Doublewrite implementation. More...

Inheritance diagram for Double_write:

Classes
struct	Buf_pages
	For collecting pages to write. More...

Public Member Functions
	Double_write (uint16_t id, uint32_t n_pages) noexcept
	Constructor. More...

virtual	~Double_write () noexcept
	Destructor. More...

uint16_t	id () const noexcept

void	write (buf_flush_t flush_type) noexcept
	Process the requests in the flush queue, write the blocks to the double write file, sync the file if required and then write to the data files. More...

bool	wait_for_pending_batch () noexcept
	Wait for any pending batch to complete. More...

bool	flush_to_disk (buf_flush_t flush_type) noexcept
	Flush buffered pages to disk, clear the buffers. More...

void	write_pages (buf_flush_t flush_type) noexcept
	Process the requests in the flush queue, write the blocks to the double write file, sync the file if required and then issue asynchronous writes to the data files. More...

virtual uint16_t	write_dblwr_pages (buf_flush_t flush_type) noexcept

void	write_data_pages (buf_flush_t flush_type, uint16_t batch_id) noexcept

void	force_flush (buf_flush_t flush_type) noexcept
	Force a flush of the page queue. More...

void	enqueue (buf_flush_t flush_type, buf_page_t bpage, const file::Block e_block) noexcept
	Add a page to the flush batch. More...

void	batch_started () noexcept
	Note that the IO batch has started. More...

void	batch_completed () noexcept
	Wake up all the threads that were waiting for the batch to complete. More...

	Double_write (const Double_write &)=delete

	Double_write (Double_write &&)=delete

Double_write &	operator= (Double_write &&)=delete

Double_write &	operator= (const Double_write &)=delete

Static Public Member Functions
static Double_write *	instance (buf_flush_t flush_type, uint32_t buf_pool_index, bool is_reduced) noexcept

static dberr_t	create_batch_segments (uint32_t segments_per_file) noexcept
	Create the batch write segments. More...

static dberr_t	create_reduced_batch_segments () noexcept
	Create the Reduced batch write segments. More...

static dberr_t	create_single_segments () noexcept
	Create the single page flush segments. More...

static void	submit (buf_flush_t flush_type, buf_page_t bpage, const file::Block e_block) noexcept
	Get the instance that handles a particular page's IO. More...

static dberr_t	sync_page_flush (buf_page_t bpage, file::Block e_block) noexcept
	Writes a single page to the doublewrite buffer on disk, syncs it, then writes the page to the datafile. More...

static Double_write *	instance (buf_flush_t flush_type, const buf_page_t *bpage) noexcept

static void	write_complete (buf_page_t *bpage, buf_flush_t flush_type) noexcept
	Updates the double write buffer when a write request is completed. More...

static bool	init_v1 (page_no_t &block1, page_no_t &block2) noexcept
	REad the V1 doublewrite buffer extents boundaries. More...

static bool	create_v1 (page_no_t &block1, page_no_t &block2) noexcept
	Creates the V1 doublewrite buffer extents. More...

static dberr_t	write_to_datafile (const buf_page_t in_bpage, bool sync, const file::Block e_block, std::function< void(dberr_t err)> pre_io_complete_callback) noexcept
	Writes a page that has already been written to the doublewrite buffer to the data file. More...

static void	force_flush (buf_flush_t flush_type, uint32_t buf_pool_index) noexcept
	Force a flush of the page queue. More...

static dberr_t	load (dblwr::File &file, recv::Pages *pages) noexcept
	Load the doublewrite buffer pages from an external file. More...

static dberr_t	load_reduced_batch (dblwr::File &file, recv::Pages *pages) noexcept
	Load the reduced doublewrite buffer page entries from an reduced batch double write buffer file (.bdblwr) More...

static dberr_t	init_file (dblwr::File &file, uint32_t n_pages, uint32_t phy_size=univ_page_size.physical()) noexcept
	Write zeros to the file if it is "empty". More...

