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require 'bundler/inline'
gemfile do
source 'https://rubygems.org'
gem 'pg'
gem 'activerecord', '5.2.0'
gem 'benchmark-ips'
end
require 'active_record'
require 'benchmark/ips'
ActiveRecord::Base.establish_connection(
:adapter => "postgresql",
:database => "test_db"
)
pg = ActiveRecord::Base.connection.raw_connection
pg.async_exec <<SQL
drop table if exists users
SQL
pg.async_exec <<SQL
create table users (
id int primary key,
name varchar(100)
)
SQL
class User < ActiveRecord::Base
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
class SqlBuilder
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
end
class ActiveRecord::Relation
def fast_pluck(*column_names)
if loaded? && (column_names.map(&:to_s) - @klass.attribute_names - @klass.attribute_aliases.keys).empty?
return records.fast_pluck(*column_names)
end
if has_include?(column_names.first)
relation = apply_join_dependency
relation.fast_pluck(*column_names)
else
enforce_raw_sql_whitelist(column_names)
relation = spawn
relation.select_values = column_names.map { |cn|
@klass.has_attribute?(cn) || @klass.attribute_alias?(cn) ? arel_attribute(cn) : cn
}
klass.connection.select_raw(relation) do |result, _|
result.type_map = SqlBuilder.pg_type_map
result.nfields == 1 ? result.column_values(0) : result.values
end
end
end
end
User.transaction do
10000.times do |id|
User.create!(id: id, name: "bob bob #{id}")
end
end
[1,10,100,1000,10_000].each do |n|
Benchmark.ips do |b|
b.report("fast pluck #{n} items") do |count|
while count > 0
User.limit(n).fast_pluck(:id)
count -= 1
end
end
b.report("pluck #{n} items") do |count|
while count > 0
User.limit(n).pluck(:id)
count -= 1
end
end
end
end
# sam@ubuntu fast_pluck % ruby test.rb
# Warming up --------------------------------------
# fast pluck 1 items 439.000 i/100ms
# pluck 1 items 454.000 i/100ms
# Calculating -------------------------------------
# fast pluck 1 items 4.518k (± 4.9%) i/s - 22.828k in 5.066392s
# pluck 1 items 4.520k (± 5.5%) i/s - 22.700k in 5.038813s
# Warming up --------------------------------------
# fast pluck 10 items 441.000 i/100ms
# pluck 10 items 439.000 i/100ms
# Calculating -------------------------------------
# fast pluck 10 items 4.212k (± 4.7%) i/s - 21.168k in 5.036280s
# pluck 10 items 4.329k (± 3.8%) i/s - 21.950k in 5.077540s
# Warming up --------------------------------------
# fast pluck 100 items 394.000 i/100ms
# pluck 100 items 338.000 i/100ms
# Calculating -------------------------------------
# fast pluck 100 items 4.026k (± 4.5%) i/s - 20.094k in 5.001355s
# pluck 100 items 3.614k (± 4.9%) i/s - 18.252k in 5.062923s
# Warming up --------------------------------------
# fast pluck 1000 items
# 225.000 i/100ms
# pluck 1000 items 129.000 i/100ms
# Calculating -------------------------------------
# fast pluck 1000 items
# 2.255k (± 3.5%) i/s - 11.475k in 5.093992s
# pluck 1000 items 1.308k (± 3.7%) i/s - 6.579k in 5.036949s
# Warming up --------------------------------------
# fast pluck 10000 items
# 50.000 i/100ms
# pluck 10000 items 18.000 i/100ms
# Calculating -------------------------------------
# fast pluck 10000 items
# 514.961 (± 3.9%) i/s - 2.600k in 5.056274s
# pluck 10000 items 184.925 (± 3.8%) i/s - 936.000 in 5.067828s
#
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@SamSaffron

SamSaffron May 30, 2018

Bypasses ActiveRecord for record this avoids grabbing string from PG and then converting to Integers. Used new(ish) PG type mapping.

Owner

SamSaffron commented May 30, 2018

Bypasses ActiveRecord for record this avoids grabbing string from PG and then converting to Integers. Used new(ish) PG type mapping.

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