Transaction system. More...

#include "univ.i"
#include "buf0buf.h"
#include "fil0fil.h"
#include "trx0types.h"
#include "mem0mem.h"
#include "mtr0mtr.h"
#include "page0types.h"
#include "ut0byte.h"
#include "ut0class_life_cycle.h"
#include "ut0guarded.h"
#include "ut0lst.h"
#include "ut0mutex.h"
#include <atomic>
#include <unordered_map>
#include <vector>
#include "trx0trx.h"
#include "trx0sys.ic"

Classes
class	Space_Ids
	List of undo tablespace IDs. More...

class	Trx_by_id_with_min

struct	Trx_by_id_with_min::Trx_track_hash

struct	Trx_shard
	Shard for subset of transactions. More...

struct	trx_sys_t
	The transaction system central memory data structure. More...

Macros
#define	TRX_SYS_MYSQL_LOG_INFO (UNIV_PAGE_SIZE - 1000)
	The offset of the MySQL binlog offset info in the trx system header. More...

#define	TRX_SYS_TRX_NUM_GTID (TRX_SYS_MYSQL_LOG_INFO + TRX_SYS_MYSQL_LOG_NAME + TRX_SYS_MYSQL_LOG_NAME_LEN)
	Reserve next 8 bytes for transaction number up to which GTIDs are persisted to table. More...

#define	TRX_SYS_TRX_NUM_END (TRX_SYS_TRX_NUM_GTID + 8)

Functions
static bool	trx_sys_hdr_page (const page_id_t &page_id)
	Checks if a page address is the trx sys header page. More...

purge_pq_t *	trx_sys_init_at_db_start (void)
	Creates and initializes the central memory structures for the transaction system. More...

void	trx_sys_create (void)
	Creates the trx_sys instance and initializes purge_queue and mutex. More...

void	trx_sys_create_sys_pages (void)
	Creates and initializes the transaction system at the database creation. More...

page_no_t	trx_sysf_rseg_find_page_no (ulint rseg_id)
	Find the page number in the TRX_SYS page for a given slot/rseg_id. More...

ulint	trx_sysf_rseg_find_free (mtr_t *mtr)
	Look for a free slot for a rollback segment in the trx system file copy. More...

static trx_sysf_t *	trx_sysf_get (mtr_t *mtr)
	Gets a pointer to the transaction system file copy and x-locks its page. More...

static space_id_t	trx_sysf_rseg_get_space (trx_sysf_t sys_header, ulint i, mtr_t mtr)
	Gets the space of the nth rollback segment slot in the trx system file copy. More...

static page_no_t	trx_sysf_rseg_get_page_no (trx_sysf_t sys_header, ulint i, mtr_t mtr)
	Gets the page number of the nth rollback segment slot in the trx system file copy. More...

static void	trx_sysf_rseg_set_space (trx_sysf_t sys_header, ulint i, space_id_t space, mtr_t mtr)
	Sets the space id of the nth rollback segment slot in the trx system file copy. More...

static void	trx_sysf_rseg_set_page_no (trx_sysf_t sys_header, ulint i, page_no_t page_no, mtr_t mtr)
	Set the page number of the nth rollback segment slot in the trx system file copy. More...

trx_id_t	trx_sys_allocate_trx_id ()
	Allocates a new transaction id (for trx->id). More...

trx_id_t	trx_sys_allocate_trx_no ()
	Allocates a new transaction number (for trx->no). More...

trx_id_t	trx_sys_get_next_trx_id_or_no ()
	Retrieves a next value that will be allocated if trx_sys_allocate_trx_id() or trx_sys_allocate_trx_id_trx_no() was called. More...

static void	trx_write_trx_id (byte *ptr, trx_id_t id)
	Writes a trx id to an index page. More...

static trx_id_t	trx_read_trx_id (const byte *ptr)
	Reads a trx id from an index page. More...

static trx_t *	trx_rw_is_active (trx_id_t trx_id, bool do_ref_count)
	Checks if a rw transaction with the given id is active. More...

void	trx_sys_persist_gtid_num (trx_id_t gtid_trx_no)
	Persist transaction number limit below which all transaction GTIDs are persisted to disk table. More...

trx_id_t	trx_sys_oldest_trx_no ()

void	trx_sys_get_binlog_prepared (std::vector< trx_id_t > &trx_ids)
	Get a list of all binlog prepared transactions. More...

