#include <buf0buf.h>

Public Member Functions
	buf_page_t (const buf_page_t &other)
	Copy constructor. More...

void	set_dblwr_batch_id (uint16_t batch_id)
	Set the doublewrite buffer ID. More...

uint16_t	get_dblwr_batch_id () const

space_id_t	space () const noexcept
	Retrieve the tablespace id. More...

page_no_t	page_no () const noexcept
	Retrieve the page number. More...

bool	is_stale () const
	Checks if this space reference saved during last page ID initialization was deleted or truncated since. More...

bool	was_stale () const
	Checks if this space reference saved during last page ID initialization was deleted or truncated since. More...

fil_space_t *	get_space () const
	Retrieve the tablespace object if one was available during page ID initialization. More...

void	reset_page_id (page_id_t new_page_id)
	Sets stored page ID to the new value. More...

void	reset_page_id ()
	Sets stored value to invalid/empty value. More...

FlushObserver *	get_flush_observer () noexcept

void	set_flush_observer (FlushObserver *flush_observer) noexcept
	Set the flush observer for the page. More...

void	reset_flush_observer () noexcept
	Remove the flush observer. More...

lsn_t	get_newest_lsn () const noexcept

lsn_t	get_oldest_lsn () const noexcept

bool	is_dirty () const noexcept

void	set_newest_lsn (lsn_t lsn) noexcept
	Set the latest modification LSN. More...

void	set_oldest_lsn (lsn_t lsn) noexcept
	Set the LSN when the page is modified for the first time. More...

void	set_clean () noexcept
	Set page to clean state. More...

Public Attributes
buf_page_t *	hash
	Node used in chaining to buf_pool->page_hash or buf_pool->zip_hash. More...

uint32_t	access_time
	Time of first access, or 0 if the block was never accessed in the buffer pool. More...

uint32_t	m_version {}
	Version of fil_space_t when the page was updated. More...

uint16_t	m_dblwr_id {}
	Double write instance ordinal value during writes. More...

bool	old
	true if the block is in the old blocks in buf_pool->LRU_old More...

bool	file_page_was_freed
	This is set to TRUE when fsp frees a page in buffer pool; protected by buf_pool->zip_mutex or buf_block_t::mutex. More...

bool	in_flush_list
	TRUE if in buf_pool->flush_list; when buf_pool->flush_list_mutex is free, the following should hold: in_flush_list == (state == BUF_BLOCK_FILE_PAGE \|\| state == BUF_BLOCK_ZIP_DIRTY) Writes to this field must be covered by both buf_pool->flush_list_mutex and block->mutex. More...

bool	in_free_list
	true if in buf_pool->free; when buf_pool->free_list_mutex is free, the following should hold: in_free_list == (state == BUF_BLOCK_NOT_USED) More...

bool	in_LRU_list
	true if the page is in the LRU list; used in debugging More...

bool	in_page_hash
	true if in buf_pool->page_hash More...

bool	in_zip_hash
	true if in buf_pool->zip_hash More...

General fields
None of these bit-fields must be modified without holding buf_page_get_mutex() [buf_block_t::mutex or buf_pool->zip_mutex], since they can be stored in the same machine word.
page_id_t	id
	Page id. More...

page_size_t	size
	Page size. More...

buf_fix_count_atomic_t	buf_fix_count
	Count of how many fold this block is currently bufferfixed. More...

buf_io_fix	io_fix
	Type of pending I/O operation. More...

buf_page_state	state
	Block state. More...

buf_flush_t	flush_type
	If this block is currently being flushed to disk, this tells the flush_type. More...

uint8_t	buf_pool_index
	Index number of the buffer pool that this block belongs to. More...

Private Member Functions
void	space_id_changed ()
	Updates new space reference and acquires "reference count latch" and the current version of the space object. More...

Page flushing fields
All these are protected by buf_pool->mutex.
lsn_t	newest_modification
	The flush LSN, LSN when this page was written to the redo log. More...

lsn_t	oldest_modification
	log sequence number of the youngest modification to this block, zero if not modified. More...

	UT_LIST_NODE_T (buf_page_t) list
	Based on state, this is a list node, protected by the corresponding list mutex, in one of the following lists in buf_pool: More...

LRU replacement algorithm fields
log sequence number of the START of the log entry written of the oldest modification to this block which has not yet been flushed on disk; zero if all modifications are on disk. Writes to this field must be covered by both block->mutex and buf_pool->flush_list_mutex. Hence reads can happen while holding any one of the two mutexes These fields are protected by both buf_pool->LRU_list_mutex and the block mutex.
page_zip_des_t	zip
	compressed page; zip.data (but not the data it points to) is protected by buf_pool->zip_mutex; state == BUF_BLOCK_ZIP_PAGE and zip.data == NULL means an active buf_pool->watch More...

FlushObserver *	m_flush_observer {}
	Flush observer instance. More...

fil_space_t *	m_space {}
	Tablespace instance that this page belongs to. More...

uint32_t	freed_page_clock
	The value of buf_pool->freed_page_clock when this block was the last time put to the head of the LRU list; a thread is allowed to read this for heuristic purposes without holding any mutex or latch. More...

