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# frozen_string_literal: true
require 'test_helper'
require 'forwardable'
class FindOrCreateWorker
extend Forwardable
def_delegators :@thread, :join, :wakeup, :status, :to_s
def initialize(name, use_advisory_lock)
@name = name
@use_advisory_lock = use_advisory_lock
@thread = Thread.new { work_later }
end
def work_later
sleep
ApplicationRecord.connection_pool.with_connection do
if @use_advisory_lock
Tag.with_advisory_lock(@name) { work }
else
work
end
end
end
def work
Tag.transaction do
Tag.where(name: @name).first_or_create
end
end
end
class ParallelismTest < GemTestCase
def run_workers
@names = @iterations.times.map { |iter| "iteration ##{iter}" }
@names.each do |name|
workers = @workers.times.map do
FindOrCreateWorker.new(name, @use_advisory_lock)
end
# Wait for all the threads to get ready:
sleep(0.1) until workers.all? { |ea| ea.status == 'sleep' }
# OK, GO!
workers.each(&:wakeup)
# Then wait for them to finish:
workers.each(&:join)
end
# Ensure we're still connected:
ApplicationRecord.connection_pool.connection
end
setup do
ApplicationRecord.connection.reconnect!
@workers = 10
end
test 'creates multiple duplicate rows without advisory locks' do
skip if %i[sqlite3 jdbcsqlite3].include?(env_db)
@use_advisory_lock = false
@iterations = 1
run_workers
assert_operator(Tag.all.size, :>, @iterations) # <- any duplicated rows will make me happy.
assert_operator(TagAudit.all.size, :>, @iterations) # <- any duplicated rows will make me happy.
assert_operator(Label.all.size, :>, @iterations) # <- any duplicated rows will make me happy.
end
test "doesn't create multiple duplicate rows with advisory locks" do
@use_advisory_lock = true
@iterations = 10
run_workers
assert_equal(@iterations, Tag.all.size) # <- any duplicated rows will NOT make me happy.
assert_equal(@iterations, TagAudit.all.size) # <- any duplicated rows will NOT make me happy.
assert_equal(@iterations, Label.all.size) # <- any duplicated rows will NOT make me happy.
end
end
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