Module: NewRelic::Stats

Included in:
StatsBase
Defined in:
lib/new_relic/stats.rb

Instance Method Summary collapse

Instance Method Details

#absent? ⇒ Boolean

a stat is absent if its call count equals zero

Returns:

  • (Boolean) 


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# File 'lib/new_relic/stats.rb', line 6

def absent?
  call_count == 0
end

#apdex_score ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 249

def apdex_score
  s, t, f = get_apdex
  (s.to_f + (t.to_f / 2)) / (s+t+f).to_f
end

#as_percentage ⇒ Object

the stat total_call_time is a percent



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# File 'lib/new_relic/stats.rb', line 165

def as_percentage
  average_call_time * 100.0
end

#as_percentage_of(other_stats) ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 160

def as_percentage_of(other_stats)
  checked_calculation(total_call_time, other_stats.total_call_time) * 100.0
end

#average_call_time ⇒ Object Also known as: average_value, average_response_time 



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# File 'lib/new_relic/stats.rb', line 31

def average_call_time
  checked_calculation(total_call_time, call_count)
end

#average_exclusive_time ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 34

def average_exclusive_time
  checked_calculation(total_exclusive_time, call_count)
end

#calls_per_minute ⇒ Object Also known as: requests_per_minute 



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# File 'lib/new_relic/stats.rb', line 176

def calls_per_minute
  checked_calculation(call_count, duration) * 60
end

#checked_calculation(numerator, denominator) ⇒ Object

makes sure we aren’t dividing by zero



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# File 'lib/new_relic/stats.rb', line 23

def checked_calculation(numerator, denominator)
  if denominator.nil? || denominator == 0
    0.0
  else
    numerator.to_f / denominator
  end
end

#duration ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 169

def duration
  end_time ? (end_time - begin_time) : 0.0
end

#exclusive_time_percentage ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 201

def exclusive_time_percentage
  checked_calculation(total_exclusive_time, duration)
end

#expand_min_max_to(other) ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 82

def expand_min_max_to(other)
    self.min_call_time = other.min_call_time if min_time_less?(other)
    self.max_call_time = other.max_call_time if other.max_call_time > max_call_time
end

#fraction_of(s) ⇒ Object

calculate this set of stats to be a percentage fraction of the provided stats, which has an overlapping time window. used as a key part of the split algorithm



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# File 'lib/new_relic/stats.rb', line 222

def fraction_of(s)
  min_end = (end_time < s.end_time ? end_time : s.end_time)
  max_begin = (begin_time > s.begin_time ? begin_time : s.begin_time)
  percentage = (min_end - max_begin) / s.duration

  self.total_exclusive_time = s.total_exclusive_time * percentage
  self.total_call_time = s.total_call_time * percentage
  self.min_call_time = s.min_call_time
  self.max_call_time = s.max_call_time
  self.call_count = s.call_count * percentage
  self.sum_of_squares = (s.sum_of_squares || 0) * percentage
end

#get_apdex ⇒ Object

returns s,t,f



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# File 'lib/new_relic/stats.rb', line 245

def get_apdex
  [@call_count, @total_call_time.to_i, @total_exclusive_time.to_i]
end

#is_reset? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/new_relic/stats.rb', line 145

def is_reset?
  call_count == 0 && total_call_time == 0.0 && total_exclusive_time == 0.0
end

#merge(other_stats) ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 102

def merge(other_stats)
  stats = self.clone
  stats.merge!(other_stats)
end

#merge!(other_stats) ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 94

def merge!(other_stats)
  Array(other_stats).each do |other|
    merge_attributes(other)
  end

  self
end

#merge_attributes(other) ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 87

def merge_attributes(other)
  update_totals(other)
  expand_min_max_to(other)
  self.call_count += other.call_count
  update_boundaries(other)
end

#midpoint ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 173

def midpoint
  begin_time + (duration/2)
end

#min_time_less?(other) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/new_relic/stats.rb', line 78

def min_time_less?(other)
  (other.min_call_time < min_call_time && other.call_count > 0) || call_count == 0
end

#multiply_by(percentage) ⇒ Object

multiply the total time and rate by the given percentage



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# File 'lib/new_relic/stats.rb', line 236

def multiply_by(percentage)
  self.total_call_time = total_call_time * percentage
  self.call_count = call_count * percentage
  self.sum_of_squares = sum_of_squares * percentage

  self
end

#reset ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 149

def reset
  self.call_count = 0
  self.total_call_time = 0.0
  self.total_exclusive_time = 0.0
  self.min_call_time = 0.0
  self.max_call_time = 0.0
  self.sum_of_squares = 0.0
  self.begin_time = Time.at(0)
  self.end_time = Time.at(0)
end

