diff options
Diffstat (limited to 'activerecord/lib')
-rw-r--r-- | activerecord/lib/active_record/core.rb | 9 | ||||
-rw-r--r-- | activerecord/lib/active_record/railtie.rb | 8 | ||||
-rw-r--r-- | activerecord/lib/active_record/relation/record_fetch_warning.rb | 50 |
3 files changed, 67 insertions, 0 deletions
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb index 9a39a0e919..a17eb226f4 100644 --- a/activerecord/lib/active_record/core.rb +++ b/activerecord/lib/active_record/core.rb @@ -94,6 +94,15 @@ module ActiveRecord mattr_accessor :dump_schemas, instance_writer: false self.dump_schemas = :schema_search_path + ## + # :singleton-method: + # Specify a threshold for the size of query result sets. If the + # number of records in the set exceeds threshold, a warning is + # logged. This should be used to identify queries which pull + # thousands of records, which may cause memory bloat. + mattr_accessor :warn_on_records_fetched_greater_than, instance_writer: false + self.warn_on_records_fetched_greater_than = nil + mattr_accessor :maintain_test_schema, instance_accessor: false mattr_accessor :belongs_to_required_by_default, instance_accessor: false diff --git a/activerecord/lib/active_record/railtie.rb b/activerecord/lib/active_record/railtie.rb index f1bdbc845c..7e907beec0 100644 --- a/activerecord/lib/active_record/railtie.rb +++ b/activerecord/lib/active_record/railtie.rb @@ -102,6 +102,14 @@ module ActiveRecord end end + initializer "active_record.warn_on_records_fetched_greater_than" do + if config.active_record.warn_on_records_fetched_greater_than + ActiveSupport.on_load(:active_record) do + require 'active_record/relation/record_fetch_warning' + end + end + end + initializer "active_record.set_configs" do |app| ActiveSupport.on_load(:active_record) do app.config.active_record.each do |k,v| diff --git a/activerecord/lib/active_record/relation/record_fetch_warning.rb b/activerecord/lib/active_record/relation/record_fetch_warning.rb new file mode 100644 index 0000000000..0d31f73ddd --- /dev/null +++ b/activerecord/lib/active_record/relation/record_fetch_warning.rb @@ -0,0 +1,50 @@ +module ActiveRecord + class Relation + module RecordFetchWarning + # When this module is prepended to ActiveRecord::Relation and + # `config.active_record.warn_on_records_fetched_greater_than` is + # set to an integer, if the number of records a query returns is + # greater than the value of `warn_on_records_fetched_greater_than`, + # a warning is logged. This allows for the dection of queries that + # return a large number of records, which could cause memory + # bloat. + # + # In most cases, fetching large number of records can be performed + # efficiently using the ActiveRecord::Batches methods. + # See active_record/lib/relation/batches.rb for more information. + def exec_queries + QueryRegistry.reset + + super.tap do + if logger && warn_on_records_fetched_greater_than + if @records.length > warn_on_records_fetched_greater_than + logger.warn "Query fetched #{@records.size} #{@klass} records: #{QueryRegistry.queries.join(";")}" + end + end + end + end + + ActiveSupport::Notifications.subscribe("sql.active_record") do |*args| + payload = args.last + + QueryRegistry.queries << payload[:sql] + end + + class QueryRegistry # :nodoc: + extend ActiveSupport::PerThreadRegistry + + attr_accessor :queries + + def initialize + reset + end + + def reset + @queries = [] + end + end + end + end +end + +ActiveRecord::Relation.prepend ActiveRecord::Relation::RecordFetchWarning |