Class: Shiba::IndexStats::Column

Inherits:
Object
  • Object
show all
Defined in:
lib/shiba/index_stats.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(column, index, rows_per, cardinality) ⇒ Column

Returns a new instance of Column.



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# File 'lib/shiba/index_stats.rb', line 73

def initialize(column, index, rows_per, cardinality)
  @column = column
  @index = index
  @rows_per = rows_per
  @cardinality = cardinality
end

Instance Attribute Details

#column ⇒ Object (readonly)

Returns the value of attribute column.



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# File 'lib/shiba/index_stats.rb', line 80

def column
  @column
end

#rows_per ⇒ Object 



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# File 'lib/shiba/index_stats.rb', line 90

def rows_per
  return @rows_per if @rows_per && @rows_per.is_a?(Integer)
  return nil if table_count.nil?

  if @rows_per.nil?
    if table_count == 0
      @rows_per = 1
    else
      @rows_per = (table_count / @cardinality).round
    end
  elsif @rows_per.is_a?(String)
    @rows_per = ((@rows_per.to_f / 100.0) * table_count.to_f).round
  end
  @rows_per
end

Instance Method Details

#encode_with(coder) ⇒ Object 



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# File 'lib/shiba/index_stats.rb', line 109

def encode_with(coder)
  coder.map = {'column' => @column}

  count = table_count
  count = 1 if count == 0
  ratio_per_item = self.rows_per / count.to_f

  if count <= 10
    ratio_threshold = 1_000_0000 # always show a number
  elsif count <= 1000
    ratio_threshold = 0.1
  elsif count <= 1_000_000
    ratio_threshold = 0.01
  else
    ratio_threshold = 0.001
  end

  if ratio_per_item > ratio_threshold
    coder.map['rows_per'] = (ratio_per_item * 100).round.to_s + "%"
  else
    coder.map['rows_per'] = rows_per
  end
  coder.tag = nil
end

#raw_cardinality ⇒ Object 



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# File 'lib/shiba/index_stats.rb', line 86

def raw_cardinality
  @cardinality
end

#table_count ⇒ Object 



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# File 'lib/shiba/index_stats.rb', line 82

def table_count
  @index.table.count
end