Class: Innodb::UndoLog

Inherits:
Object
  • Object
show all
Defined in:
lib/innodb/undo_log.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(page, position) ⇒ UndoLog

Returns a new instance of UndoLog.



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# File 'lib/innodb/undo_log.rb', line 5

def initialize(page, position)
  @page = page
  @position = position
end

Instance Attribute Details

#page ⇒ Object (readonly)

Returns the value of attribute page.



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# File 'lib/innodb/undo_log.rb', line 3

def page
  @page
end

#position ⇒ Object (readonly)

Returns the value of attribute position.



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# File 'lib/innodb/undo_log.rb', line 4

def position
  @position
end

Instance Method Details

#dump ⇒ Object 



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# File 'lib/innodb/undo_log.rb', line 68

def dump
  puts "header:"
  pp header
  puts
end

#header ⇒ Object 



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# File 'lib/innodb/undo_log.rb', line 56

def header
  undo_log[:header]
end

#next_address ⇒ Object 



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# File 'lib/innodb/undo_log.rb', line 64

def next_address
  header[:history_list_node][:next]
end

#prev_address ⇒ Object 



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# File 'lib/innodb/undo_log.rb', line 60

def prev_address
  header[:history_list_node][:prev]
end

#read_header(cursor) ⇒ Object 



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# File 'lib/innodb/undo_log.rb', line 18

def read_header(cursor)
  cursor.name("header") do |c|
    xid_exists = nil
    {
      :trx_id => c.name("trx_id") { c.get_hex(8) },
      :trx_no => c.name("trx_no") { c.get_uint64 },
      :delete_marks => c.name("delete_marks") { (c.get_uint16 != 0) },
      :log_start => c.name("log_start") { c.get_uint16 },
      :xid_exists => c.name("xid_exists") { xid_exists = (c.get_uint8 != 0) },
      :dict_trans => c.name("dict_trans") { (c.get_uint8 != 0) },
      :table_id => c.name("table_id") { c.get_uint64 },
      :next_log => c.name("next_log") { c.get_uint16 },
      :prev_log => c.name("prev_log") { c.get_uint16 },
      :history_list_node => c.name("history_list_node") {
        Innodb::List.get_node(c)
      },
      :xid => c.name("xid") {
        if xid_exists
          {
            :format => c.name("format") { c.get_uint32 },
            :trid_len => c.name("trid_len") { c.get_uint32 },
            :bqual_len => c.name("bqual_len") { c.get_uint32 },
            :data => c.name("data") { c.get_bytes(128) },
          }
        end
      },
    }
  end
end

#size_header ⇒ Object 



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# File 'lib/innodb/undo_log.rb', line 14

def size_header
  8 + 8 + 2 + 2 + 1 + 1 + 8 + 2 + 2 + Innodb::List::NODE_SIZE + size_xa_header
end

#size_xa_header ⇒ Object 



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# File 'lib/innodb/undo_log.rb', line 10

def size_xa_header
  4 + 4 + 4 + 128
end

#undo_log ⇒ Object 



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# File 'lib/innodb/undo_log.rb', line 48

def undo_log
  @undo_log ||= page.cursor(position).name("undo_log") do |c|
    {
      :header => read_header(c),
    }
  end
end