void	trx_sys_read_binlog_position (char *file, uint64_t &offset)
	Get current binary log positions stored. More...

bool	trx_sys_write_binlog_position (const char last_file, uint64_t last_offset, const char file, uint64_t offset)
	Update binary log position if not already updated. More...

void	trx_sys_update_mysql_binlog_offset (trx_t trx, mtr_t mtr)
	Updates the offset information about the end of the MySQL binlog entry which corresponds to the transaction being committed, external XA transaction being prepared or rolled back. More...

void	trx_sys_close (void)
	Shutdown/Close the transaction system. More...

static bool	trx_sys_need_rollback ()
	Determine if there are incomplete transactions in the system. More...

size_t	trx_sys_recovered_active_trxs_count ()
	Reads number of recovered transactions which have state equal to TRX_STATE_ACTIVE (so are not prepared transactions). More...

void	trx_sys_before_pre_dd_shutdown_validate ()
	Validates lists of transactions at the very beginning of the pre-dd-shutdown phase. More...

void	trx_sys_after_pre_dd_shutdown_validate ()
	Validates lists of transactions at the very end of the pre-dd-shutdown phase. More...

void	trx_sys_after_background_threads_shutdown_validate ()
	Validates lists of transactions after all background threads of InnoDB exited during shutdown of MySQL. More...

static void	trx_sys_rw_trx_add (trx_t *trx)
	Add the transaction to the RW transaction set. More...

bool	trx_sys_validate_trx_list ()
	Validate the trx_sys_t::rw_trx_list. More...

void	trx_sys_undo_spaces_init ()
	Initialize trx_sys_undo_spaces, called once during srv_start(). More...

void	trx_sys_undo_spaces_deinit ()
	Free the resources occupied by trx_sys_undo_spaces, called once during thread de-initialization. More...

size_t	trx_get_shard_no (trx_id_t trx_id)
	Computes shard number for a given trx_id. More...

static void	trx_sys_mutex_enter ()
	Acquire the trx_sys->mutex. More...

static void	trx_sys_mutex_exit ()
	Release the trx_sys->mutex. More...

static bool	trx_sys_mutex_own ()
	Test if trx_sys->mutex is owned. More...

static bool	trx_sys_serialisation_mutex_own ()
	Test if trx_sys->serialisation_mutex is owned. More...

static void	trx_sys_serialisation_mutex_enter ()
	Acquire the trx_sys->serialisation_mutex. More...

static void	trx_sys_serialisation_mutex_exit ()
	Release the trx_sys->serialisation_mutex. More...

Variables
trx_sys_t *	trx_sys
	The transaction system. More...

uint	trx_rseg_n_slots_debug

constexpr uint32_t	TRX_SYS_SYSTEM_RSEG_ID = 0
	The automatically created system rollback segment has this id. More...

constexpr uint32_t	TRX_SYS = FSEG_PAGE_DATA
	The offset of the transaction system header on the page. More...

constexpr uint32_t	TRX_SYS_TRX_ID_STORE = 0
	Transaction system header. More...

constexpr uint32_t	TRX_SYS_FSEG_HEADER = 8
	segment header for the tablespace segment the trx system is created into More...

constexpr uint32_t	TRX_SYS_RSEGS = 8 + FSEG_HEADER_SIZE
	the start of the array of rollback segment specification slots More...

constexpr size_t	TRX_SYS_OLD_N_RSEGS = 256

constexpr size_t	TRX_SYS_OLD_TMP_RSEGS = 32

constexpr uint32_t	TRX_SYS_MYSQL_LOG_NAME_LEN = 512
	Maximum length of MySQL binlog file name, in bytes. More...

constexpr uint32_t	TRX_SYS_MYSQL_LOG_MAGIC_N = 873422344
	Contents of TRX_SYS_MYSQL_LOG_MAGIC_N_FLD. More...

constexpr uint32_t	TRX_SYS_MYSQL_LOG_MAGIC_N_FLD = 0
	magic number which is TRX_SYS_MYSQL_LOG_MAGIC_N if we have valid data in the MySQL binlog info More...

constexpr uint32_t	TRX_SYS_MYSQL_LOG_OFFSET_HIGH = 4
	high 4 bytes of the offset within that file More...

constexpr uint32_t	TRX_SYS_MYSQL_LOG_OFFSET_LOW = 8
	low 4 bytes of the offset within that file More...

constexpr uint32_t	TRX_SYS_MYSQL_LOG_NAME = 12
	MySQL log file name. More...

constexpr size_t	TRX_SHARDS_N = 256
	Number of shards created for transactions. More...

