Class: NewRelic::Agent::TransactionSampler

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

Defined Under Namespace

Modules: Shim

Constant Summary collapse

BUILDER_KEY = 
:transaction_sample_builder
MAX_SQL_LENGTH =

some statements (particularly INSERTS with large BLOBS may be very large; we should trim them to a maximum usable length config is the driver configuration for the connection

16384

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ TransactionSampler

Returns a new instance of TransactionSampler.



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 19

def initialize
  @samples = []
  @harvest_count = 0
  @max_samples = 100
  @random_sample = nil
  config = NewRelic::Control.instance
  sampler_config = config.fetch('transaction_tracer', {})
  @segment_limit = sampler_config.fetch('limit_segments', 4000)
  @stack_trace_threshold = sampler_config.fetch('stack_trace_threshold', 0.500).to_f
  @samples_lock = Mutex.new
end

Instance Attribute Details

#disabled ⇒ Object (readonly)

Returns the value of attribute disabled.



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 17

def disabled
  @disabled
end

#last_sample ⇒ Object (readonly)

Returns the value of attribute last_sample.



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 17

def last_sample
  @last_sample
end

#random_sampling ⇒ Object

Returns the value of attribute random_sampling.



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 16

def random_sampling
  @random_sampling
end

#samples ⇒ Object (readonly)

Returns the value of attribute samples.



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 17

def samples
  @samples
end

#sampling_rate ⇒ Object

Returns the value of attribute sampling_rate.



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 16

def sampling_rate
  @sampling_rate
end

#stack_trace_threshold ⇒ Object

Returns the value of attribute stack_trace_threshold.



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 16

def stack_trace_threshold
  @stack_trace_threshold
end

Instance Method Details

#current_sample_id ⇒ Object 



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 31

def current_sample_id
  b=builder
  b and b.sample_id
end

#disable ⇒ Object 



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 36

def disable
  @disabled = true
  NewRelic::Agent.instance.stats_engine.remove_transaction_sampler self
end

#harvest(previous = nil, slow_threshold = 2.0) ⇒ Object

get the set of collected samples, merging into previous samples, and clear the collected sample list.



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 155

def harvest(previous = nil, slow_threshold = 2.0)
  return [] if disabled
  result = []
  previous ||= []
  
  previous = [previous] unless previous.is_a?(Array)
  
  previous_slowest = previous.inject(nil) {|a,ts| (a) ? ((a.duration > ts.duration) ? a : ts) : ts}
  
  @samples_lock.synchronize do
    
    if @random_sampling        
      @harvest_count += 1
      
      if (@harvest_count % @sampling_rate) == 0
        result << @random_sample if @random_sample
      else
        @random_sample = nil   # if we don't nil this out, then we won't send the slowest if slowest == @random_sample
      end
    end
    
    slowest = @slowest_sample
    @slowest_sample = nil
    
    if slowest && slowest != @random_sample && slowest.duration >= slow_threshold
      if previous_slowest.nil? || previous_slowest.duration < slowest.duration
        result << slowest
      else
        result << previous_slowest
      end
    end

    @random_sample = nil
    @last_sample = nil
  end
  # Truncate the samples at 2100 segments. The UI will clamp them at 2000 segments anyway.
  # This will save us memory and bandwidth.
  result.each { |sample| sample.truncate(@segment_limit) }
  result
end

#ignore_transaction ⇒ Object 



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 116

def ignore_transaction
  builder.ignore_transaction if builder
end

#notice_first_scope_push(time) ⇒ Object 



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 46

def notice_first_scope_push(time)
  start_builder(time) unless disabled
end

#notice_pop_scope(scope, time = Time.now.to_f) ⇒ Object 



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 80

def notice_pop_scope(scope, time = Time.now.to_f)
  return unless builder
  raise "frozen already???" if builder.sample.frozen?
  builder.trace_exit(scope, time)
end

#notice_profile(profile) ⇒ Object 



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 119

def notice_profile(profile)
  builder.set_profile(profile) if builder
end

#notice_push_scope(scope, time = Time.now.to_f) ⇒ Object 



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 50

def notice_push_scope(scope, time=Time.now.to_f)
  
  return unless builder
  
  builder.trace_entry(scope, time)
  
  # in developer mode, capture the stack trace with the segment.
  # this is cpu and memory expensive and therefore should not be
  # turned on in production mode
  if NewRelic::Control.instance.developer_mode?
    segment = builder.current_segment
    if segment
      # Strip stack frames off the top that match /new_relic/agent/
      trace = caller
      while trace.first =~/\/lib\/new_relic\/agent\//
        trace.shift
      end
      
      trace = trace[0..39] if trace.length > 40
      segment[:backtrace] = trace
    end
  end
end

#notice_scope_empty(time = Time.now.to_f) ⇒ Object

This is called when we are done with the transaction. We’ve unwound the stack to the top level.



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 88

def notice_scope_empty(time=Time.now.to_f)
  
  last_builder = builder
  return unless last_builder

  last_builder.finish_trace(time)
  clear_builder
  return if last_builder.ignored?

  @samples_lock.synchronize do
    @last_sample = last_builder.sample
    
    @random_sample = @last_sample if @random_sampling
    
    # ensure we don't collect more than a specified number of samples in memory
    @samples << @last_sample if NewRelic::Control.instance.developer_mode?
    @samples.shift while @samples.length > @max_samples
    
    if @slowest_sample.nil? || @slowest_sample.duration < @last_sample.duration
      @slowest_sample = @last_sample
    end
  end
end

#notice_sql(sql, config, duration) ⇒ Object 



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 132

def notice_sql(sql, config, duration)
  return unless builder
  if Thread::current[:record_sql] != false
    segment = builder.current_segment
    if segment
      current_sql = segment[:sql]
      sql = current_sql + ";\n" + sql if current_sql

      if sql.length > (MAX_SQL_LENGTH - 4)
        sql = sql[0..MAX_SQL_LENGTH-4] + '...'
      end
      
      segment[:sql] = sql
      segment[:connection_config] = config
      segment[:backtrace] = caller.join("\n") if duration >= @stack_trace_threshold 
    end
  end
end

#notice_transaction(path, uri = nil, params = {}) ⇒ Object 



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 112

def notice_transaction(path, uri=nil, params={})
  builder.set_transaction_info(path, uri, params) if !disabled && builder
end

#notice_transaction_cpu_time(cpu_time) ⇒ Object 



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 123

def notice_transaction_cpu_time(cpu_time)
  builder.set_transaction_cpu_time(cpu_time) if builder
end

#reset! ⇒ Object

reset samples without rebooting the web server



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 197

def reset!
  @samples = []
  @last_sample = nil
end

#scope_depth ⇒ Object 



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# File 'lib/new_relic/agent/transaction_sampler.rb', line 74

def scope_depth
  return 0 unless builder

  builder.scope_depth
end