[Ruby]MySQL上のデータをCSV出力

dump.rb

#!/usr/bin/env ruby

require 'mysql2'
require 'csv'

table = "table_name" 
columns = "*" 
host = "localhost" 
username = "user" 
password = "password" 
database = "database" 

client = Mysql2::Client.new(
  host: host,
  username: username,
  password: password,
  database: database,
  stream: true,
  cache_rows: false,
)

results = client.query("select #{columns} from #{table}")

CSV.open("#{table}.csv", "w") do |csv|
  csv << results.fields
  results.each do |row|
    csv << row.values
  end
end

• stream: true, cache_rows: false あたりが無いとバッファリングしてメモリがあふれる
• ec2上でやったら時間がUTCになってた