Class: Tableflip::Executor

Inherits:
Object
  • Object
show all
Defined in:
lib/tableflip/executor.rb

Defined Under Namespace

Classes: BinaryString

Instance Method Summary collapse

Constructor Details

#initialize(strategy) ⇒ Executor

Instance Methods =====================================================



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# File 'lib/tableflip/executor.rb', line 7

def initialize(strategy)
  @strategy = strategy

  @time_format = '%Y-%m-%d %H:%M:%S'
end

Instance Method Details

#await ⇒ Object 



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# File 'lib/tableflip/executor.rb', line 17

def await
  @await ||= Hash.new { |h, k| h[k] = [ ] }

  fibers = @await[Fiber.current]

  fibers << Fiber.current

  yield if (block_given?)

  fibers.delete(Fiber.current)

  while (fibers.any?)
    Fiber.yield
  end
end

#defer ⇒ Object 



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# File 'lib/tableflip/executor.rb', line 33

def defer
  parent_fiber = Fiber.current

  fibers = @await[parent_fiber]

  fiber = Fiber.new do
    yield if (block_given?)

    fibers.delete(Fiber.current)

    parent_fiber.resume
  end

  fibers << fiber

  EventMachine.next_tick do
    fiber.resume
  end
end

#do_query(db, query, *values) ⇒ Object 



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# File 'lib/tableflip/executor.rb', line 161

def do_query(db, query, *values)
  fiber = Fiber.current
  query = query.gsub('?') do |s|
    escaper(db, values.shift)
  end

  if (@strategy.debug_queries?)
    puts "SQL> #{query}"
  end

  completed = false

  while (!completed)
    begin
      deferred = db.query(query)

      deferred.callback do |result|
        EventMachine.next_tick do
          completed = true

          fiber.resume(result)
        end
      end

      deferred.errback do |err|
        EventMachine.next_tick do
          completed = true

          fiber.resume(err)
        end
      end

      case (response = Fiber.yield)
      when Exception
        raise response
      else
        return response
      end

    rescue Mysql2::Error => e
      if (e.to_s.match(/MySQL server has gone away/))
        # Ignore
      else
        raise e
      end
    end
  end
end

#escaper(db, value) ⇒ Object 



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# File 'lib/tableflip/executor.rb', line 142

def escaper(db, value)
  case (value)
  when nil
    'NULL'
  when BinaryString
    "0x%s" % value.unpack("H*")
  when Fixnum
    value
  when Date
    '"' + db.escape(value.strftime('%Y-%m-%d')) + '"'
  when DateTime, Time
    '"' + db.escape(value.utc.strftime('%Y-%m-%d %H:%M:%S')) + '"'
  when Array
    value.collect { |v| escaper(db, v) }.join(',')
  else
    '"' + db.escape(value.to_s) + '"'
  end
end

#execute! ⇒ Object 



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# File 'lib/tableflip/executor.rb', line 53

def execute!
  require 'eventmachine'
  require 'em-synchrony'

  if (@strategy.message)
    puts @strategy.message
    exit(0)
  end

  tables = { }

  EventMachine.synchrony do
    if (@strategy.tables.include?(:__all__))
      source_db = Tableflip::DatabaseHandle.connect(
        @strategy.source_env,
        :encoding => @strategy.encoding
      )

      @strategy.tables.delete(:__all__)

      result = do_query(source_db, "SHOW TABLES")

      result.each do |row|
        table_name = row.first[1]

        case (table_name)
        when 'schema_migrations', /__changes/
          next
        end

        @strategy.tables << table_name
      end
    end

    await do
      @strategy.tables.each do |table|
        defer do
          queue = @strategy.actions.dup

          table_config = tables[table] = {
            :table => table,
            :queue => queue
          }
              
          while (action = queue.shift)
            log("#{table} [#{action}]")

            source_db = Tableflip::DatabaseHandle.connect(
              @strategy.source_env,
              :encoding => @strategy.encoding
            )

            case (action)
            when :tracking_add
              tracking_add(source_db, table_config)
            when :tracking_remove
              tracking_remove(source_db, table_config)
            when :tracking_seed
              tracking_seed(source_db, table_config)
            when :table_migrate
              @strategy.complete = false

              target_db = Tableflip::DatabaseHandle.connect(
                @strategy.target_env,
                :encoding => @strategy.encoding
              )
              table_migrate(source_db, target_db, table_config)
            when :table_report_status
              target_db = Tableflip::DatabaseHandle.connect(
                @strategy.target_env,
                :encoding => @strategy.encoding
              )
              table_report_status(source_db, target_db, table_config)
            when :table_count
              table_count(source_db, target_db, table_config)
            when :table_create_test
              table_create_test(source_db, table_config)
            when :table_fuzz
              table_fuzz(source_db, table_config, @strategy.fuzz_intensity)
            end
          end
        end
      end
    end

