mymemcheck.rb

#!/usr/bin/env ruby

# 1. my.cnf か SHOW VARIABLES の結果を入力にとる
# 2. 入力を解析し、必要なパラメータ値を取得する
# 3. 計算
# 4. 結果を標準出力に出力する

require 'optparse'
require 'bigdecimal'

Version = '0.0.1'

class String
  def to_byte
    return unless /(\d+)([KMG]?)/ =~ self
    value, unit = $1.to_i, $2
    case unit
    when 'K'
      value * 1024
    when 'M'
      value * 1048576
    when 'G'
      value * 1073741824
    end
    value
  end
end

class Fixnum
  def to_s_with_byte_unit(base = 10)
    if base.to_sym == :byte
      raise "Too large value: #{self}" if self >= 1099511627776 # supported units are ['', 'K', 'M', 'G'].
      border = BigDecimal('1024')
      value = BigDecimal(self.to_s)
      unit = 0
      while value >= border
        value /= border
        unit += 1
      end
      "%3.2f%s" % [value, ['', 'K', 'M', 'G'][unit]]
    else
      to_s_without_byte_unit(base)
    end
  end
  alias_method :to_s_without_byte_unit, :to_s
  alias_method :to_s, :to_s_with_byte_unit
end

class MyMemCheck

  @@global_buffers = %w(key_buffer_size innodb_additional_mem_pool_size innodb_buffer_pool_size innodb_log_buffer_size)
  @@thread_buffers = %w(net_buffer_length read_buffer_size read_rnd_buffer_size sort_buffer_size myisam_sort_buffer_size join_buffer_size thread_stack)

  def initialize
    @cmd_options = parse_cmd_options
    @variables = {}
  end

  def run
    read_variables
    validate_variables
    report_minimal_memory
    report_innodb_log_file
  end

  private

  def parse_cmd_options
    options = {}
    OptionParser.new do |opt|
      opt.on('-f path', 'パラメータを path から読み込む(書式は my.cnf に従う)') do |v|
        raise "No such file: #{v}" unless File.exists?(v)
        options[:file] = v
      end
      opt.parse!(ARGV)
    end
    options
  end

  def read_variables
    @variables = {}
    @cmd_options[:file] ? read_variables_from_conf : read_variables_from_mysql
  end

  def read_variables_from_conf
    open(@cmd_options[:file]) do |input|
      in_mysqld = false
      input.each do |line|
        line.chomp!
        in_mysqld = (line == '[mysqld]') if line[0,1] == '['
        next if line.empty? or /\A#/ =~ line or line[0,1] == '['
        next unless in_mysqld
        next unless /\A(.+)=(.+)\z/ =~ line
        name, value = $1.strip, $2.strip
        if bytes = value.to_byte
          @variables[name] = bytes
        end
      end
    end
  end

  def read_variables_from_mysql
    while line = ARGF.gets
      line.chomp!
      name, value = line.split("\t")
      if value and bytes = value.to_byte
        @variables[name] = bytes
      end
    end
  end

  def validate_variables
    missing_variables = (@@global_buffers + @@thread_buffers) - @variables.keys
    unless missing_variables.empty?
      raise "[ABORT] missing variables:\n" + missing_variables.map{|name| "\t* #{name}" }.join("\n")
    end
  end

  def report_minimal_memory
    global_memory = @variables.values_at(*@@global_buffers).inject(0) {|r,v| r += v}
    thread_memory = @variables.values_at(*@@thread_buffers).inject(0) {|r,v| r += v}
    all_thread_memory = thread_memory * @variables['max_connections']
    total = global_memory + all_thread_memory

    puts <<EOS
GLOBAL BUFFERS:
#{@@global_buffers.map{|name| "\t%-40s = %7sB" % [name, @variables[name].to_s(:byte)] }.join("\n")}
#{"\t%-40s = %7sB" % ['', global_memory.to_s(:byte)]}

THREAD BUFFERS:
#{@@thread_buffers.map{|name| "\t%-40s = %7sB" % [name, @variables[name].to_s(:byte)] }.join("\n")}
#{"\t%-40s = %7sB * max_connections(=%d)" % ['', thread_memory.to_s(:byte), @variables['max_connections']]}
#{"\t%-40s = %7sB" % ['', all_thread_memory.to_s(:byte)]}

#{"\t%40s = %7sB" % ['TOTAL', total.to_s(:byte)]}

EOS
  end

  def report_innodb_log_file
    innodb_log_file_size = @variables['innodb_log_file_size']
    max_innodb_log_file_size = @variables['innodb_buffer_pool_size'] / @variables['innodb_log_files_in_group']
    safe_mark = (1048576..4294967296).include?(innodb_log_file_size) && (innodb_log_file_size <= max_innodb_log_file_size) ? 'safe' : 'out of safety range (too small or too large)'

    puts <<EOS
InnoDB log file:

\t1MB < innodb_log_file_size < MAX_innodb_log_file_size < 4GB
\tMAX_innodb_log_file_size = innodb_log_buffer_pool_size / innodb_log_files_in_group

#{"\t%-40s = %7sB" % ['innodb_log_buffer_size', @variables['innodb_log_buffer_size'].to_s(:byte)]}
#{"\t%-40s = %8d" % ['innodb_log_files_in_group', @variables['innodb_log_files_in_group']]}
#{"\t%-40s = %7sB" % ['innodb_log_file_size', @variables['innodb_log_file_size'].to_s(:byte)]}
#{"\t%-40s = %7sB .. %s" % ['MAX_innodb_log_file_size', max_innodb_log_file_size.to_s(:byte), safe_mark]}

EOS
  end
end

begin
  mymemcheck = MyMemCheck.new
  mymemcheck.run
rescue
  puts $!
end