static void	reset_file (dblwr::File &file, bool truncate) noexcept
	Reset the size in bytes to the configured size. More...

static void	reduced_reset_file (dblwr::File &file, uint32_t pages_per_file, uint32_t phy_size) noexcept
	Reset the size in bytes to the configured size. More...

static void	reset_files () noexcept
	Reset the size in bytes to the configured size of all files. More...

static dberr_t	create_v2 () noexcept
	Create the v2 data structures. More...

static dberr_t	create_reduced () noexcept
	Create the data structures for reduced doublewrite buffer. More...

static bool	is_fsync_required () noexcept

static void	prepare (const buf_page_t bpage, byte ptr, uint32_t len) noexcept
	Extract the data and length to write to the doublewrite file. More...

static void	shutdown () noexcept
	Free the data structures. More...

static void	toggle (ulong value) noexcept
	Toggle the doublewrite buffer dynamically. More...

static void	single_write (Segment segment, const buf_page_t bpage, file::Block *e_block) noexcept
	Write the data to disk synchronously. More...

Public Attributes
unsigned long long	m_bytes_written {}
	Number of bytes written to disk by this instance. More...

Static Public Attributes
static uint32_t	s_n_instances {}
	Number of instances. More...

static std::vector< dblwr::File >	s_files
	Files to use for atomic writes. More...

static std::vector< dblwr::File >	s_r_files
	Reduced batch doublewrite files to use for atomic writes. More...

static Instances *	s_instances {}
	The global instances. More...

static Instances *	s_r_instances {}
	The global Reduced Doublewrite instances. More...

Protected Types
using	Segments = mpmc_bq< Segment * >

using	Instances = std::vector< Double_write * >

using	Batch_segments = mpmc_bq< Batch_segment * >

Static Protected Member Functions
static void	free_segments (Batch_segments *&segments) noexcept
	Utility function to free batch segments. More...

static bool	is_reduced_batch_id (uint32_t batch_id)

Protected Attributes
uint16_t	m_id {}
	Instance ID. More...

ib_mutex_t	m_mutex
	Protects m_buf_pages. More...

os_event_t	m_event
	Wait for IO batch to complete. More...

std::atomic_bool	m_batch_running {false}
	true if the batch hasn't completed yet. More...

Buffer	m_buffer
	The copy of the page frame, the page must be in in m_buf_pages. More...

Buf_pages	m_buf_pages
	Pages that should be written to the data files. More...

Static Protected Attributes
static Batch_segments *	s_LRU_batch_segments {}
	File segments to use for LRU batched writes. More...

static Batch_segments *	s_flush_list_batch_segments {}
	File segments to use for flush list batched writes. More...

static Segments *	s_single_segments {}
	File segments to use for single page writes. More...

static Batch_segments *	s_r_LRU_batch_segments {}
	File segments to use for LRU batched writes in reduced dblwr mode. More...

static Batch_segments *	s_r_flush_list_batch_segments {}
	File segments to use for flush list batched writes (reduced mode) More...

static std::vector< Batch_segment * >	s_segments {}
	For indexing batch segments by ID. More...

static uint32_t	s_regular_last_batch_id {}
	Last used batch_id for regular batch segments. More...

Static Private Member Functions
static dberr_t	start () noexcept
	Create the singleton instance, start the flush thread. More...

static void	croak (const buf_block_t *block) noexcept
	Asserts when a corrupt block is found during writing out data to the disk. More...

static void	check_block (const buf_block_t *block) noexcept
	Check the LSN values on the page with which this block is associated. More...

static void	check_page_lsn (const page_t *page) noexcept
	Check the LSN values on the page. More...

static byte *	get (mtr_t *mtr) noexcept
	Calls buf_page_get() on the TRX_SYS_PAGE and returns a pointer to the doublewrite buffer within it. More...

Detailed Description

Doublewrite implementation.

Assumes it can use DBLWR_PAGES.