    EventMachine.stop_event_loop
  end
end

#log(message) ⇒ Object 



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# File 'lib/tableflip/executor.rb', line 13

def log(message)
  puts "[%s] %s" % [ Time.now.strftime(@time_format), message ]
end

#table_create_test(db, table_config) ⇒ Object 



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# File 'lib/tableflip/executor.rb', line 397

def table_create_test(db, table_config)
  table = table_config[:table]

  do_query(db, "CREATE TABLE `#{table}` (id INT PRIMARY KEY AUTO_INCREMENT, name VARCHAR(255), created_at DATETIME, updated_at DATETIME)")
rescue Mysql2::Error => e
  puts e.to_s
end

#table_exists?(db, table) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tableflip/executor.rb', line 210

def table_exists?(db, table)
  do_query(db, "SHOW FIELDS FROM `#{table}`")

  true

rescue Mysql2::Error
  false
end

#table_fuzz(db, table_config, count) ⇒ Object 



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# File 'lib/tableflip/executor.rb', line 405

def table_fuzz(db, table_config, count)
  require 'securerandom'

  table = table_config[:table]

  EventMachine::PeriodicTimer.new(1) do
    unless (@inserting)
      @inserting = true

      Fiber.new do
        now = Time.now.utc.strftime('%Y-%m-%d %H:%M:%S')

        log("Adding #{count} rows to #{table}")

        count.times do
          do_query(db,
            "INSERT IGNORE INTO `#{table}` (id, name, created_at, updated_at) VALUES (?, ?, ?, ?) ON DUPLICATE KEY UPDATE name=VALUES(name), updated_at=VALUES(updated_at)",
            SecureRandom.random_number(1<<20),
            SecureRandom.hex,
            now,
            now
          )
        end

        @inserting = false
      end.resume
    end
  end
end

#table_migrate(source_db, target_db, table_config) ⇒ Object 



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# File 'lib/tableflip/executor.rb', line 299

def table_migrate(source_db, target_db, table_config)
  table = table_config[:table]
  changes_table = "#{table}__changes"

  result = do_query(source_db, "SELECT COUNT(*) AS rows FROM `#{changes_table}` WHERE claim IS NULL")
  count = table_config[:count] = result.first[:rows]

  log("#{table} has #{table_config[:count]} records to migrate.")

  next_claim = do_query(source_db, "SELECT MAX(claim) AS claim FROM `#{changes_table}`").first[:claim] || 0

  result = do_query(source_db, "SHOW FIELDS FROM `#{table}`")

  exclusions = Hash[
    @strategy.exclude_columns.collect do |column|
      [ column.to_sym, true ]
    end
  ]

  columns = [ ]
  binary_columns = { }

  result.each do |r|
    column = r[:Field].to_sym

    next if (exclusions[column])

    columns << column

    case (r[:Type].downcase)
    when 'tinyblob','blob','mediumblob','longblob','binary','varbinary'
      binary_columns[column] = true
    end
  end

  if (binary_columns.any?)
    log("#{table} has binary columns: #{binary_columns.keys.join(',')}")
  end

  @migrating ||= { }

  fiber = Fiber.current
  migrated = 0
  selected = 1

  loop do
    next_claim += 1
    do_query(source_db, "UPDATE `#{changes_table}` SET claim=? WHERE claim IS NULL LIMIT ?", next_claim, @strategy.block_size)

    result = do_query(source_db, "SELECT id FROM `#{changes_table}` WHERE claim=?", next_claim)

    id_block = result.to_a.collect { |r| r[:id] }

    if (id_block.length == 0)
      if (@strategy.persist?)
        EventMachine::Timer.new(1) do
          fiber.resume
        end

        Fiber.yield

        next
      else
        break
      end
    end

    log("Claim \##{next_claim} yields #{id_block.length} records.")

