module ScoutApm::Instruments::ActiveRecordQueryingInstruments
Entry-point of instruments.
Instrumentation starts in ActiveRecord::Relation#exec_queries (Rails >= 3.2.0) or ActiveRecord::FinderMethods#find_with_assocations (previous Rails versions).
ActiveRecord::Querying#find_by_sql is instrumented in all Rails versions even though it is also invoked by exec_queries/#find_by_associations because it can be invoked directly from user code (e.g., Post.find_by_sql(“SELECT * FROM posts”)). The layer started by exec_queries/#find_by_assocations is marked to ignore children, so it will not cause duplicate layers in the former case.
These methods are early in the chain of calls invoked when executing an ActiveRecord
query, before the cache is consulted. If the query is later determined to be a cache miss, `#log` will be invoked, which we also instrument, and more details will be filled in (name, sql).
Caveats:
* We don't have a name for the query yet. * The query hasn't hit the cache yet. In the case of a cache hit, we won't hit #log, so won't get a name, leaving the misleading default. * One call here can result in several calls to #log, especially in the case where Rails needs to load the schema details for the table being queried.
Public Class Methods
# File lib/scout_apm/instruments/active_record.rb, line 303 def self.included(instrumented_class) ScoutApm::Agent.instance.context.logger.info "Instrumenting ActiveRecord::Querying - #{instrumented_class.inspect}" instrumented_class.class_eval do unless instrumented_class.method_defined?(:find_by_sql_without_scout_instruments) alias_method :find_by_sql_without_scout_instruments, :find_by_sql alias_method :find_by_sql, :find_by_sql_with_scout_instruments end end end
Public Instance Methods
# File lib/scout_apm/instruments/active_record.rb, line 313 def find_by_sql_with_scout_instruments(*args, **kwargs, &block) req = ScoutApm::RequestManager.lookup layer = ScoutApm::Layer.new("ActiveRecord", Utils::ActiveRecordMetricName::DEFAULT_METRIC) layer.annotate_layer(:ignorable => true) req.start_layer(layer) req.ignore_children! begin if ScoutApm::Agent.instance.context.environment.supports_kwarg_delegation? find_by_sql_without_scout_instruments(*args, **kwargs, &block) else find_by_sql_without_scout_instruments(*args, &block) end ensure req.acknowledge_children! req.stop_layer end end