Class: OpenTelemetry::SDK::Metrics::Aggregation::ExponentialHistogram::Buckets

Inherits:
Object
  • Object
show all
Defined in:
lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/buckets.rb

Overview

Buckets is the fundamental building block of exponential histogram that store bucket/boundary value

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Buckets

Returns a new instance of Buckets.



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# File 'lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/buckets.rb', line 16

def initialize
  @counts = [0]
  @index_base = 0
  @index_start = 0
  @index_end = 0
end

Instance Attribute Details

#index_base ⇒ Object

Returns the value of attribute index_base.



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# File 'lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/buckets.rb', line 14

def index_base
  @index_base
end

#index_end ⇒ Object

Returns the value of attribute index_end.



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# File 'lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/buckets.rb', line 14

def index_end
  @index_end
end

#index_start ⇒ Object

Returns the value of attribute index_start.



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# File 'lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/buckets.rb', line 14

def index_start
  @index_start
end

Instance Method Details

#copy_empty ⇒ Object

Returns a copy of these buckets with all counts reset to zero.



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# File 'lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/buckets.rb', line 115

def copy_empty
  new_buckets = self.class.new
  new_buckets.instance_variable_set(:@counts, Array.new(@counts.size, 0))
  new_buckets.instance_variable_set(:@index_base, @index_base)
  new_buckets.instance_variable_set(:@index_start, @index_start)
  new_buckets.instance_variable_set(:@index_end, @index_end)
  new_buckets
end

#downscale(amount) ⇒ Object

Halves the bucket resolution amount times, merging adjacent buckets.



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# File 'lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/buckets.rb', line 69

def downscale(amount)
  bias = @index_base - @index_start

  if bias != 0
    @index_base = @index_start
    @counts.reverse!
    @counts = @counts[0...bias].reverse + @counts[bias..].reverse
  end

  size = 1 + @index_end - @index_start
  each = 1 << amount
  inpos = 0
  outpos = 0
  pos = @index_start

  while pos <= @index_end
    mod = pos % each
    mod += each if mod < 0

    inds = mod

    while inds < each && inpos < size
      if outpos != inpos
        @counts[outpos] += @counts[inpos]
        @counts[inpos] = 0
      end

      inpos += 1
      pos   += 1
      inds  += 1
    end

    outpos += 1
  end

  @index_start >>= amount
  @index_end >>= amount
  @index_base = @index_start
end

#get_bucket(key) ⇒ Object

Returns the count stored at the given absolute bucket index.



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# File 'lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/buckets.rb', line 59

def get_bucket(key)
  bias = @index_base - @index_start

  key += @counts.size if key < bias
  key -= bias

  @counts[key]
end

#grow(needed, max_size) ⇒ Object

grow simply expand the @counts size



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# File 'lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/buckets.rb', line 24

def grow(needed, max_size)
  size = @counts.size
  bias = @index_base - @index_start
  old_positive_limit = size - bias

  new_size = [2**Math.log2(needed).ceil, max_size].min
  new_positive_limit = new_size - bias

  tmp = Array.new(new_size, 0)
  tmp[new_positive_limit..-1] = @counts[old_positive_limit..]
  tmp[0...old_positive_limit] = @counts[0...old_positive_limit]
  @counts = tmp
end

#increment_bucket(bucket_index, increment = 1) ⇒ Object

Increments the count at bucket_index by increment.



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# File 'lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/buckets.rb', line 110

def increment_bucket(bucket_index, increment = 1)
  @counts[bucket_index] += increment
end

#length ⇒ Object

Returns the number of populated buckets, from index_start to index_end.



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# File 'lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/buckets.rb', line 51

def length
  return 0 if @counts.empty?
  return 0 if @index_end == @index_start && counts[0] == 0

  @index_end - @index_start + 1
end

#offset ⇒ Object

Returns the lower index bound of the populated buckets.



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# File 'lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/buckets.rb', line 39

def offset
  @index_start
end

#offset_counts ⇒ Object Also known as: counts

Returns the bucket counts, rotated so index 0 aligns with #offset.



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# File 'lib/opentelemetry/sdk/metrics/aggregation/exponential_histogram/buckets.rb', line 44

def offset_counts
  bias = @index_base - @index_start
  @counts[-bias..] + @counts[0...-bias]
end