Class: Innodb::Page::FspHdrXdes

Inherits:
Innodb::Page show all
Extended by:
ReadBitsAtOffset
Defined in:
lib/innodb/page/fsp_hdr_xdes.rb

Defined Under Namespace

Classes: Flags, Header

Constant Summary collapse

FLAGS_PAGE_SIZE_SHIFT =

A value added to the adjusted exponent stored in the page size field of the flags in the FSP header.

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Constants inherited from Innodb::Page

PAGE_TYPE, PAGE_TYPE_BY_VALUE, UNDEFINED_PAGE_NUMBER

Instance Attribute Summary

Attributes inherited from Innodb::Page

#space

Class Method Summary collapse

Instance Method Summary collapse

Methods included from ReadBitsAtOffset

read_bits_at_offset

Methods inherited from Innodb::Page

#checksum_crc32, #checksum_crc32?, #checksum_innodb, #checksum_innodb?, #checksum_invalid?, #checksum_type, #checksum_valid?, #corrupt?, #cursor, #default_page_size?, #each_page_body_byte_as_uint8, #each_page_header_byte_as_uint8, #extent_descriptor?, #fil_header, #fil_trailer, handle, #in_doublewrite_buffer?, #initialize, #inspect, #inspect_header_fields, maybe_undefined, #misplaced?, #misplaced_offset?, #misplaced_space?, #name, parse, #pos_fil_header, #pos_fil_trailer, #pos_page_body, #pos_partial_page_header, register_specialization, #size, #size_fil_header, #size_fil_trailer, #size_page_body, #size_partial_page_header, specialization_for, specialization_for?, #torn?, undefined?

Constructor Details

This class inherits a constructor from Innodb::Page

Class Method Details

.decode_flags(flags) ⇒ Object

Decode the “flags” field in the FSP header, returning a hash of useful decodings of the flags (based on MySQl 5.6 definitions). The flags are:

Offset Size Description 0 1 Post-Antelope Flag. 1 4 Compressed Page Size (zip_size). This is stored as a

power of 2, minus 9. Since 0 is reserved to mean "not
compressed", the minimum value is 1, thus making the
smallest page size 1024 (2 ** (9 + 1)).

5 1 Atomic Blobs Flag. 6 4 System Page Size (innodb_page_size, UNIV_PAGE_SIZE).

The setting of the system page size when the tablespace
was created, stored in the same format as the compressed
page size above.

10 1 Data Directory Flag.



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# File 'lib/innodb/page/fsp_hdr_xdes.rb', line 74

def self.decode_flags(flags)
  system_page_size =
    shift_page_size(read_bits_at_offset(flags, 4, 6)) ||
    Innodb::Space::DEFAULT_PAGE_SIZE
  compressed_page_size = shift_page_size(read_bits_at_offset(flags, 4, 1))

  Flags.new(
    system_page_size: system_page_size,
    compressed: compressed_page_size ? false : true,
    page_size: compressed_page_size || system_page_size,
    post_antelope: read_bits_at_offset(flags, 1, 0) == 1,
    atomic_blobs: read_bits_at_offset(flags, 1, 5) == 1,
    data_directory: read_bits_at_offset(flags, 1, 10) == 1,
    value: flags
  )
end

.shift_page_size(page_size_shifted) ⇒ Object 



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# File 'lib/innodb/page/fsp_hdr_xdes.rb', line 54

def self.shift_page_size(page_size_shifted)
  (1 << (FLAGS_PAGE_SIZE_SHIFT + page_size_shifted)) if page_size_shifted != 0
end

Instance Method Details

#dump ⇒ Object

Dump the contents of a page for debugging purposes.



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# File 'lib/innodb/page/fsp_hdr_xdes.rb', line 191

def dump
  super

  puts "fsp header:"
  pp fsp_header
  puts

  puts "xdes entries:"
  each_xdes do |xdes|
    pp xdes
  end
  puts
end

#each_list ⇒ Object

Iterate through all lists in the file space.



