⇒ Object

Coalesce the nodes and return a single node



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# File 'lib/active_warehouse/aggregate/dwarf_aggregate.rb', line 128

def suffix_coalesce(nodes)
  if nodes.length == 1
    return nodes[0]
  else
    sub_dwarf = Node.new
    sub_dwarf.leaf = nodes.first.leaf
    
    keys = sorted_keys(nodes)
    keys.each do |k|
      to_merge = []
      nodes.each do |n|
        n.cells.each do |c|
          to_merge << c if c.key == k
        end
      end
      
      if sub_dwarf.leaf?
        cur_aggr = calculate_aggregate(to_merge)    # Alg 2, Line 8
        sub_dwarf.add_cell(Cell.new(k, cur_aggr))   # Alg 2, Line 9
      else
        # Alg 2, Line 11
        cell = Cell.new(k)
        cell.child = suffix_coalesce(to_merge.collect{|c| c.child})
        sub_dwarf.add_cell(cell)
      end
    end
    
    if sub_dwarf.leaf?
      sub_dwarf.all_cell = Cell.new("*", calculate_aggregate(sub_dwarf.cells))
    else
      cell = Cell.new("*")
      cell.child = suffix_coalesce(sub_dwarf.children)
      sub_dwarf.all_cell = cell
    end
  end
  
  sub_dwarf
end

#write_nodes(nodes) ⇒ Object

Write nodes to the filesystem.



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# File 'lib/active_warehouse/aggregate/dwarf_aggregate.rb', line 250

def write_nodes(nodes)
  # open(File.new(cube_class.name + '.dat'), 'w') do |f|
#           
#         end
end