	UT_LIST_NODE_T (buf_page_t) LRU
	node of the LRU list More...

Constructor & Destructor Documentation

◆ buf_page_t()

buf_page_t::buf_page_t ( const buf_page_t & other )

inline

Copy constructor.

Parameters

[in] other Instance to copy from.

Member Function Documentation

◆ get_dblwr_batch_id()

uint16_t buf_page_t::get_dblwr_batch_id ( ) const

inline

Returns: the double write batch id, or uint16_t max if undefined.

◆ get_flush_observer()

FlushObserver* buf_page_t::get_flush_observer ( )

inlinenoexcept

Returns: the flush observer instance.

◆ get_newest_lsn()

lsn_t buf_page_t::get_newest_lsn ( ) const

inlinenoexcept

Returns: the LSN of the latest modification.

◆ get_oldest_lsn()

lsn_t buf_page_t::get_oldest_lsn ( ) const

inlinenoexcept

Returns: the LSN of the first modification since the last time it was clean.

◆ get_space()

fil_space_t* buf_page_t::get_space ( ) const

inline

Retrieve the tablespace object if one was available during page ID initialization.

The returned object is safe to use as long as this buf_page_t object is not changed. Caller should have a IO fix, buffer fix, mutex or any other mean to assure the page will not be freed. After that is released the space object may be freed.

Returns: tablespace object

◆ is_dirty()

bool buf_page_t::is_dirty ( ) const

inlinenoexcept

Returns: true if the page is dirty.

◆ is_stale()

bool buf_page_t::is_stale ( ) const

inline

Checks if this space reference saved during last page ID initialization was deleted or truncated since.

Returns: true when space reference stored leads was deleted or truncated and this page should be discarded. Result is up to date until the fil_shard mutex is released.

◆ page_no()

page_no_t buf_page_t::page_no ( ) const

inlinenoexcept

Retrieve the page number.

Returns: page number

◆ reset_flush_observer()

void buf_page_t::reset_flush_observer ( )

inlinenoexcept

Remove the flush observer.

◆ reset_page_id() [1/2]

void buf_page_t::reset_page_id ( )

inline

Sets stored value to invalid/empty value.

Handles space object reference count.

◆ reset_page_id() [2/2]

void buf_page_t::reset_page_id ( page_id_t new_page_id )

inline

Sets stored page ID to the new value.

Handles space object reference count.

Parameters

[in] new_page_id new page ID to be set.

◆ set_clean()

void buf_page_t::set_clean ( )

inlinenoexcept

Set page to clean state.

◆ set_dblwr_batch_id()

void buf_page_t::set_dblwr_batch_id ( uint16_t batch_id )

inline

Set the doublewrite buffer ID.

Parameters

[in] batch_id Double write batch ID that flushed the page.

◆ set_flush_observer()

void buf_page_t::set_flush_observer ( FlushObserver * flush_observer )

inlinenoexcept

Set the flush observer for the page.

Parameters

[in] flush_observer The flush observer to set.

◆ set_newest_lsn()

void buf_page_t::set_newest_lsn ( lsn_t lsn )

inlinenoexcept

Set the latest modification LSN.

Parameters

[in] lsn Latest modification lSN.

◆ set_oldest_lsn()

void buf_page_t::set_oldest_lsn ( lsn_t lsn )

noexcept

Set the LSN when the page is modified for the first time.

Parameters

[in] lsn First modification LSN.

◆ space()

space_id_t buf_page_t::space ( ) const

inlinenoexcept

Retrieve the tablespace id.

Returns: tablespace id

◆ space_id_changed()

void buf_page_t::space_id_changed ( )

inlineprivate

Updates new space reference and acquires "reference count latch" and the current version of the space object.

◆ UT_LIST_NODE_T() [1/2]

buf_page_t::UT_LIST_NODE_T ( buf_page_t )

Based on state, this is a list node, protected by the corresponding list mutex, in one of the following lists in buf_pool:

BUF_BLOCK_NOT_USED: free, withdraw
BUF_BLOCK_FILE_PAGE: flush_list
BUF_BLOCK_ZIP_DIRTY: flush_list
BUF_BLOCK_ZIP_PAGE: zip_clean

The node pointers are protected by the corresponding list mutex.

The contents of the list node is undefined if !in_flush_list && state == BUF_BLOCK_FILE_PAGE, or if state is one of BUF_BLOCK_MEMORY, BUF_BLOCK_REMOVE_HASH or BUF_BLOCK_READY_IN_USE.

◆ UT_LIST_NODE_T() [2/2]

buf_page_t::UT_LIST_NODE_T ( buf_page_t )

node of the LRU list

◆ was_stale()

bool buf_page_t::was_stale ( ) const

inline

Checks if this space reference saved during last page ID initialization was deleted or truncated since.

Returns: true when space reference stored leads was deleted or truncated and this page should be discarded. When false is returned, the status of stale is checked to be guaranteed.

Member Data Documentation

◆ access_time

uint32_t buf_page_t::access_time

Time of first access, or 0 if the block was never accessed in the buffer pool.

