Class: NewRelic::TransactionSample::Segment

Inherits:
Object
  • Object
show all
Defined in:
lib/new_relic/transaction_sample.rb

Direct Known Subclasses

CompositeSegment, FakeSegment, SummarySegment

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(timestamp, metric_name, segment_id) ⇒ Segment

Returns a new instance of Segment.



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# File 'lib/new_relic/transaction_sample.rb', line 35

def initialize(timestamp, metric_name, segment_id)
  @entry_timestamp = timestamp
  @metric_name = metric_name || '<unknown>'
  @segment_id = segment_id || object_id
end

Instance Attribute Details

#entry_timestamp ⇒ Object (readonly)

Returns the value of attribute entry_timestamp.



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# File 'lib/new_relic/transaction_sample.rb', line 27

def entry_timestamp
  @entry_timestamp
end

#exit_timestamp ⇒ Object (readonly)

The exit timestamp will be relative except for the outermost sample which will have a timestamp.



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# File 'lib/new_relic/transaction_sample.rb', line 30

def exit_timestamp
  @exit_timestamp
end

#metric_name ⇒ Object (readonly)

Returns the value of attribute metric_name.



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# File 'lib/new_relic/transaction_sample.rb', line 32

def metric_name
  @metric_name
end

#parent_segment ⇒ Object

Returns the value of attribute parent_segment.



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

def parent_segment
  @parent_segment
end

#segment_id ⇒ Object (readonly)

Returns the value of attribute segment_id.



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# File 'lib/new_relic/transaction_sample.rb', line 33

def segment_id
  @segment_id
end

Class Method Details

.from_json(json, id_generator) ⇒ Object 



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# File 'lib/new_relic/transaction_sample.rb', line 69

def self.from_json(json, id_generator)
  json = ActiveSupport::JSON.decode(json) if json.is_a?(String)
  if json.is_a?(Array)
    entry_timestamp = json[0].to_f / 1000
    exit_timestamp = json[1].to_f / 1000
    metric_name = json[2]
    params = json[3]
    called_segments = json[4]
  else
    entry_timestamp = json["entry_timestamp"].to_f
    exit_timestamp = json["exit_timestamp"].to_f
    metric_name =  json["metric_name"]       
    params = json["params"]
    
    called_segments = json["called_segments"]
  end
  segment = Segment.new(entry_timestamp, metric_name, id_generator.next_id)
  segment.end_trace exit_timestamp
  if params
    segment.send :params=, HashWithIndifferentAccess.new(params)
  end
  if called_segments
    called_segments.each do |child|
      segment.add_called_segment(self.from_json(child, id_generator))
    end
  end
  segment
end

Instance Method Details

#[](key) ⇒ Object 



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# File 'lib/new_relic/transaction_sample.rb', line 179

def [](key)
  params[key]
end

#[]=(key, value) ⇒ Object 



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

def []=(key, value)
  # only create a parameters field if a parameter is set; this will save
  # bandwidth etc as most segments have no parameters
  params[key] = value
end

#add_called_segment(s) ⇒ Object 



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# File 'lib/new_relic/transaction_sample.rb', line 45

def add_called_segment(s)
  @called_segments ||= []
  @called_segments << s
  s.parent_segment = self
end

#called_segments ⇒ Object 



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# File 'lib/new_relic/transaction_sample.rb', line 130

def called_segments
  @called_segments || EMPTY_ARRAY
end

#called_segments=(segments) ⇒ Object 



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# File 'lib/new_relic/transaction_sample.rb', line 263

def called_segments=(segments)
  @called_segments = segments
end

#count_segments ⇒ Object 



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# File 'lib/new_relic/transaction_sample.rb', line 151

def count_segments
  count = 1
  @called_segments.each { | seg | count  += seg.count_segments } if @called_segments
  count
end

#duration ⇒ Object

return the total duration of this segment



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# File 'lib/new_relic/transaction_sample.rb', line 135

def duration
  (@exit_timestamp - @entry_timestamp).to_f
end

#each_segment(&block) ⇒ Object

call the provided block for this segment and each of the called segments



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# File 'lib/new_relic/transaction_sample.rb', line 189

def each_segment(&block)
  block.call self
  
  if @called_segments
    @called_segments.each do |segment|
      segment.each_segment(&block)
    end
  end
end

#end_trace(timestamp) ⇒ Object 



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# File 'lib/new_relic/transaction_sample.rb', line 41

def end_trace(timestamp)
  @exit_timestamp = timestamp
end

#exclusive_duration ⇒ Object

return the duration of this segment without including the time in the called segments



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# File 'lib/new_relic/transaction_sample.rb', line 141

def exclusive_duration
  d = duration
  
  if @called_segments
    @called_segments.each do |segment|
      d -= segment.duration
    end
  end
  d
end