Space_Ids *	trx_sys_undo_spaces
	A list of undo tablespace IDs found in the TRX_SYS page. More...

constexpr trx_id_t	TRX_SYS_TRX_ID_WRITE_MARGIN = 256
	When a trx id which is zero modulo this number (which must be a power of two) is assigned, the field TRX_SYS_TRX_ID_STORE on the transaction system page is updated. More...

#define	TRX_SYS_DOUBLEWRITE (UNIV_PAGE_SIZE - 200)
	Doublewrite buffer. More...

#define	TRX_SYS_DOUBLEWRITE_BLOCK_SIZE FSP_EXTENT_SIZE
	Size of the doublewrite block in pages. More...

constexpr uint32_t	TRX_SYS_DOUBLEWRITE_FSEG = 0
	fseg header of the fseg containing the doublewrite buffer More...

constexpr uint32_t	TRX_SYS_DOUBLEWRITE_MAGIC = FSEG_HEADER_SIZE
	4-byte magic number which shows if we already have created the doublewrite buffer More...

constexpr uint32_t	TRX_SYS_DOUBLEWRITE_BLOCK1 = 4 + FSEG_HEADER_SIZE
	page number of the first page in the first sequence of 64 (= FSP_EXTENT_SIZE) consecutive pages in the doublewrite buffer More...

constexpr uint32_t	TRX_SYS_DOUBLEWRITE_BLOCK2 = 8 + FSEG_HEADER_SIZE
	page number of the first page in the second sequence of 64 consecutive pages in the doublewrite buffer More...

constexpr uint32_t	TRX_SYS_DOUBLEWRITE_REPEAT = 12
	we repeat TRX_SYS_DOUBLEWRITE_MAGIC, TRX_SYS_DOUBLEWRITE_BLOCK1, TRX_SYS_DOUBLEWRITE_BLOCK2 so that if the trx sys header is half-written to disk, we still may be able to recover the information More...

constexpr uint32_t	TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED = 24 + FSEG_HEADER_SIZE
	If this is not yet set to TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED_N, we must reset the doublewrite buffer, because starting from 4.1.x the space id of a data page is stored into FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID. More...

constexpr uint32_t	TRX_SYS_DOUBLEWRITE_MAGIC_N = 536853855
	Contents of TRX_SYS_DOUBLEWRITE_MAGIC. More...

constexpr uint32_t	TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED_N = 1783657386
	Contents of TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED. More...

Detailed Description

Transaction system.

Created 3/26/1996 Heikki Tuuri

Macro Definition Documentation

◆ TRX_SYS_DOUBLEWRITE

#define TRX_SYS_DOUBLEWRITE (UNIV_PAGE_SIZE - 200)

Doublewrite buffer.

The offset of the doublewrite buffer header on the trx system header page

◆ TRX_SYS_DOUBLEWRITE_BLOCK_SIZE

#define TRX_SYS_DOUBLEWRITE_BLOCK_SIZE FSP_EXTENT_SIZE

Size of the doublewrite block in pages.

◆ TRX_SYS_MYSQL_LOG_INFO

#define TRX_SYS_MYSQL_LOG_INFO (UNIV_PAGE_SIZE - 1000)

The offset of the MySQL binlog offset info in the trx system header.

◆ TRX_SYS_TRX_NUM_END

#define TRX_SYS_TRX_NUM_END (TRX_SYS_TRX_NUM_GTID + 8)

◆ TRX_SYS_TRX_NUM_GTID

#define TRX_SYS_TRX_NUM_GTID (TRX_SYS_MYSQL_LOG_INFO + TRX_SYS_MYSQL_LOG_NAME + TRX_SYS_MYSQL_LOG_NAME_LEN)

Reserve next 8 bytes for transaction number up to which GTIDs are persisted to table.

Function Documentation

◆ trx_get_shard_no()

size_t trx_get_shard_no ( trx_id_t trx_id )

inline

Computes shard number for a given trx_id.