Member Typedef Documentation

◆ Batch_segments

using Double_write::Batch_segments = mpmc_bq<Batch_segment *>

protected

◆ Instances

using Double_write::Instances = std::vector<Double_write *>

protected

◆ Segments

using Double_write::Segments = mpmc_bq<Segment *>

protected

Constructor & Destructor Documentation

◆ Double_write() [1/3]

Double_write::Double_write	(	uint16_t	id,
		uint32_t	n_pages
	)

noexcept

Constructor.

Parameters

[in]	id	Instance ID
[in]	n_pages	Number of pages handled by this instance.

◆ ~Double_write()

Double_write::~Double_write ( )

virtualnoexcept

Destructor.

◆ Double_write() [2/3]

Double_write::Double_write ( const Double_write & )

delete

◆ Double_write() [3/3]

Double_write::Double_write ( Double_write && )

delete

Member Function Documentation

◆ batch_completed()

void Double_write::batch_completed ( )

inlinenoexcept

Wake up all the threads that were waiting for the batch to complete.

◆ batch_started()

void Double_write::batch_started ( )

inlinenoexcept

Note that the IO batch has started.

◆ check_block()

void Double_write::check_block ( const buf_block_t * block )

staticprivatenoexcept

Check the LSN values on the page with which this block is associated.

Also validate the page if the option is set.

Parameters

[in] block Block to check

◆ check_page_lsn()

void Double_write::check_page_lsn ( const page_t * page )

staticprivatenoexcept

Check the LSN values on the page.

Parameters

[in] page Page to check

◆ create_batch_segments()

dberr_t Double_write::create_batch_segments ( uint32_t segments_per_file )

staticnoexcept

Create the batch write segments.

Parameters

[in] segments_per_file Number of configured segments per file.

Returns: DB_SUCCESS or error code.

◆ create_reduced()

dberr_t Double_write::create_reduced ( )

staticnoexcept

Create the data structures for reduced doublewrite buffer.

Returns: DB_SUCCESS or error code

◆ create_reduced_batch_segments()

dberr_t Double_write::create_reduced_batch_segments ( )

staticnoexcept

Create the Reduced batch write segments.

These segments are mapped to separate file which has extension .bdblwr

Returns: DB_SUCCESS or error code.

◆ create_single_segments()

dberr_t Double_write::create_single_segments ( )

staticnoexcept

Create the single page flush segments.

Returns: DB_SUCCESS or error code.

◆ create_v1()

bool Double_write::create_v1	(	page_no_t &	block1,
		page_no_t &	block2
	)

staticnoexcept

Creates the V1 doublewrite buffer extents.

The header of the doublewrite buffer is placed on the trx system header page.

Parameters

[in,out]	block1	Starting block number for the first extent.
[in,out]	block2	Starting block number for the second extent.

Returns: true if successful, false if not.

◆ create_v2()

dberr_t Double_write::create_v2 ( )

staticnoexcept

Create the v2 data structures.

Returns: DB_SUCCESS or error code

◆ croak()

void Double_write::croak ( const buf_block_t * block )

staticprivatenoexcept

Asserts when a corrupt block is found during writing out data to the disk.

Parameters

[in] block Block that was corrupt

◆ enqueue()

void Double_write::enqueue	(	buf_flush_t	flush_type,
		buf_page_t *	bpage,
		const file::Block *	e_block
	)

inlinenoexcept

Add a page to the flush batch.

If the flush batch is full then write the batch to disk.

Parameters

[in]	flush_type	Flush type.
[in]	bpage	Page to flush to disk.
[in]	e_block	Encrypted block frame or nullptr.

◆ flush_to_disk()

bool Double_write::flush_to_disk ( buf_flush_t flush_type )

inlinenoexcept

Flush buffered pages to disk, clear the buffers.

Parameters

[in] flush_type FLUSH LIST or LRU LIST flush.

Returns: false if there was a write batch already in progress.

◆ force_flush() [1/2]

void Double_write::force_flush ( buf_flush_t flush_type )

inlinenoexcept

Force a flush of the page queue.