#explain_sql ⇒ Object

perform this in the runtime environment of a managed application, to explain the sql statement(s) executed within a segment of a transaction sample. returns an array of explanations (which is an array rows consisting of an array of strings for each column returned by the the explain query) Note this happens only for statements whose execution time exceeds a threshold (e.g. 500ms) and only within the slowest transaction in a report period, selected for shipment to RPM



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

def explain_sql        
  sql = params[:sql]
  return nil unless sql && params[:connection_config]
  statements = sql.split(";\n")
  explanations = []
  statements.each do |statement|
    if statement.split($;, 2)[0].upcase == 'SELECT'
      explain_resultset = []
      begin
        connection = NewRelic::TransactionSample.get_connection(params[:connection_config])    
        if connection
          # The resultset type varies for different drivers.  Only thing you can count on is
          # that it implements each.  Also: can't use select_rows because the native postgres
          # driver doesn't know that method.
          explain_resultset = connection.execute("EXPLAIN #{statement}") if connection
          rows = []
          # Note: we can't use map.
          # Note: have to convert from native column element types to string so we can
          # serialize.  Esp. for postgresql.
          # Can't use map.  Suck it up.
          if explain_resultset.respond_to?(:each)
            explain_resultset.each { | row | rows << row.map(&:to_s) }
          else
            rows << [ explain_resultset ]
          end
          explanations << rows
          # sleep for a very short period of time in order to yield to the main thread
          # this is because a remote database call will likely hang the VM
          sleep 0.05
        end
      rescue => e
        handle_exception_in_explain(e)
      end
    end
  end

  explanations
end

#find_segment(id) ⇒ Object 



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# File 'lib/new_relic/transaction_sample.rb', line 199

def find_segment(id)
  return self if @segment_id == id
  called_segments.each do |segment|
    found = segment.find_segment(id)
    return found if found
  end
  nil
end

#handle_exception_in_explain(e) ⇒ Object 



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# File 'lib/new_relic/transaction_sample.rb', line 253

def handle_exception_in_explain(e)
  x = 1 # this is here so that code coverage knows we've entered this block
  # swallow failed attempts to run an explain.  One example of a failure is the
  # connection for the sql statement is to a different db than the default connection
  # specified in AR::Base
end

#obfuscated_sql ⇒ Object

swallow failed attempts to run an explain. One example of a failure is the connection for the sql statement is to a different db than the default connection specified in AR::Base



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# File 'lib/new_relic/transaction_sample.rb', line 259

def obfuscated_sql
  TransactionSample.obfuscate_sql(params[:sql])
end

#params ⇒ Object 



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# File 'lib/new_relic/transaction_sample.rb', line 183

def params
  @params ||= {}
end

#path_string ⇒ Object 



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# File 'lib/new_relic/transaction_sample.rb', line 98

def path_string
  "#{metric_name}[#{called_segments.collect {|segment| segment.path_string }.join('')}]"
end

#to_debug_str(depth) ⇒ Object 



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# File 'lib/new_relic/transaction_sample.rb', line 109

def to_debug_str(depth)
  tab = "  " * depth 
  s = tab.clone
  s << ">> #{'%3i ms' % (@entry_timestamp*1000)} [#{self.class.name.split("::").last}] #{metric_name} \n"
  unless params.empty?
    params.each do |k,v|
      s << "#{tab}    -#{'%-16s' % k}: #{v.to_s[0..80]}\n"
    end
  end
  called_segments.each do |cs|
    s << cs.to_debug_str(depth + 1)
  end
  s << tab + "<< "
  s << case @exit_timestamp
    when nil then ' n/a'
    when Numeric then '%3i ms' % (@exit_timestamp*1000)
    else @exit_timestamp.to_s
  end
  s << " #{metric_name}\n"
end

#to_json ⇒ Object 



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# File 'lib/new_relic/transaction_sample.rb', line 55

def to_json
  map = {:entry_timestamp => @entry_timestamp,
    :exit_timestamp => @exit_timestamp,
    :metric_name => @metric_name,
    :segment_id => @segment_id}
  if @called_segments && !@called_segments.empty?
    map[:called_segments] = @called_segments
  end
  if @params && !@params.empty?
    map[:params] = @params
  end
  map.to_json
end

#to_s ⇒ Object 



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# File 'lib/new_relic/transaction_sample.rb', line 51

def to_s
  to_debug_str(0)
end

#to_s_compact ⇒ Object 



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# File 'lib/new_relic/transaction_sample.rb', line 101

def to_s_compact
  str = ""
  str << metric_name
  if called_segments.any?
    str << "{#{called_segments.map { | cs | cs.to_s_compact }.join(",")}}"
  end
  str
end

#truncate(max) ⇒ Object

Walk through the tree and truncate the segments



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# File 'lib/new_relic/transaction_sample.rb', line 157

def truncate(max)
  return max unless @called_segments
  i = 0
  @called_segments.each do | segment |
    max = segment.truncate(max)
    max -= 1
    if max <= 0
      @called_segments = @called_segments[0..i]
      break
    else
      i += 1
    end
  end
  max
end