Class: Tapsoob::DataStream

Inherits:
Object
  • Object
show all
Defined in:
lib/tapsoob/data_stream.rb

Direct Known Subclasses

DataStreamKeyed

Constant Summary collapse

DEFAULT_CHUNKSIZE = 
1000

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(db, state) ⇒ DataStream

Returns a new instance of DataStream.



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# File 'lib/tapsoob/data_stream.rb', line 11

def initialize(db, state)
  @db = db
  @state = {
    :offset          => 0,
    :avg_chunksize   => 0,
    :num_chunksize   => 0,
    :total_chunksize => 0
  }.merge(state)
  @state[:chunksize] ||= DEFAULT_CHUNKSIZE
  @complete = false
end

Instance Attribute Details

#db ⇒ Object (readonly)

Returns the value of attribute db.



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# File 'lib/tapsoob/data_stream.rb', line 9

def db
  @db
end

#state ⇒ Object (readonly)

Returns the value of attribute state.



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# File 'lib/tapsoob/data_stream.rb', line 9

def state
  @state
end

Class Method Details

.factory(db, state) ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 239

def self.factory(db, state)
  if defined?(Sequel::MySQL) && Sequel::MySQL.respond_to?(:convert_invalid_date_time=)
    Sequel::MySQL.convert_invalid_date_time = :nil
  end

  if state.has_key?(:klass)
    return eval(state[:klass]).new(db, state)
  end

  if Tapsoob::Utils.single_integer_primary_key(db, state[:table_name].to_sym)
    DataStreamKeyed.new(db, state)
  else
    DataStream.new(db, state)
  end
end

.parse_json(json) ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 200

def self.parse_json(json)
  hash = JSON.parse(json).symbolize_keys
  hash[:state].symbolize_keys! if hash.has_key?(:state)
  hash
end

Instance Method Details

#complete? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/tapsoob/data_stream.rb', line 142

def complete?
  @complete
end

#encode_rows(rows) ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 118

def encode_rows(rows)
  Tapsoob::Utils.base64encode(Marshal.dump(rows))
end

#error ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 32

def error
  state[:error] || false
end

#error=(val) ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 28

def error=(val)
  state[:error] = val
end

#fetch(opts = {}) ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 122

def fetch(opts = {})
  opts = (opts.empty? ? { :type => "database", :source => db.uri } : opts)

  log.debug "DataStream#fetch state -> #{state.inspect}"

  t1 = Time.now
  rows = (opts[:type] == "file" ? fetch_file(opts[:source]) : fetch_rows)
  encoded_data = encode_rows(rows)
  t2 = Time.now
  elapsed_time = t2 - t1

  if opts[:type] == "file"
    @complete = rows[:data] == [ ]
  else
    @complete = rows == { }
  end

  [encoded_data, (@complete ? 0 : rows[:data].size), elapsed_time]
end

#fetch_chunksize ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 103

def fetch_chunksize
  chunksize = state[:chunksize]
  return chunksize if state[:num_chunksize] < max_chunksize_training
  return chunksize if state[:avg_chunksize] == 0
  return chunksize if state[:error]
  state[:avg_chunksize] > chunksize ? state[:avg_chunksize] : chunksize
end

#fetch_data_in_database(params) ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 185

def fetch_data_in_database(params)
  encoded_data = params[:encoded_data]

  rows = parse_encoded_data(encoded_data, params[:checksum])

  @complete = rows[:data] == [ ]

  unless @complete
    import_rows(rows)
    rows[:data].size
  else
    0
  end
end

#fetch_database ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 146

def fetch_database
  params = fetch_from_database
  encoded_data = params[:encoded_data]
  json = params[:json]

  rows = parse_encoded_data(encoded_data, json[:checksum])

  @complete = rows == { }

  # update local state
  state.merge!(json[:state].merge(:chunksize => state[:chunksize]))

  unless @complete
    yield rows if block_given?
    state[:offset] += rows[:data].size
    rows[:data].size
  else
    0
  end
end