Parameters

[in] flush_type FLUSH LIST or LRU LIST flush.

◆ force_flush() [2/2]

static void Double_write::force_flush	(	buf_flush_t	flush_type,
		uint32_t	buf_pool_index
	)

inlinestaticnoexcept

Force a flush of the page queue.

Parameters

[in]	flush_type	FLUSH LIST or LRU LIST flush.
[in]	buf_pool_index	Buffer pool instance for which called.

◆ free_segments()

void Double_write::free_segments ( Batch_segments *& segments )

staticprotectednoexcept

Utility function to free batch segments.

Parameters

[in] segments batch segment to free

◆ get()

byte * Double_write::get ( mtr_t * mtr )

staticprivatenoexcept

Calls buf_page_get() on the TRX_SYS_PAGE and returns a pointer to the doublewrite buffer within it.

Parameters

[in,out] mtr To manage the page latches

Returns: pointer to the doublewrite buffer within the filespace header page.

◆ id()

uint16_t Double_write::id ( ) const

inlinenoexcept

Returns: instance ID

◆ init_file()

dberr_t Double_write::init_file	(	dblwr::File &	file,
		uint32_t	n_pages,
		uint32_t	phy_size = `univ_page_size.physical()`
	)

staticnoexcept

Write zeros to the file if it is "empty".

Parameters

[in]	file	File instance.
[in]	n_pages	Size in physical pages.
[in]	phy_size	Physical page size in DBLWR file (For reduced DBLW file, it is not UNIV_PAGE_SIZE, it is hardcoded to 8K page size)

Returns: DB_SUCCESS or error code

◆ init_v1()

bool Double_write::init_v1	(	page_no_t &	block1,
		page_no_t &	block2
	)

staticnoexcept

REad the V1 doublewrite buffer extents boundaries.

Parameters

[in,out]	block1	Starting block number for the first extent.
[in,out]	block2	Starting block number for the second extent.

Returns: true if successful, false if not.

◆ instance() [1/2]

static Double_write * Double_write::instance	(	buf_flush_t	flush_type,
		const buf_page_t *	bpage
	)

inlinestaticnoexcept

Returns: the double write instance to use for flushing.

Parameters

[in]	flush_type	LRU or Flush list write.
[in]	bpage	Page to write to disk.

Returns: instance that will handle the flush to disk.

◆ instance() [2/2]

static Double_write * Double_write::instance	(	buf_flush_t	flush_type,
		uint32_t	buf_pool_index,
		bool	is_reduced
	)

inlinestaticnoexcept

Returns: the double write instance to use for flushing.

Parameters

[in]	buf_pool_index	Buffer pool instance number.
[in]	flush_type	LRU or Flush list write.
[in]	is_reduced	true if reduced mode of dblwr is being used.

Returns: instance that will handle the flush to disk.

◆ is_fsync_required()

static bool Double_write::is_fsync_required ( )

inlinestaticnoexcept

Returns: true if we need to fsync to disk

◆ is_reduced_batch_id()

bool Double_write::is_reduced_batch_id ( uint32_t batch_id )

staticprotected

Returns: true if batch belonged to reduced dblwr. When returning a batch segment to lock-free queue, we should know which lock-free queue(Batch_segments) to return to

Parameters

[in] batch_id Batch segment id

◆ load()

dberr_t Double_write::load	(	dblwr::File &	file,
		recv::Pages *	pages
	)

staticnoexcept

Load the doublewrite buffer pages from an external file.

Parameters

[in,out]	file	File handle
[in,out]	pages	For storing the doublewrite pages read from the file

Returns: DB_SUCCESS or error code

◆ load_reduced_batch()

dberr_t Double_write::load_reduced_batch	(	dblwr::File &	file,
		recv::Pages *	pages
	)

staticnoexcept

Load the reduced doublewrite buffer page entries from an reduced batch double write buffer file (.bdblwr)

Parameters

[in,out]	file	File handle
[in,out]	pages	For storing the doublewrite pages read from the file

Returns: DB_SUCCESS or error code

◆ operator=() [1/2]

Double_write & Double_write::operator= ( const Double_write & )

delete

◆ operator=() [2/2]

Double_write & Double_write::operator= ( Double_write && )

delete

◆ prepare()

void Double_write::prepare	(	const buf_page_t *	bpage,
		byte **	ptr,
		uint32_t *	len
	)

staticnoexcept

Extract the data and length to write to the doublewrite file.