Parameters

[in] trx_id trx_id for which shard_no should be computed

Returns: the computed shard number (number in range 0..TRX_SHARDS_N-1)

◆ trx_read_trx_id()

static trx_id_t trx_read_trx_id ( const byte * ptr )

inlinestatic

Reads a trx id from an index page.

In case that the id size changes in some future version, this function should be used instead of mach_read_...

Returns: id in: pointer to memory from where to read

◆ trx_rw_is_active()

static trx_t * trx_rw_is_active	(	trx_id_t	trx_id,
		bool	do_ref_count
	)

inlinestatic

Checks if a rw transaction with the given id is active.

Please note, that positive result means only that the trx was active at some moment during the call, but it might have already become TRX_STATE_COMMITTED_IN_MEMORY before the call returns to the caller, as this transition is protected by trx->mutex and Trx_shard's mutex, but it is impossible for the caller to hold any of these mutexes when calling this function as the function itself internally acquires Trx_shard's mutex which would cause recurrent mutex acquisition if caller already had the same mutex, or latching order violation in case of holding trx->mutex.

Parameters

[in]	trx_id	trx id of the transaction
[in]	do_ref_count	if true then increment the trx_t::n_ref_count

Returns: transaction instance if active, or NULL;

◆ trx_sys_after_background_threads_shutdown_validate()

void trx_sys_after_background_threads_shutdown_validate ( )

Validates lists of transactions after all background threads of InnoDB exited during shutdown of MySQL.

◆ trx_sys_after_pre_dd_shutdown_validate()

void trx_sys_after_pre_dd_shutdown_validate ( )

Validates lists of transactions at the very end of the pre-dd-shutdown phase.

At this point we check the mysql_trx_list again, now we don't expect purge thread transactions in the list

◆ trx_sys_allocate_trx_id()

trx_id_t trx_sys_allocate_trx_id ( )

inline

Allocates a new transaction id (for trx->id).

Before calling, the trx_sys_mutex must be acquired.

Returns: new, allocated trx id

◆ trx_sys_allocate_trx_no()

trx_id_t trx_sys_allocate_trx_no ( )

inline

Allocates a new transaction number (for trx->no).

Before calling, the trx_sys_serialisation_mutex must be acquired.

Returns: new, allocated trx no

◆ trx_sys_before_pre_dd_shutdown_validate()

void trx_sys_before_pre_dd_shutdown_validate ( )

Validates lists of transactions at the very beginning of the pre-dd-shutdown phase.

All connections are closed and close_connection unregisters associated trx from mysql_trx_list. We still might have some non started transactions in mysql_trx_list. Purge threads are an exception, they create their own trx_t objects which are not real transactions but are needed for the purge sys to use the query threads framework. Purge sys shutdown happens at a later point in the shutdown sequence so we need to skip its transactions here. IMPORTANT: If allocating transactions for background threads, please use trx_allocate_for_background. This function does not add the trx to the mysql_trx_list so we don't have to add logic to skip these at shutdown.

Skip purge thread trx, it will be cleared after purge sys shutdown

◆ trx_sys_close()

void trx_sys_close ( void )

Shutdown/Close the transaction system.

◆ trx_sys_create()

void trx_sys_create ( void )

Creates the trx_sys instance and initializes purge_queue and mutex.

◆ trx_sys_create_sys_pages()

void trx_sys_create_sys_pages ( void )

Creates and initializes the transaction system at the database creation.

◆ trx_sys_get_binlog_prepared()

void trx_sys_get_binlog_prepared ( std::vector< trx_id_t > & trx_ids )

Get a list of all binlog prepared transactions.

Parameters

[out] trx_ids all prepared transaction IDs.

◆ trx_sys_get_next_trx_id_or_no()

trx_id_t trx_sys_get_next_trx_id_or_no ( )

inline

Retrieves a next value that will be allocated if trx_sys_allocate_trx_id() or trx_sys_allocate_trx_id_trx_no() was called.

Returns: the next trx->id or trx->no that will be allocated

◆ trx_sys_hdr_page()

static bool trx_sys_hdr_page ( const page_id_t & page_id )

inlinestatic

Checks if a page address is the trx sys header page.

Parameters

[in] page_id page id

Returns: true if trx sys header page

◆ trx_sys_init_at_db_start()

purge_pq_t * trx_sys_init_at_db_start ( void )

Creates and initializes the central memory structures for the transaction system.

This is called when the database is started.

