Я хочу выполнить sql-запрос как параллелизм. поэтому я использую eventmachine и mysql2/em на ruby 2.1.1 на linux.eventmachine и mysql2/em не callback
Но eventmachine не вызывает обратный вызов.
Когда мой сценарий запуска, это outputed
"loop start"
"sql: select id from table where id = 1"
"loop end"
"loop start"
"sql: select id from table where id = 2"
"loop end"
"loop start"
"next loop"
"loop start"
"next loop"
.....
Я хочу, чтобы этот вывод.
"loop start"
"sql: select id from table where id = 1"
"loop end"
"loop start"
"sql: select id from table where id = 2"
"loop end"
"loop start"
"next loop"
"callback"
"results"
"loop start"
"sql: select id from table where id = 3"
.....
Что не так?
#!/usr/bin/env ruby
=begin
Gemfile
source 'https://rubygems.org'
gem 'eventmachine'
gem 'mysql2'
gem 'pry'
gem 'pry-debugger'
=end
require 'pp'
require 'bundler'
Bundler.require
require 'mysql2/em'
MYSQLINFO = {
host: 'localhost',
username: 'root',
password: '',
port: 3306,
}
SQLS = [
'select id from table where id = 1',
'select id from table where id = 2',
'select id from table where id = 3',
'select id from table where id = 4',
]
CONCURRENCY = 2
clients = []
CONCURRENCY.times do
clients << Mysql2::EM::Client.new(MYSQLINFO)
end
EM.run do
while true
pp 'loop start'
client = clients.shift
if client.nil?
# FIXME: I guess this point is wrong. Context must go to reactor thread?
# but I don't know how to do.
pp 'next loop'
next
end
sql = SQLS.shift
if sql.nil?
break
end
defer = client.query(sql)
pp "sql: #{sql}"
defer.callback do |results|
clients << client
pp 'callback'
pp results
end
pp 'loop end'
end
EM.stop
end