Parameters

[in]	bpage	Page to write
[out]	ptr	Start of buffer to write
[out]	len	Length of the data to write

◆ reduced_reset_file()

void Double_write::reduced_reset_file	(	dblwr::File &	file,
		uint32_t	pages_per_file,
		uint32_t	phy_size
	)

staticnoexcept

Reset the size in bytes to the configured size.

Parameters

[in,out]	file	File to reset
[in]	pages_per_file	Number of pages to be created in doublewrite file
[in]	phy_size	physical page size

◆ reset_file()

void Double_write::reset_file	(	dblwr::File &	file,
		bool	truncate
	)

staticnoexcept

Reset the size in bytes to the configured size.

Parameters

[in,out]	file	File to reset.
[in]	truncate	Truncate the file to configured size if true.

◆ reset_files()

static void Double_write::reset_files ( )

inlinestaticnoexcept

Reset the size in bytes to the configured size of all files.

◆ shutdown()

void Double_write::shutdown ( )

staticnoexcept

Free the data structures.

◆ single_write()

void Double_write::single_write	(	Segment *	segment,
		const buf_page_t *	bpage,
		file::Block *	e_block
	)

staticnoexcept

Write the data to disk synchronously.

Parameters

[in]	segment	Segment to write to.
[in]	bpage	Page to write.
[in]	e_block	Encrypted block. Can be nullptr.

◆ start()

static dberr_t Double_write::start ( )

staticprivatenoexcept

Create the singleton instance, start the flush thread.

Returns: DB_SUCCESS or error code

◆ submit()

static void Double_write::submit	(	buf_flush_t	flush_type,
		buf_page_t *	bpage,
		const file::Block *	e_block
	)

inlinestaticnoexcept

Get the instance that handles a particular page's IO.

Submit the write request to the a double write queue that is empty.

Parameters

[in]	flush_type	Flush type.
[in]	bpage	Page from the buffer pool.
[in]	e_block	compressed + encrypted frame contents or nullptr.

◆ sync_page_flush()

dberr_t Double_write::sync_page_flush	(	buf_page_t *	bpage,
		file::Block *	e_block
	)

staticnoexcept

Writes a single page to the doublewrite buffer on disk, syncs it, then writes the page to the datafile.

The page will be evicted from the Buffer Pool.

Parameters

[in]	bpage	Data page to write to disk.
[in]	e_block	Encrypted data block.

Returns: DB_SUCCESS or error code

◆ toggle()

static void Double_write::toggle ( ulong value )

inlinestaticnoexcept

Toggle the doublewrite buffer dynamically.

Parameters

[in] value Current value

◆ wait_for_pending_batch()

bool Double_write::wait_for_pending_batch ( )

inlinenoexcept

Wait for any pending batch to complete.

Returns: true if the thread had to wait for another batch.

◆ write()

void Double_write::write ( buf_flush_t flush_type )

noexcept

Process the requests in the flush queue, write the blocks to the double write file, sync the file if required and then write to the data files.

◆ write_complete()

void Double_write::write_complete	(	buf_page_t *	bpage,
		buf_flush_t	flush_type
	)

staticnoexcept

Updates the double write buffer when a write request is completed.

Parameters

[in,out]	bpage	Block that has just been written to disk.
[in]	flush_type	Flush type that triggered the write.

◆ write_data_pages()

void Double_write::write_data_pages	(	buf_flush_t	flush_type,
		uint16_t	batch_id
	)

noexcept

◆ write_dblwr_pages()

uint16_t Double_write::write_dblwr_pages ( buf_flush_t flush_type )

virtualnoexcept

Reimplemented in Reduced_double_write.