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# File 'lib/innodb/page/fsp_hdr_xdes.rb', line 143

def each_list
  return enum_for(:each_list) unless block_given?

  fsp_header.to_h.each do |key, value|
    yield key, value if value.is_a?(Innodb::List)
  end
end

#each_region {|Region.new( offset: pos_fsp_header, length: size_fsp_header, name: :fsp_header, info: "FSP Header" )| ... } ⇒ Object

Yields:



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# File 'lib/innodb/page/fsp_hdr_xdes.rb', line 165

def each_region(&block)
  return enum_for(:each_region) unless block_given?

  super(&block)

  yield Region.new(
    offset: pos_fsp_header,
    length: size_fsp_header,
    name: :fsp_header,
    info: "FSP Header"
  )

  each_xdes do |xdes|
    state = xdes.state || "unused"
    yield Region.new(
      offset: xdes.offset,
      length: size_xdes_entry,
      name: "xdes_#{state}".to_sym,
      info: "Extent Descriptor (#{state})"
    )
  end

  nil
end

#each_xdes ⇒ Object

Iterate through all XDES entries in order. This is useful for debugging, but each of these entries is actually a node in some other list. The state field in the XDES entry indicates which type of list it is present in, although not necessarily which list (e.g. :fseg).



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# File 'lib/innodb/page/fsp_hdr_xdes.rb', line 155

def each_xdes
  return enum_for(:each_xdes) unless block_given?

  cursor(pos_xdes_array).name("xdes_array") do |c|
    entries_in_xdes_array.times do
      yield Innodb::Xdes.new(self, c)
    end
  end
end

#entries_in_xdes_array ⇒ Object

The number of entries in the XDES array. Defined as page size divided by extent size.



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# File 'lib/innodb/page/fsp_hdr_xdes.rb', line 109

def entries_in_xdes_array
  size / space.pages_per_extent
end

#fsp_header ⇒ Object

Read the FSP (filespace) header, which contains a few counters and flags, as well as list base nodes for each list maintained in the filespace.



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# File 'lib/innodb/page/fsp_hdr_xdes.rb', line 123

def fsp_header
  @fsp_header ||= cursor(pos_fsp_header).name("fsp") do |c|
    Header.new(
      space_id: c.name("space_id") { c.read_uint32 },
      unused: c.name("unused") { c.read_uint32 },
      size: c.name("size") { c.read_uint32 },
      free_limit: c.name("free_limit") { c.read_uint32 },
      flags: c.name("flags") { self.class.decode_flags(c.read_uint32) },
      frag_n_used: c.name("frag_n_used") { c.read_uint32 },
      free: c.name("list[free]") { Innodb::List::Xdes.new(@space, Innodb::List.get_base_node(c)) },
      free_frag: c.name("list[free_frag]") { Innodb::List::Xdes.new(@space, Innodb::List.get_base_node(c)) },
      full_frag: c.name("list[full_frag]") { Innodb::List::Xdes.new(@space, Innodb::List.get_base_node(c)) },
      first_unused_seg: c.name("first_unused_seg") { c.read_uint64 },
      full_inodes: c.name("list[full_inodes]") { Innodb::List::Inode.new(@space, Innodb::List.get_base_node(c)) },
      free_inodes: c.name("list[free_inodes]") { Innodb::List::Inode.new(@space, Innodb::List.get_base_node(c)) }
    )
  end
end

#pos_fsp_header ⇒ Object

The FSP header immediately follows the FIL header.



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# File 'lib/innodb/page/fsp_hdr_xdes.rb', line 92

def pos_fsp_header
  pos_page_body
end

#pos_xdes_array ⇒ Object

The XDES entry array immediately follows the FSP header.



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# File 'lib/innodb/page/fsp_hdr_xdes.rb', line 103

def pos_xdes_array
  pos_fsp_header + size_fsp_header
end

#size_fsp_header ⇒ Object

The FSP header contains six 32-bit integers, one 64-bit integer, and 5 list base nodes.



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# File 'lib/innodb/page/fsp_hdr_xdes.rb', line 98

def size_fsp_header
  ((4 * 6) + (1 * 8) + (5 * Innodb::List::BASE_NODE_SIZE))
end

#size_xdes_array ⇒ Object 



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# File 'lib/innodb/page/fsp_hdr_xdes.rb', line 117

def size_xdes_array
  entries_in_xdes_array * size_xdes_entry
end

#size_xdes_entry ⇒ Object 



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# File 'lib/innodb/page/fsp_hdr_xdes.rb', line 113

def size_xdes_entry
  @size_xdes_entry ||= Innodb::Xdes.new(self, cursor(pos_xdes_array)).size_entry
end