Returns: min binary heap of rsegs to purge

◆ trx_sys_mutex_enter()

static void trx_sys_mutex_enter ( )

inlinestatic

Acquire the trx_sys->mutex.

◆ trx_sys_mutex_exit()

static void trx_sys_mutex_exit ( )

inlinestatic

Release the trx_sys->mutex.

◆ trx_sys_mutex_own()

static bool trx_sys_mutex_own ( )

inlinestatic

Test if trx_sys->mutex is owned.

◆ trx_sys_need_rollback()

static bool trx_sys_need_rollback ( )

inlinestatic

Determine if there are incomplete transactions in the system.

Returns: whether incomplete transactions need rollback

◆ trx_sys_oldest_trx_no()

trx_id_t trx_sys_oldest_trx_no ( )

Returns: oldest transaction number yet to be committed.

◆ trx_sys_persist_gtid_num()

void trx_sys_persist_gtid_num ( trx_id_t gtid_trx_no )

Persist transaction number limit below which all transaction GTIDs are persisted to disk table.

Parameters

[in] gtid_trx_no transaction number

◆ trx_sys_read_binlog_position()

void trx_sys_read_binlog_position	(	char *	file,
		uint64_t &	offset
	)

Get current binary log positions stored.

Parameters

[out]	file	binary log file name
[out]	offset	binary log file offset

◆ trx_sys_recovered_active_trxs_count()

size_t trx_sys_recovered_active_trxs_count ( )

Reads number of recovered transactions which have state equal to TRX_STATE_ACTIVE (so are not prepared transactions).

Returns: number of active recovered transactions

◆ trx_sys_rw_trx_add()

static void trx_sys_rw_trx_add ( trx_t * trx )

inlinestatic

Add the transaction to the RW transaction set.

Parameters

trx	transaction instance to add

◆ trx_sys_serialisation_mutex_enter()

static void trx_sys_serialisation_mutex_enter ( )

inlinestatic

Acquire the trx_sys->serialisation_mutex.

◆ trx_sys_serialisation_mutex_exit()

static void trx_sys_serialisation_mutex_exit ( )

inlinestatic

Release the trx_sys->serialisation_mutex.

◆ trx_sys_serialisation_mutex_own()

static bool trx_sys_serialisation_mutex_own ( )

inlinestatic

Test if trx_sys->serialisation_mutex is owned.

◆ trx_sys_undo_spaces_deinit()

void trx_sys_undo_spaces_deinit ( )

Free the resources occupied by trx_sys_undo_spaces, called once during thread de-initialization.

◆ trx_sys_undo_spaces_init()

void trx_sys_undo_spaces_init ( )

Initialize trx_sys_undo_spaces, called once during srv_start().

◆ trx_sys_update_mysql_binlog_offset()

void trx_sys_update_mysql_binlog_offset	(	trx_t *	trx,
		mtr_t *	mtr
	)

Updates the offset information about the end of the MySQL binlog entry which corresponds to the transaction being committed, external XA transaction being prepared or rolled back.

In a MySQL replication slave updates the latest master binlog position up to which replication has proceeded.

Parameters

[in]	trx	Current transaction
[in,out]	mtr	Mini-transaction for update

◆ trx_sys_validate_trx_list()

bool trx_sys_validate_trx_list ( )

Validate the trx_sys_t::rw_trx_list.

Returns: true if the list is valid; true if the list is valid.

◆ trx_sys_write_binlog_position()

bool trx_sys_write_binlog_position	(	const char *	last_file,
		uint64_t	last_offset,
		const char *	file,
		uint64_t	offset
	)

Update binary log position if not already updated.

This is called by clone to update any stale binary log position if any transaction is yet to update the binary log position in SE.

Parameters

[in]	last_file	last noted binary log file name
[in]	last_offset	last noted binary log offset
[in]	file	current binary log file name
[in]	offset	current binary log file offset

Returns: true, if binary log position is updated with current.

◆ trx_sysf_get()

static trx_sysf_t * trx_sysf_get ( mtr_t * mtr )

inlinestatic

Gets a pointer to the transaction system file copy and x-locks its page.

Returns: pointer to system file copy, page x-locked in: mtr

◆ trx_sysf_rseg_find_free()

ulint trx_sysf_rseg_find_free ( mtr_t * mtr )

Look for a free slot for a rollback segment in the trx system file copy.