#fetch_file(dump_path) ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 86

def fetch_file(dump_path)
  state[:chunksize] = fetch_chunksize
  ds = JSON.parse(File.read(File.join(dump_path, "data", "#{table_name}.json")))
  log.debug "DataStream#fetch_file"
  rows = {
    :table_name => ds["table_name"],
    :header     => ds["header"],
    :data       => ds["data"][state[:offset], (state[:offset] + state[:chunksize])] || [ ]
  }
  update_chunksize_stats
  rows
end

#fetch_from_database ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 167

def fetch_from_database
  res = nil
  log.debug "DataStream#fetch_from_database state -> #{state.inspect}"
  state[:chunksize] = Tapsoob::Utils.calculate_chunksize(state[:chunksize]) do |c|
    state[:chunksize] = c.to_i
    encoded_data = fetch.first

    checksum = Tapsoob::Utils.checksum(encoded_data).to_s

    res = {
      :json         => { :checksum => checksum, :state => to_hash },
      :encoded_data => encoded_data
    }
  end

  res
end

#fetch_rows ⇒ Object

keep a record of the average chunksize within the first few hundred thousand records, after chunksize goes below 100 or maybe if offset is > 1000



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# File 'lib/tapsoob/data_stream.rb', line 73

def fetch_rows
  state[:chunksize] = fetch_chunksize
  ds = table.order(*order_by).limit(state[:chunksize], state[:offset])
  log.debug "DataStream#fetch_rows SQL -> #{ds.sql}"
  rows = Tapsoob::Utils.format_data(ds.all,
    :string_columns => string_columns,
    :schema => db.schema(table_name),
    :table => table_name
  )
  update_chunksize_stats
  rows
end

#import_rows(rows) ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 220

def import_rows(rows)
  table.import(rows[:header], rows[:data], :commit_every => 100)
  state[:offset] += rows[:data].size
rescue Exception => ex
  case ex.message
  when /integer out of range/ then
    raise Tapsoob::InvalidData, <<-ERROR, []
  \nDetected integer data that exceeds the maximum allowable size for an integer type.
  This generally occurs when importing from SQLite due to the fact that SQLite does
  not enforce maximum values on integer types.
    ERROR
  else raise ex
  end
end

#increment(row_count) ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 67

def increment(row_count)
  state[:offset] += row_count
end

#log ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 23

def log
  Tapsoob.log.level = Logger::DEBUG if state[:debug]
  Tapsoob.log
end

#max_chunksize_training ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 99

def max_chunksize_training
  20
end

#order_by(name = nil) ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 60

def order_by(name=nil)
  @order_by ||= begin
    name ||= table_name
    Tapsoob::Utils.order_by(db, name)
  end
end

#parse_encoded_data(encoded_data, checksum) ⇒ Object

Raises:



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# File 'lib/tapsoob/data_stream.rb', line 206

def parse_encoded_data(encoded_data, checksum)
  raise Tapsoob::CorruptedData.new("Checksum Failed") unless Tapsoob::Utils.valid_data?(encoded_data, checksum)

  begin
    return Marshal.load(Tapsoob::Utils.base64decode(encoded_data))
  rescue Object => e
    unless ENV['NO_DUMP_MARSHAL_ERRORS']
      puts "Error encountered loading data, wrote the data chunk to dump.#{Process.pid}.dat"
      File.open("dump.#{Process.pid}.dat", "w") { |f| f.write(encoded_data) }
    end
    raise e
  end
end

#string_columns ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 52

def string_columns
  @string_columns ||= Tapsoob::Utils.incorrect_blobs(db, table_name)
end

#table ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 56

def table
  @table ||= db[table_name_sql]
end

#table_name ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 36

def table_name
  state[:table_name].to_sym
end

#table_name_sql ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 40

def table_name_sql
  table_name
end

#to_hash ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 44

def to_hash
  state.merge(:klass => self.class.to_s)
end

#to_json ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 48

def to_json
  JSON.generate(to_hash)
end

#update_chunksize_stats ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 111

def update_chunksize_stats
  return if state[:num_chunksize] >= max_chunksize_training
  state[:total_chunksize] += state[:chunksize]
  state[:num_chunksize] += 1
  state[:avg_chunksize] = state[:total_chunksize] / state[:num_chunksize] rescue state[:chunksize]
end

#verify_stream ⇒ Object 



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# File 'lib/tapsoob/data_stream.rb', line 235

def verify_stream
  state[:offset] = table.count
end