module ScoutApm::Instruments::ActiveRecordInstruments
Contains ActiveRecord
instrument, aliasing +ActiveRecord::ConnectionAdapters::AbstractAdapter#log+ calls to trace calls to the database.
log
instrument.
log
is very close to where AR calls out to the database itself. We have access to the real SQL, and an AR generated “name” for the Query
Public Class Methods
prepended(instrumented_class)
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# File lib/scout_apm/instruments/active_record.rb, line 169 def self.prepended(instrumented_class) ScoutApm::Agent.instance.context.logger.info "Instrumenting #{instrumented_class.inspect}" end
Public Instance Methods
log(*args, &block)
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Calls superclass method
# File lib/scout_apm/instruments/active_record.rb, line 173 def log(*args, &block) # Extract data from the arguments sql, name = args metric_name = Utils::ActiveRecordMetricName.new(sql, name) desc = SqlList.new(sql) # Get current ScoutApm context req = ScoutApm::RequestManager.lookup current_layer = req.current_layer # If we call #log, we have a real query to run, and we've already # gotten through the cache gatekeeper. Since we want to only trace real # queries, and not repeated identical queries that just hit cache, we # mark layer as ignorable initially in #find_by_sql, then only when we # know it's a real database call do we mark it back as usable. # # This flag is later used in SlowRequestConverter to skip adding ignorable layers current_layer.annotate_layer(:ignorable => false) if current_layer # Either: update the current layer and yield, don't start a new one. if current_layer && current_layer.type == "ActiveRecord" # TODO: Get rid of call .to_s, need to find this without forcing a previous run of the name logic if current_layer.name.to_s == Utils::ActiveRecordMetricName::DEFAULT_METRIC current_layer.name = metric_name end if current_layer.desc.nil? current_layer.desc = SqlList.new end current_layer.desc.merge(desc) super(*args, &block) # OR: Start a new layer, we didn't pick up instrumentation earlier in the stack. else layer = ScoutApm::Layer.new("ActiveRecord", metric_name) layer.desc = desc req.start_layer(layer) begin super(*args, &block) ensure req.stop_layer end end end