Protected by block mutex

◆ buf_fix_count

buf_fix_count_atomic_t buf_page_t::buf_fix_count

Count of how many fold this block is currently bufferfixed.

◆ buf_pool_index

uint8_t buf_page_t::buf_pool_index

Index number of the buffer pool that this block belongs to.

◆ file_page_was_freed

bool buf_page_t::file_page_was_freed

This is set to TRUE when fsp frees a page in buffer pool; protected by buf_pool->zip_mutex or buf_block_t::mutex.

◆ flush_type

buf_flush_t buf_page_t::flush_type

If this block is currently being flushed to disk, this tells the flush_type.

See also: buf_flush_t

◆ freed_page_clock

uint32_t buf_page_t::freed_page_clock

The value of buf_pool->freed_page_clock when this block was the last time put to the head of the LRU list; a thread is allowed to read this for heuristic purposes without holding any mutex or latch.

◆ hash

buf_page_t* buf_page_t::hash

Node used in chaining to buf_pool->page_hash or buf_pool->zip_hash.

◆ id

page_id_t buf_page_t::id

Page id.

◆ in_flush_list

bool buf_page_t::in_flush_list

TRUE if in buf_pool->flush_list; when buf_pool->flush_list_mutex is free, the following should hold: in_flush_list == (state == BUF_BLOCK_FILE_PAGE || state == BUF_BLOCK_ZIP_DIRTY) Writes to this field must be covered by both buf_pool->flush_list_mutex and block->mutex.

Hence reads can happen while holding any one of the two mutexes

◆ in_free_list

bool buf_page_t::in_free_list

true if in buf_pool->free; when buf_pool->free_list_mutex is free, the following should hold: in_free_list == (state == BUF_BLOCK_NOT_USED)

◆ in_LRU_list

bool buf_page_t::in_LRU_list

true if the page is in the LRU list; used in debugging

◆ in_page_hash

bool buf_page_t::in_page_hash

true if in buf_pool->page_hash

◆ in_zip_hash

bool buf_page_t::in_zip_hash

true if in buf_pool->zip_hash

◆ io_fix

buf_io_fix buf_page_t::io_fix

Type of pending I/O operation.

◆ m_dblwr_id

uint16_t buf_page_t::m_dblwr_id {}

Double write instance ordinal value during writes.

This is used by IO completion (writes) to select the double write instance.

◆ m_flush_observer

FlushObserver* buf_page_t::m_flush_observer {}

Flush observer instance.

◆ m_space

fil_space_t* buf_page_t::m_space {}

Tablespace instance that this page belongs to.

◆ m_version

uint32_t buf_page_t::m_version {}

Version of fil_space_t when the page was updated.

It can also be viewed as the truncation number.

◆ newest_modification

lsn_t buf_page_t::newest_modification

private

The flush LSN, LSN when this page was written to the redo log.

For non redo logged pages this is set using: buf_flush_borrow_lsn()

◆ old

bool buf_page_t::old

true if the block is in the old blocks in buf_pool->LRU_old

◆ oldest_modification

lsn_t buf_page_t::oldest_modification

private

log sequence number of the youngest modification to this block, zero if not modified.

Protected by block mutex

◆ size

page_size_t buf_page_t::size

Page size.

◆ state

buf_page_state buf_page_t::state

Block state.

See also: buf_page_in_file

◆ zip

page_zip_des_t buf_page_t::zip

compressed page; zip.data (but not the data it points to) is protected by buf_pool->zip_mutex; state == BUF_BLOCK_ZIP_PAGE and zip.data == NULL means an active buf_pool->watch

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

storage/innobase/include/buf0buf.h

Public Member Functions

Public Attributes

Private Member Functions

Page flushing fields

LRU replacement algorithm fields

Constructor & Destructor Documentation

◆ buf_page_t()

Member Function Documentation

◆ get_dblwr_batch_id()

◆ get_flush_observer()

◆ get_newest_lsn()

◆ get_oldest_lsn()

◆ get_space()

◆ is_dirty()

◆ is_stale()

◆ page_no()

◆ reset_flush_observer()

◆ reset_page_id() [1/2]

◆ reset_page_id() [2/2]

◆ set_clean()

◆ set_dblwr_batch_id()

◆ set_flush_observer()

◆ set_newest_lsn()

◆ set_oldest_lsn()

◆ space()

◆ space_id_changed()

◆ UT_LIST_NODE_T() [1/2]

◆ UT_LIST_NODE_T() [2/2]

◆ was_stale()

Member Data Documentation

◆ access_time

◆ buf_fix_count

◆ buf_pool_index

◆ file_page_was_freed

◆ flush_type

◆ freed_page_clock

◆ hash

◆ id

◆ in_flush_list

◆ in_free_list

◆ in_LRU_list

◆ in_page_hash

◆ in_zip_hash

◆ io_fix

◆ m_dblwr_id

◆ m_flush_observer

◆ m_space

◆ m_version

◆ newest_modification

◆ old

◆ oldest_modification

◆ size

◆ state

◆ zip