#should_replace_begin_time?(other) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/new_relic/stats.rb', line 68

def should_replace_begin_time?(other)
  other.begin_time.to_f < begin_time.to_f || begin_time.to_f == 0.0
end

#should_replace_end_time?(other) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/new_relic/stats.rb', line 64

def should_replace_end_time?(other)
  end_time.to_f < other.end_time.to_f
end

#split(rollup_begin_time, rollup_period) ⇒ Object

split into an array of timeslices whose time boundaries start on (begin_time + (n * duration)) and whose end time ends on (begin_time * (n + 1) * duration), except for the first and last elements, whose begin time and end time are the begin and end times of this stats instance, respectively. Yield to caller for the code that creates the actual stats instance



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# File 'lib/new_relic/stats.rb', line 113

def split(rollup_begin_time, rollup_period)
  rollup_begin_time = rollup_begin_time.to_f
  rollup_begin_time += ((self.begin_time - rollup_begin_time) / rollup_period).floor * rollup_period

  current_begin_time = self.begin_time
  current_end_time = rollup_begin_time + rollup_period

  return [self] if current_end_time >= self.end_time

  timeslices = []
  while current_end_time < self.end_time do
    ts = yield(current_begin_time, current_end_time)
    if ts
      ts.fraction_of(self)
      timeslices << ts
    end
    current_begin_time = current_end_time
    current_end_time = current_begin_time + rollup_period
  end

  if self.end_time > current_begin_time
    percentage = rollup_period / self.duration + (self.begin_time - rollup_begin_time) / rollup_period
    ts = yield(current_begin_time, self.end_time)
    if ts
      ts.fraction_of(self)
      timeslices << ts
    end
  end

  timeslices
end

#stack_min_max_from(other) ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 54

def stack_min_max_from(other)
  self.min_call_time += other.min_call_time
  self.max_call_time += other.max_call_time
end

#standard_deviation ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 184

def standard_deviation
  return 0 if call_count < 2 || self.sum_of_squares.nil?

  # Convert sum of squares into standard deviation based on
  # formula for the standard deviation for the entire population
  x = self.sum_of_squares - (self.call_count * (self.average_value**2))
  return 0 if x <= 0

  Math.sqrt(x / self.call_count)
end

#sum_attributes(other) ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 47

def sum_attributes(other)
  update_totals(other)
  stack_min_max_from(other)
  self.call_count = [self.call_count, other.call_count].max
  update_boundaries(other)
end

#sum_merge!(other_stats) ⇒ Object

merge by adding to average response time

  • used to compose multiple metrics e.g. dispatcher time + mongrel queue time



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# File 'lib/new_relic/stats.rb', line 40

def sum_merge! (other_stats)
  Array(other_stats).each do |other|
    self.sum_attributes(other)
  end
  self
end

#summary ⇒ Object

Summary string to facilitate testing



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# File 'lib/new_relic/stats.rb', line 214

def summary
  format = "%m/%d/%y %I:%M%p"
  "[#{Time.at(begin_time.to_f).utc.strftime(format)} UTC, #{'%2.3fs' % duration.to_f}; #{'%2i' % call_count.to_i} calls #{'%4i' % average_call_time.to_f}s]"
end

#time_percentage ⇒ Object

returns the time spent in this component as a percentage of the total time window.



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# File 'lib/new_relic/stats.rb', line 197

def time_percentage
  checked_calculation(total_call_time, duration)
end

#time_str(value_ms) ⇒ Object

outputs a useful human-readable time given a value in milliseconds



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# File 'lib/new_relic/stats.rb', line 11

def time_str(value_ms)
  case
  when value_ms >= 10000
    "%.1f s" % (value_ms / 1000.0)
  when value_ms >= 5000
    "%.2f s" % (value_ms / 1000.0)
  else
    "%.0f ms" % value_ms
  end
end

#to_s ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 209

def to_s
  summary
end

#total_call_time_per_minute ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 180

def total_call_time_per_minute
  60.0 * time_percentage
end

#update_boundaries(other) ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 59

def update_boundaries(other)
  self.begin_time = other.begin_time if should_replace_begin_time?(other)
  self.end_time = other.end_time if should_replace_end_time?(other)
end

#update_totals(other) ⇒ Object 



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# File 'lib/new_relic/stats.rb', line 72

def update_totals(other)
  self.total_call_time      += other.total_call_time
  self.total_exclusive_time += other.total_exclusive_time
  self.sum_of_squares       += other.sum_of_squares
end