◆ write_pages()

void Double_write::write_pages ( buf_flush_t flush_type )

noexcept

Process the requests in the flush queue, write the blocks to the double write file, sync the file if required and then issue asynchronous writes to the data files.

The pages are not evicted from the Buffer Pool on successful write.

Parameters

[in] flush_type LRU or FLUSH request.

◆ write_to_datafile()

dberr_t Double_write::write_to_datafile	(	const buf_page_t *	in_bpage,
		bool	sync,
		const file::Block *	e_block,
		std::function< void(dberr_t err)>	pre_io_complete_callback
	)

staticnoexcept

Writes a page that has already been written to the doublewrite buffer to the data file.

It is the job of the caller to sync the datafile. If the sync is true, the page will be evicted from the LRU.

Parameters

[in]	in_bpage	Page to write.
[in]	sync	true if it's a synchronous write.
[in]	e_block	block containing encrypted data frame.
[in]	pre_io_complete_callback	A callback to be called after the IO completes, but before the `buf_page_io_complete()` is called.

Returns: DB_SUCCESS or error code

The global Reduced Doublewrite instances.

◆ s_r_LRU_batch_segments

Double_write::Batch_segments * Double_write::s_r_LRU_batch_segments {}

staticprotected

File segments to use for LRU batched writes in reduced dblwr mode.

◆ s_regular_last_batch_id

uint32_t Double_write::s_regular_last_batch_id {}

staticprotected

Last used batch_id for regular batch segments.

Any id greater than this belongs to reduced double write

◆ s_segments

std::vector< Batch_segment * > Double_write::s_segments {}

staticprotected

For indexing batch segments by ID.

◆ s_single_segments

Double_write::Segments * Double_write::s_single_segments {}

staticprotected

File segments to use for single page writes.

The documentation for this class was generated from the following file:

storage/innobase/buf/buf0dblwr.cc

Classes

Public Member Functions

Static Public Member Functions

Public Attributes

Static Public Attributes

Protected Types

Static Protected Member Functions

Protected Attributes

Static Protected Attributes

Static Private Member Functions

Detailed Description

Member Typedef Documentation

◆ Batch_segments

◆ Instances

◆ Segments

Constructor & Destructor Documentation

◆ Double_write() [1/3]

◆ ~Double_write()

◆ Double_write() [2/3]

◆ Double_write() [3/3]

Member Function Documentation

◆ batch_completed()

◆ batch_started()

◆ check_block()

◆ check_page_lsn()

◆ create_batch_segments()

◆ create_reduced()

◆ create_reduced_batch_segments()

◆ create_single_segments()

◆ create_v1()

◆ create_v2()

◆ croak()

◆ enqueue()

◆ flush_to_disk()

◆ force_flush() [1/2]

◆ force_flush() [2/2]

◆ free_segments()

◆ get()

◆ id()

◆ init_file()

◆ init_v1()

◆ instance() [1/2]

◆ instance() [2/2]

◆ is_fsync_required()

◆ is_reduced_batch_id()

◆ load()

◆ load_reduced_batch()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ prepare()

◆ reduced_reset_file()

◆ reset_file()

◆ reset_files()

◆ shutdown()

◆ single_write()

◆ start()

◆ submit()

◆ sync_page_flush()

◆ toggle()

◆ wait_for_pending_batch()

◆ write()

◆ write_complete()

◆ write_data_pages()

◆ write_dblwr_pages()

◆ write_pages()

◆ write_to_datafile()

Member Data Documentation

◆ m_batch_running

◆ m_buf_pages

◆ m_buffer

◆ m_bytes_written

◆ m_event

◆ m_id

◆ m_mutex

◆ s_files

◆ s_flush_list_batch_segments

◆ s_instances

◆ s_LRU_batch_segments

◆ s_n_instances

◆ s_r_files