Class: Innodb::IbufBitmap

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

Defined Under Namespace

Classes: PageStatus

Constant Summary collapse

BITS_PER_PAGE = 
4
BITMAP_BV_FREE = 
1 + 2
BITMAP_BV_BUFFERED = 
4
BITMAP_BV_IBUF = 
8
BITMAP_BV_ALL = 
BITMAP_BV_FREE |
BITMAP_BV_BUFFERED |
BITMAP_BV_IBUF

Instance Method Summary collapse

Constructor Details

#initialize(page, cursor) ⇒ IbufBitmap

Returns a new instance of IbufBitmap.



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

def initialize(page, cursor)
  @page = page
  @bitmap = read_bitmap(cursor)
end

Instance Method Details

#each_page_status ⇒ Object 



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# File 'lib/innodb/ibuf_bitmap.rb', line 31

def each_page_status
  return enum_for(:each_page_status) unless block_given?

  bitmap = @bitmap.enum_for(:each_byte)

  bitmap.each_with_index do |byte, byte_index|
    (0..1).each do |page_offset|
      page_number = (byte_index * 2) + page_offset
      page_bits = ((byte >> (page_offset * BITS_PER_PAGE)) & BITMAP_BV_ALL)
      page_status = PageStatus.new(
        free: (page_bits & BITMAP_BV_FREE),
        buffered: (page_bits & BITMAP_BV_BUFFERED != 0),
        ibuf: (page_bits & BITMAP_BV_IBUF != 0)
      )
      yield page_number, page_status
    end
  end
end

#read_bitmap(cursor) ⇒ Object 



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# File 'lib/innodb/ibuf_bitmap.rb', line 27

def read_bitmap(cursor)
  cursor.name("ibuf_bitmap") { |c| c.read_bytes(size_bitmap) }
end

#size_bitmap ⇒ Object 



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# File 'lib/innodb/ibuf_bitmap.rb', line 23

def size_bitmap
  (@page.space.pages_per_bookkeeping_page * BITS_PER_PAGE) / 8
end