Parameters

[in,out] mtr mtr

Returns: slot index or ULINT_UNDEFINED if not found

◆ trx_sysf_rseg_find_page_no()

page_no_t trx_sysf_rseg_find_page_no ( ulint rseg_id )

Find the page number in the TRX_SYS page for a given slot/rseg_id.

Parameters

[in] rseg_id slot number in the TRX_SYS page rseg array

Returns: page number from the TRX_SYS page rseg array

◆ trx_sysf_rseg_get_page_no()

static page_no_t trx_sysf_rseg_get_page_no	(	trx_sysf_t *	sys_header,
		ulint	i,
		mtr_t *	mtr
	)

inlinestatic

Gets the page number of the nth rollback segment slot in the trx system file copy.

Parameters

[in]	sys_header	trx sys file copy
[in]	i	slot index == rseg id
[in]	mtr	mtr

Returns: page number, FIL_NULL if slot unused

◆ trx_sysf_rseg_get_space()

static space_id_t trx_sysf_rseg_get_space	(	trx_sysf_t *	sys_header,
		ulint	i,
		mtr_t *	mtr
	)

inlinestatic

Gets the space of the nth rollback segment slot in the trx system file copy.

Parameters

[in]	sys_header	trx sys file copy
[in]	i	slot index == rseg id
[in]	mtr	mtr

Returns: space id

◆ trx_sysf_rseg_set_page_no()

static void trx_sysf_rseg_set_page_no	(	trx_sysf_t *	sys_header,
		ulint	i,
		page_no_t	page_no,
		mtr_t *	mtr
	)

inlinestatic

Set the page number of the nth rollback segment slot in the trx system file copy.

Parameters

[in]	sys_header	trx sys file copy
[in]	i	slot index == rseg id
[in]	page_no	page number, FIL_NULL if the slot is reset to unused
[in]	mtr	mtr

◆ trx_sysf_rseg_set_space()

static void trx_sysf_rseg_set_space	(	trx_sysf_t *	sys_header,
		ulint	i,
		space_id_t	space,
		mtr_t *	mtr
	)

inlinestatic

Sets the space id of the nth rollback segment slot in the trx system file copy.

Parameters

[in]	sys_header	trx sys file copy
[in]	i	slot index == rseg id
[in]	space	space id
[in]	mtr	mtr

◆ trx_write_trx_id()

static void trx_write_trx_id	(	byte *	ptr,
		trx_id_t	id
	)

inlinestatic

Writes a trx id to an index page.

In case that the id size changes in some future version, this function should be used instead of mach_write_...

Parameters

[in]	ptr	pointer to memory where written
[in]	id	id

Variable Documentation

◆ trx_rseg_n_slots_debug

uint trx_rseg_n_slots_debug

extern

◆ TRX_SHARDS_N

constexpr size_t TRX_SHARDS_N = 256

constexpr

Number of shards created for transactions.

◆ trx_sys

trx_sys_t* trx_sys

extern

The transaction system.

◆ TRX_SYS

constexpr uint32_t TRX_SYS = FSEG_PAGE_DATA

constexpr

The offset of the transaction system header on the page.

◆ TRX_SYS_DOUBLEWRITE_BLOCK1

constexpr uint32_t TRX_SYS_DOUBLEWRITE_BLOCK1 = 4 + FSEG_HEADER_SIZE

constexpr

page number of the first page in the first sequence of 64 (= FSP_EXTENT_SIZE) consecutive pages in the doublewrite buffer

◆ TRX_SYS_DOUBLEWRITE_BLOCK2

constexpr uint32_t TRX_SYS_DOUBLEWRITE_BLOCK2 = 8 + FSEG_HEADER_SIZE

constexpr

page number of the first page in the second sequence of 64 consecutive pages in the doublewrite buffer

◆ TRX_SYS_DOUBLEWRITE_FSEG

constexpr uint32_t TRX_SYS_DOUBLEWRITE_FSEG = 0

constexpr

fseg header of the fseg containing the doublewrite buffer

◆ TRX_SYS_DOUBLEWRITE_MAGIC

constexpr uint32_t TRX_SYS_DOUBLEWRITE_MAGIC = FSEG_HEADER_SIZE

constexpr

4-byte magic number which shows if we already have created the doublewrite buffer

◆ TRX_SYS_DOUBLEWRITE_MAGIC_N

constexpr uint32_t TRX_SYS_DOUBLEWRITE_MAGIC_N = 536853855

constexpr

Contents of TRX_SYS_DOUBLEWRITE_MAGIC.

