discourse/lib/freedom_patches/fast_pluck.rb
Loïc Guitaut 357011eb3b DEV: Clean up freedom patches
This patch removes some of our freedom patches that have been deprecated
for some time now.
Some of them have been updated so we’re not shipping code based on an
old version of Rails.
2022-04-06 10:07:14 +02:00

89 lines
2.6 KiB
Ruby

# frozen_string_literal: true
# Speeds up #pluck so its about 2.2x faster, importantly makes pluck avoid creation of a slew
# of AR objects
#
#
class ActiveRecord::Relation
# Note: In discourse, the following code is included in lib/sql_builder.rb
#
# class RailsDateTimeDecoder < PG::SimpleDecoder
# def decode(string, tuple=nil, field=nil)
# if Rails.version >= "4.2.0"
# @caster ||= ActiveRecord::Type::DateTime.new
# @caster.type_cast_from_database(string)
# else
# ActiveRecord::ConnectionAdapters::Column.string_to_time string
# end
# end
# end
#
# class ActiveRecordTypeMap < PG::BasicTypeMapForResults
# def initialize(connection)
# super(connection)
# rm_coder 0, 1114
# add_coder RailsDateTimeDecoder.new(name: "timestamp", oid: 1114, format: 0)
# # we don't need deprecations
# self.default_type_map = PG::TypeMapInRuby.new
# end
# end
#
# def self.pg_type_map
# conn = ActiveRecord::Base.connection.raw_connection
# @typemap ||= ActiveRecordTypeMap.new(conn)
# end
class ::ActiveRecord::ConnectionAdapters::PostgreSQLAdapter
def select_raw(arel, name = nil, binds = [], &block)
arel = arel_from_relation(arel)
sql, binds = to_sql_and_binds(arel, binds)
execute_and_clear(sql, name, binds, &block)
end
end
def pluck(*column_names)
if loaded? && (column_names.map(&:to_s) - @klass.attribute_names - @klass.attribute_aliases.keys).empty?
return records.pluck(*column_names)
end
if has_include?(column_names.first)
relation = apply_join_dependency
relation.pluck(*column_names)
else
relation = spawn
relation.select_values = column_names
klass.connection.select_raw(relation.arel) do |result, _|
result.type_map = DB.type_map
result.nfields == 1 ? result.column_values(0) : result.values
end
end
end
end
# require 'benchmark/ips'
#
# ENV['RAILS_ENV'] = 'production'
# require File.expand_path("../../config/environment", __FILE__)
#
# Benchmark.ips do |x|
# x.report("fast_pluck") do
# Post.where(topic_id: 48464).fast_pluck(:id)
# end
#
# x.report("pluck") do
# Post.where(topic_id: 48464).pluck(:id)
# end
# end
#
# % ruby tmp/fast_pluck.rb
# Calculating -------------------------------------
# fast_pluck 165.000 i/100ms
# pluck 80.000 i/100ms
# -------------------------------------------------
# fast_pluck 1.720k (± 8.8%) i/s - 8.580k
# pluck 807.913 (± 4.0%) i/s - 4.080k
#