Segment for batched writes. More...

Inheritance diagram for Batch_segment:

Public Member Functions
	Batch_segment (uint16_t id, dblwr::File &file, page_no_t start, uint32_t n_pages)
	Constructor. More...

	Batch_segment (uint16_t id, dblwr::File &file, uint32_t phy_size, page_no_t start, uint32_t n_pages)
	Constructor. More...

	~Batch_segment () noexcept override
	Destructor. More...

uint16_t	id () const noexcept

void	write (const Buffer &buffer) noexcept
	Write a batch to the segment. More...

void	write (const byte *buf, uint32_t len) noexcept
	Write a batch to the segment. More...

bool	write_complete () noexcept
	Called on page write completion. More...

void	reset () noexcept
	Reset the state. More...

void	set_batch_size (uint32_t size) noexcept
	Set the batch size. More...

uint32_t	batch_size () const noexcept

void	start (Double_write *dblwr) noexcept
	Note that the batch has started for the double write instance. More...

void	completed () noexcept
	Note that the batch has completed. More...

Public Member Functions inherited from Segment
	Segment (dblwr::File &file, page_no_t start, uint32_t n_pages)
	Constructor. More...

	Segment (dblwr::File &file, uint32_t phy_size, page_no_t start, uint32_t n_pages)
	Constructor. More...

virtual	~Segment ()=default
	Destructor. More...

void	write (const void *ptr, uint32_t len) noexcept
	Write to the segment. More...

void	flush () noexcept
	Flush the segment to disk. More...

	Segment (Segment &&)=delete

	Segment (const Segment &)=delete

Segment &	operator= (Segment &&)=delete

Segment &	operator= (const Segment &)=delete

Public Attributes
uint16_t	m_id {}
	Batch segment ID. More...

Double_write *	m_dblwr {}
	The instance that is being written to disk. More...

byte	m_pad1 [ut::INNODB_CACHE_LINE_SIZE]

uint32_t	m_batch_size {}
	Size of the batch. More...

byte	m_pad2 [ut::INNODB_CACHE_LINE_SIZE]

std::atomic_int	m_uncompleted {}
	Number of page writes in the batch which are still not completed. More...

Public Attributes inherited from Segment
dblwr::File &	m_file
	File that owns the segment. More...

uint32_t	m_phy_size {}
	Physical page size of each entry/Segment. More...

os_offset_t	m_start {}
	Physical offset in the file for the segment. More...

os_offset_t	m_end {}
	Physical offset up to which this segment is responsible for. More...

Detailed Description

Segment for batched writes.

Constructor & Destructor Documentation

◆ Batch_segment() [1/2]

Batch_segment::Batch_segment	(	uint16_t	id,
		dblwr::File &	file,
		page_no_t	start,
		uint32_t	n_pages
	)

inline

Constructor.

Parameters

[in]	id	Segment ID.
[in]	file	File that owns the segment.
[in]	start	Offset (page number) of segment in the file.
[in]	n_pages	Number of pages in the segment.

◆ Batch_segment() [2/2]

Batch_segment::Batch_segment	(	uint16_t	id,
		dblwr::File &	file,
		uint32_t	phy_size,
		page_no_t	start,
		uint32_t	n_pages
	)

inline

Constructor.

Parameters

[in]	id	Segment ID.
[in]	file	File that owns the segment.
[in]	phy_size	physical size of each segment entry
[in]	start	Offset (page number) of segment in the file.
[in]	n_pages	Number of pages in the segment.

◆ ~Batch_segment()

Batch_segment::~Batch_segment ( )

inlineoverridenoexcept

Destructor.

Member Function Documentation

◆ batch_size()

uint32_t Batch_segment::batch_size ( ) const

inlinenoexcept

Returns: the batch size.

◆ completed()

void Batch_segment::completed ( )

inlinenoexcept

Note that the batch has completed.

◆ id()

uint16_t Batch_segment::id ( ) const

inlinenoexcept

Returns: the batch segment ID.

◆ reset()

void Batch_segment::reset ( void )

inlinenoexcept

Reset the state.

◆ set_batch_size()

void Batch_segment::set_batch_size ( uint32_t size )

inlinenoexcept

Set the batch size.

Parameters

[in] size Number of pages to write to disk.

◆ start()

void Batch_segment::start ( Double_write * dblwr )

inlinenoexcept

Note that the batch has started for the double write instance.

Parameters

[in] dblwr Instance for which batch has started.

◆ write() [1/2]

void Batch_segment::write ( const Buffer & buffer )

noexcept

Write a batch to the segment.

Parameters

[in] buffer Buffer to write.

◆ write() [2/2]

void Batch_segment::write	(	const byte *	buf,
		uint32_t	len
	)

noexcept

Write a batch to the segment.

Parameters

[in]	buf	Buffer to write
[in]	len	amount of data to write

◆ write_complete()

bool Batch_segment::write_complete ( )

inlinenoexcept

Called on page write completion.

Returns: if batch ended.

Member Data Documentation

◆ m_batch_size

uint32_t Batch_segment::m_batch_size {}

Size of the batch.

Set to number of pages to be written with set_batch_size() before scheduling writes to data pages. Reset to zero with reset() after all IOs are completed. Read only by the thread which has observed the last IO completion, the one which will reset it back to zero and enqueue the segment for future reuse. Accesses to this field are ordered by happens-before relation: set_batch_size() sequenced-before fil_io() happens-before dblwr::write_complete() entry sequenced-before batch_size() sequenced-before reset() sequenced-before enqueue() synchronizes-with dequeue() sequenced-before set_batch_size() ...

◆ m_dblwr

Double_write* Batch_segment::m_dblwr {}

The instance that is being written to disk.

◆ m_id

uint16_t Batch_segment::m_id {}

Batch segment ID.

◆ m_pad1

byte Batch_segment::m_pad1[ut::INNODB_CACHE_LINE_SIZE]

◆ m_pad2

byte Batch_segment::m_pad2[ut::INNODB_CACHE_LINE_SIZE]

◆ m_uncompleted

std::atomic_int Batch_segment::m_uncompleted {}

Number of page writes in the batch which are still not completed.

Set to equal m_batch_size by set_batch_size(), and decremented when a page write is finished (either by failing/not attempting or in IO completion). It serves a role of a reference counter: when it drops to zero, the segment can be enqueued back to the pool of available segments. Accessing a segment which has m_uncompleted == 0 is safe only from the thread which knows it can not be recycled - for example because it's the thread which has caused the m_uncompleted drop to 0 and will enqueue it, or it's the thread which has just dequeued it, or it is handling shutdown.

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

storage/innobase/buf/buf0dblwr.cc

Public Member Functions

Public Attributes

Detailed Description

Constructor & Destructor Documentation

◆ Batch_segment() [1/2]

◆ Batch_segment() [2/2]

◆ ~Batch_segment()

Member Function Documentation

◆ batch_size()

◆ completed()

◆ id()

◆ reset()

◆ set_batch_size()

◆ start()

◆ write() [1/2]

◆ write() [2/2]

◆ write_complete()

Member Data Documentation

◆ m_batch_size

◆ m_dblwr

◆ m_id

◆ m_pad1

◆ m_pad2

◆ m_uncompleted