◆ TRX_SYS_DOUBLEWRITE_REPEAT

constexpr uint32_t TRX_SYS_DOUBLEWRITE_REPEAT = 12

constexpr

we repeat TRX_SYS_DOUBLEWRITE_MAGIC, TRX_SYS_DOUBLEWRITE_BLOCK1, TRX_SYS_DOUBLEWRITE_BLOCK2 so that if the trx sys header is half-written to disk, we still may be able to recover the information

◆ TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED

constexpr uint32_t TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED = 24 + FSEG_HEADER_SIZE

constexpr

If this is not yet set to TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED_N, we must reset the doublewrite buffer, because starting from 4.1.x the space id of a data page is stored into FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID.

◆ TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED_N

constexpr uint32_t TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED_N = 1783657386

constexpr

Contents of TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED.

◆ TRX_SYS_FSEG_HEADER

constexpr uint32_t TRX_SYS_FSEG_HEADER = 8

constexpr

segment header for the tablespace segment the trx system is created into

◆ TRX_SYS_MYSQL_LOG_MAGIC_N

constexpr uint32_t TRX_SYS_MYSQL_LOG_MAGIC_N = 873422344

constexpr

Contents of TRX_SYS_MYSQL_LOG_MAGIC_N_FLD.

◆ TRX_SYS_MYSQL_LOG_MAGIC_N_FLD

constexpr uint32_t TRX_SYS_MYSQL_LOG_MAGIC_N_FLD = 0

constexpr

magic number which is TRX_SYS_MYSQL_LOG_MAGIC_N if we have valid data in the MySQL binlog info

◆ TRX_SYS_MYSQL_LOG_NAME

constexpr uint32_t TRX_SYS_MYSQL_LOG_NAME = 12

constexpr

MySQL log file name.

◆ TRX_SYS_MYSQL_LOG_NAME_LEN

constexpr uint32_t TRX_SYS_MYSQL_LOG_NAME_LEN = 512

constexpr

Maximum length of MySQL binlog file name, in bytes.

◆ TRX_SYS_MYSQL_LOG_OFFSET_HIGH

constexpr uint32_t TRX_SYS_MYSQL_LOG_OFFSET_HIGH = 4

constexpr

high 4 bytes of the offset within that file

◆ TRX_SYS_MYSQL_LOG_OFFSET_LOW

constexpr uint32_t TRX_SYS_MYSQL_LOG_OFFSET_LOW = 8

constexpr

low 4 bytes of the offset within that file

◆ TRX_SYS_OLD_N_RSEGS

constexpr size_t TRX_SYS_OLD_N_RSEGS = 256

constexpr

◆ TRX_SYS_OLD_TMP_RSEGS

constexpr size_t TRX_SYS_OLD_TMP_RSEGS = 32

constexpr

◆ TRX_SYS_RSEGS

constexpr uint32_t TRX_SYS_RSEGS = 8 + FSEG_HEADER_SIZE

constexpr

the start of the array of rollback segment specification slots

◆ TRX_SYS_SYSTEM_RSEG_ID

constexpr uint32_t TRX_SYS_SYSTEM_RSEG_ID = 0

constexpr

The automatically created system rollback segment has this id.

◆ TRX_SYS_TRX_ID_STORE

constexpr uint32_t TRX_SYS_TRX_ID_STORE = 0

constexpr

Transaction system header.

the maximum trx id or trx number modulo TRX_SYS_TRX_ID_UPDATE_MARGIN written to a file page by any transaction; the assignment of transaction ids continues from this number rounded up by TRX_SYS_TRX_ID_UPDATE_MARGIN plus TRX_SYS_TRX_ID_UPDATE_MARGIN when the database is started

◆ TRX_SYS_TRX_ID_WRITE_MARGIN

constexpr trx_id_t TRX_SYS_TRX_ID_WRITE_MARGIN = 256

constexpr

When a trx id which is zero modulo this number (which must be a power of two) is assigned, the field TRX_SYS_TRX_ID_STORE on the transaction system page is updated.

◆ trx_sys_undo_spaces

Space_Ids* trx_sys_undo_spaces

extern

A list of undo tablespace IDs found in the TRX_SYS page.

