class MrTuner

# File lib/mrtuner.rb, line 5
def initialize(type, memory, config = {})
  @type                      = type.downcase
  @memory                    = memory * 1073741824
  @connections               = config['connections']
  @oversubscribe             = config.key?("oversubscribe") ? config['oversubscribe'] : config['connections']
  @block_size                = config.key?("block_size") ? config['block_size'] : 8192
  @wal_block_size            = config.key?("wal_block_size") ? config['block_size'] : 8192
  @max_locks_per_transaction = config.key?("max_locks_per_transaction") ? config['max_locks_per_transaction'] : 64
  @autovacuum_max_workers    = config.key?("autovacuum_max_workers") ? config['autovacuum_max_workers'] : 3
  @max_prepared_transactions = config.key?("max_prepared_transactions") ? config['max_prepared_transactions'] : 0
  @page_size                 = config.key?("page_size") ? config['page_size'] : 4096
end

# File lib/mrtuner.rb, line 29
def display_config
  get_config.each do |k,v|
    case k
    when :maintenance_work_mem,:work_mem,:shared_buffers,:effective_cache_size
      puts "#{k} = #{as_size(v)}"
    else
      puts "#{k} = #{v}"
    end
  end
end

# File lib/mrtuner.rb, line 18
def get_config
  {
    :max_connections              => max_connections,
    :maintenance_work_mem         => make_round_number(maintenance_work_mem),
    :work_mem                     => make_round_number(work_mem.round),
    :checkpoint_completion_target => checkpoint_completion_target,
    :shared_buffers               => make_round_number(shared_buffers),
    :effective_cache_size         => make_round_number(effective_cache_size),
  }
end

# File lib/mrtuner.rb, line 98
def checkpoint_completion_target
  case @type
  when 'web'
    0.7
  when 'oltp', 'dw', 'mixed'
    0.9
  when 'desktop'
    0.5
  end
end

# File lib/mrtuner.rb, line 66
def effective_cache_size
  # return 134217728 if @memory <  268435456
  # return 2147483648 if @memory < 2147483648
  case @type
  when 'oltp','dw','web','mixed'
    @memory * 0.75
  else
    @memory / 4
  end
end

# File lib/mrtuner.rb, line 88
def maintenance_work_mem
  case @type
  when 'web', 'oltp', 'mixed', 'desktop'
    mwm = @memory / 16
  when 'dw'
    mwm = @memory / 8
  end
  mwm > 1073741824 ? 1073741824 : mwm
end

# File lib/mrtuner.rb, line 41
def max_connections
  return @oversubscribe if @oversubscribe
  case @type
  when 'oltp'
    @connections = 300
  when 'dw'
    @connections = 20
  when 'mixed'
    @connections = 80
  when 'desktop'
    @connections = 5
  else
    @connections = 200
  end
end

# File lib/mrtuner.rb, line 57
def shared_buffers
  case @type
  when 'oltp','dw','web','mixed'
    @memory / 4
  else
    @memory / 16
  end
end

# File lib/mrtuner.rb, line 77
def work_mem
  case @type
  when 'web', 'oltp'
    @memory / @connections
  when 'dw', 'mixed'
    @memory / @connections / 2
  when 'desktop'
    @memory / @connections / 6
  end
end