Class: Innodb::Page::TrxSys

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

Defined Under Namespace

Classes: DoublewriteInfo, DoublewritePageInfo, Header, MysqlLogInfo, RsegSlot

Constant Summary collapse

MYSQL_LOG_MAGIC_N =

A magic number present in each MySQL binary log information structure, which helps identify whether the structure is populated or not.

873_422_344
DOUBLEWRITE_MAGIC_N =

A magic number present in each doublewrite buffer information structure, which helps identify whether the structure is populated or not.

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DOUBLEWRITE_SPACE_ID_STORED_MAGIC_N =

A magic number present in the overall doublewrite buffer structure, which identifies whether the space id is stored.

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N_RSEGS = 
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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

Instance Method Summary collapse

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, page_type_by_value, 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

Instance Method Details

#doublewrite_info(cursor) ⇒ Object

Read the overall doublewrite buffer structures



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# File 'lib/innodb/page/trx_sys.rb', line 149

def doublewrite_info(cursor)
  cursor.peek(pos_doublewrite_info) do |c_doublewrite|
    c_doublewrite.name("doublewrite") do |c|
      DoublewriteInfo.new(
        fseg: c.name("fseg") { Innodb::FsegEntry.get_inode(@space, c) },
        page_info: [0, 1].map { |n| c.name("group[#{n}]") { doublewrite_page_info(c) } },
        space_id_stored: (c.name("space_id_stored") { c.read_uint32 } == DOUBLEWRITE_SPACE_ID_STORED_MAGIC_N)
      )
    end
  end
end

#doublewrite_page_info(cursor) ⇒ Object

Read a single doublewrite buffer information structure from a given cursor.



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# File 'lib/innodb/page/trx_sys.rb', line 139

def doublewrite_page_info(cursor)
  magic_n = cursor.name("magic_n") { cursor.read_uint32 }

  DoublewritePageInfo.new(
    magic_n: magic_n,
    page_number: [0, 1].map { |n| cursor.name("page[#{n}]") { cursor.read_uint32 } }
  )
end

#dump ⇒ Object

Dump the contents of a page for debugging purposes.



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# File 'lib/innodb/page/trx_sys.rb', line 228

def dump
  super

  puts "trx_sys:"
  pp trx_sys
  puts
end

#each_region {|Region.new( offset: pos_trx_sys_header, length: size_trx_sys_header, name: :trx_sys_header, info: "Transaction System Header" )| ... } ⇒ Object

Yields:



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# File 'lib/innodb/page/trx_sys.rb', line 182

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

  super

  yield Region.new(
    offset: pos_trx_sys_header,
    length: size_trx_sys_header,
    name: :trx_sys_header,
    info: "Transaction System Header"
  )

  rsegs.each do |rseg|
    yield Region.new(
      offset: rseg[:offset],
      length: 4 + 4,
      name: :rseg,
      info: "Rollback Segment"
    )
  end

  yield Region.new(
    offset: pos_mysql_binary_log_info,
    length: size_mysql_log_info,
    name: :mysql_binary_log_info,
    info: "Binary Log Info"
  )

  yield Region.new(
    offset: pos_mysql_master_log_info,
    length: size_mysql_log_info,
    name: :mysql_master_log_info,
    info: "Master Log Info"
  )

  yield Region.new(
    offset: pos_doublewrite_info,
    length: size_doublewrite_info,
    name: :doublewrite_info,
    info: "Double Write Buffer Info"
  )

  nil
end

#mysql_log_info(cursor, offset) ⇒ Object

Read a MySQL binary log information structure from a given position.



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# File 'lib/innodb/page/trx_sys.rb', line 125

def mysql_log_info(cursor, offset)
  cursor.peek(offset) do |c|
    magic_n = c.name("magic_n") { c.read_uint32 } == MYSQL_LOG_MAGIC_N
    break unless magic_n

    MysqlLogInfo.new(
      magic_n: magic_n,
      offset: c.name("offset") { c.read_uint64 },
      name: c.name("name") { c.read_bytes(100) }
    )
  end
end

#pos_doublewrite_info ⇒ Object

The doublewrite buffer information is located 200 bytes from the end of the page.



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# File 'lib/innodb/page/trx_sys.rb', line 89

def pos_doublewrite_info
  size - 200
end

#pos_mysql_binary_log_info ⇒ Object

The local binary log information is located 1000 bytes from the end of the page.



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# File 'lib/innodb/page/trx_sys.rb', line 83

def pos_mysql_binary_log_info
  size - 1_000
end

#pos_mysql_master_log_info ⇒ Object

The master’s binary log information is located 2000 bytes from the end of the page.



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# File 'lib/innodb/page/trx_sys.rb', line 77

def pos_mysql_master_log_info
  size - 2_000
end

#pos_rsegs_array ⇒ Object 



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# File 'lib/innodb/page/trx_sys.rb', line 67

def pos_rsegs_array
  pos_trx_sys_header + size_trx_sys_header
end

#pos_trx_sys_header ⇒ Object

The TRX_SYS header immediately follows the FIL header.



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# File 'lib/innodb/page/trx_sys.rb', line 59

def pos_trx_sys_header
  pos_page_body
end

#rsegs_array(cursor) ⇒ Object 



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# File 'lib/innodb/page/trx_sys.rb', line 111

def rsegs_array(cursor)
  @rsegs_array ||= N_RSEGS.times.each_with_object([]) do |n, a|
    cursor.name("slot[#{n}]") do |c|
      slot = RsegSlot.new(
        offset: c.position,
        space_id: c.name("space_id") { Innodb::Page.maybe_undefined(c.read_uint32) },
        page_number: c.name("page_number") { Innodb::Page.maybe_undefined(c.read_uint32) }
      )
      a << slot if slot.space_id && slot.page_number
    end
  end
end

#size_doublewrite_info ⇒ Object 



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# File 'lib/innodb/page/trx_sys.rb', line 93

def size_doublewrite_info
  Innodb::FsegEntry::SIZE + (2 * (4 + 4 + 4)) + 4
end

#size_mysql_log_info ⇒ Object 



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# File 'lib/innodb/page/trx_sys.rb', line 71

def size_mysql_log_info
  4 + 8 + 100
end

#size_trx_sys_header ⇒ Object 



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# File 'lib/innodb/page/trx_sys.rb', line 63

def size_trx_sys_header
  8 + Innodb::FsegEntry::SIZE
end

#trx_sys ⇒ Object

Read the TRX_SYS headers and other information.



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# File 'lib/innodb/page/trx_sys.rb', line 162

def trx_sys
  @trx_sys ||= cursor(pos_trx_sys_header).name("trx_sys") do |c|
    Header.new(
      trx_id: c.name("trx_id") { c.read_uint64 },
      fseg: c.name("fseg") { Innodb::FsegEntry.get_inode(@space, c) },
      rsegs: c.name("rsegs") { rsegs_array(c) },
      binary_log: c.name("binary_log") { mysql_log_info(c, pos_mysql_binary_log_info) },
      master_log: c.name("master_log") { mysql_log_info(c, pos_mysql_master_log_info) },
      doublewrite: doublewrite_info(c)
    )
  end
end