This cannot be part of the trx_sys_t object because it is initialized before that object is created. These are the old type of undo tablespaces that do not have space_IDs in the reserved range nor contain an RSEG_ARRAY page.

These are the old type of undo tablespaces that do not have space_IDs in the reserved range nor contain an RSEG_ARRAY page. This cannot be part of the trx_sys_t object because it must be built before that is initialized.

Classes

Macros

Functions

Variables

Detailed Description

Macro Definition Documentation

◆ TRX_SYS_DOUBLEWRITE

◆ TRX_SYS_DOUBLEWRITE_BLOCK_SIZE

◆ TRX_SYS_MYSQL_LOG_INFO

◆ TRX_SYS_TRX_NUM_END

◆ TRX_SYS_TRX_NUM_GTID

Function Documentation

◆ trx_get_shard_no()

◆ trx_read_trx_id()

◆ trx_rw_is_active()

◆ trx_sys_after_background_threads_shutdown_validate()

◆ trx_sys_after_pre_dd_shutdown_validate()

◆ trx_sys_allocate_trx_id()

◆ trx_sys_allocate_trx_no()

◆ trx_sys_before_pre_dd_shutdown_validate()

◆ trx_sys_close()

◆ trx_sys_create()

◆ trx_sys_create_sys_pages()

◆ trx_sys_get_binlog_prepared()

◆ trx_sys_get_next_trx_id_or_no()

◆ trx_sys_hdr_page()

◆ trx_sys_init_at_db_start()

◆ trx_sys_mutex_enter()

◆ trx_sys_mutex_exit()

◆ trx_sys_mutex_own()

◆ trx_sys_need_rollback()

◆ trx_sys_oldest_trx_no()

◆ trx_sys_persist_gtid_num()

◆ trx_sys_read_binlog_position()

◆ trx_sys_recovered_active_trxs_count()

◆ trx_sys_rw_trx_add()

◆ trx_sys_serialisation_mutex_enter()

◆ trx_sys_serialisation_mutex_exit()

◆ trx_sys_serialisation_mutex_own()

◆ trx_sys_undo_spaces_deinit()

◆ trx_sys_undo_spaces_init()

◆ trx_sys_update_mysql_binlog_offset()

◆ trx_sys_validate_trx_list()

◆ trx_sys_write_binlog_position()

◆ trx_sysf_get()

◆ trx_sysf_rseg_find_free()

◆ trx_sysf_rseg_find_page_no()

◆ trx_sysf_rseg_get_page_no()

◆ trx_sysf_rseg_get_space()

◆ trx_sysf_rseg_set_page_no()

◆ trx_sysf_rseg_set_space()

◆ trx_write_trx_id()

Variable Documentation

◆ trx_rseg_n_slots_debug

◆ TRX_SHARDS_N

◆ trx_sys

◆ TRX_SYS

◆ TRX_SYS_DOUBLEWRITE_BLOCK1

◆ TRX_SYS_DOUBLEWRITE_BLOCK2

◆ TRX_SYS_DOUBLEWRITE_FSEG

◆ TRX_SYS_DOUBLEWRITE_MAGIC

◆ TRX_SYS_DOUBLEWRITE_MAGIC_N

◆ TRX_SYS_DOUBLEWRITE_REPEAT

◆ TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED

◆ TRX_SYS_DOUBLEWRITE_SPACE_ID_STORED_N

◆ TRX_SYS_FSEG_HEADER

◆ TRX_SYS_MYSQL_LOG_MAGIC_N

◆ TRX_SYS_MYSQL_LOG_MAGIC_N_FLD

◆ TRX_SYS_MYSQL_LOG_NAME

◆ TRX_SYS_MYSQL_LOG_NAME_LEN

◆ TRX_SYS_MYSQL_LOG_OFFSET_HIGH

◆ TRX_SYS_MYSQL_LOG_OFFSET_LOW

◆ TRX_SYS_OLD_N_RSEGS

◆ TRX_SYS_OLD_TMP_RSEGS

◆ TRX_SYS_RSEGS

◆ TRX_SYS_SYSTEM_RSEG_ID

◆ TRX_SYS_TRX_ID_STORE

◆ TRX_SYS_TRX_ID_WRITE_MARGIN

◆ trx_sys_undo_spaces