    selected = do_query(source_db, "SELECT * FROM `#{table}` WHERE id IN (?)", id_block)

    values = selected.collect do |row|
      "(%s)" % [
        escaper(
          source_db,
          columns.collect do |column|
            (binary_columns[column] and row[column]) ? BinaryString.new(row[column]) : row[column]
          end
        )
      ]
    end

    if (values.any?)
      case (@strategy.migrate_method)
      when :insert
        do_query(target_db, "INSERT IGNORE INTO `#{table}` (#{columns.collect { |c| "`#{c}`" }.join(',')}) VALUES #{values.join(',')}")
      else
        do_query(target_db, "REPLACE INTO `#{table}` (#{columns.collect { |c| "`#{c}`" }.join(',')}) VALUES #{values.join(',')}")
      end
    end

    selected = values.length
    migrated += values.length

    log("Migrated %d/%d records for #{table}" % [ migrated, count ])
  end
end

#table_report_status(source_db, target_db, table_config) ⇒ Object 



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# File 'lib/tableflip/executor.rb', line 276

def table_report_status(source_db, target_db, table_config)
  table = table_config[:table]
  changes_table = "#{table}__changes"

  source_table_count = do_query(source_db, "SELECT COUNT(*) AS count FROM `#{table}`").first[:count]
  target_table_count = do_query(target_db, "SELECT COUNT(*) AS count FROM `#{table}`").first[:count]
  migrated_count = do_query(source_db, "SELECT COUNT(*) AS count FROM `#{changes_table}` WHERE claim IS NOT NULL").first[:count]
  tracked_count = do_query(source_db, "SELECT COUNT(*) AS count FROM `#{changes_table}`").first[:count]

  percentage = tracked_count > 0 ? (migrated_count.to_f * 100 / tracked_count) : 0.0

  log(
    "%s: %d/%d [%d/%d] (%.1f%%)" % [
      table,
      source_table_count,
      target_table_count,
      migrated_count,
      tracked_count,
      percentage
    ]
  )
end

#tracking_add(db, table_config) ⇒ Object 



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# File 'lib/tableflip/executor.rb', line 219

def tracking_add(db, table_config)
  table = table_config[:table]
  changes_table = "#{table}__changes"

  if (table_exists?(db, changes_table))
    STDERR.puts("Table #{changes_table} already exists. Not recreated.")
  else
    do_query(db, "CREATE TABLE `#{changes_table}` (id INT PRIMARY KEY, claim INT, INDEX index_claim (claim))")
    do_query(db, "CREATE TRIGGER `#{table}__tai` AFTER INSERT ON `#{table}` FOR EACH ROW INSERT IGNORE INTO `#{changes_table}` (id) VALUES (NEW.id) ON DUPLICATE KEY UPDATE claim=NULL")
    do_query(db, "CREATE TRIGGER `#{table}__tau` AFTER UPDATE ON `#{table}` FOR EACH ROW INSERT IGNORE INTO `#{changes_table}` (id) VALUES (NEW.id) ON DUPLICATE KEY UPDATE claim=NULL")
  end
end

#tracking_remove(db, table_config) ⇒ Object 



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# File 'lib/tableflip/executor.rb', line 232

def tracking_remove(db, table_config)
  table = table_config[:table]
  changes_table = "#{table}__changes"

  if (table_exists?(db, changes_table))
    do_query(db, "DROP TABLE IF EXISTS `#{table}__changes`")
    do_query(db, "DROP TRIGGER IF EXISTS `#{table}__tai`")
    do_query(db, "DROP TRIGGER IF EXISTS `#{table}__tau`")
  else
    STDERR.puts("Table #{changes_table} does not exist. Not removed.")
  end
end

#tracking_seed(db, table_config) ⇒ Object 



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# File 'lib/tableflip/executor.rb', line 245

def tracking_seed(db, table_config)
  table = table_config[:table]
  changes_table = "#{table}__changes"

  result = do_query(db, "SELECT id FROM `#{table}` #{@strategy.where}")

  ids = result.collect { |r| r[:id] }
  GC.start

  if (ids.any?)
    log("Populating #{ids.length} entries into #{changes_table} from #{table}")

    ((ids.length / @strategy.block_size) + 1).times do |n|
      start_offset = @strategy.block_size * n
      id_block = ids[start_offset, @strategy.block_size]

      if (id_block and id_block.any?)
        query = "INSERT IGNORE INTO `#{changes_table}` (id) VALUES %s" % [
          id_block.collect { |id| "(%d)" % id }.join(',')
        ]

        do_query(db, query)

        log("%d/%d entries added to #{changes_table}" % [ start_offset + id_block.length, ids.length ])
      end
    end
  else
    log("No records to migrate from #{table}")
  end
end