Transaction system. More...

#include <sys/types.h>
#include <new>
#include "current_thd.h"
#include "ha_prototypes.h"
#include "mysql/plugin.h"
#include "sql_error.h"
#include "trx0sys.h"
#include "fsp0fsp.h"
#include "fsp0sysspace.h"
#include "log0recv.h"
#include "mtr0log.h"
#include "os0file.h"
#include "read0read.h"
#include "srv0srv.h"
#include "srv0start.h"
#include "trx0purge.h"
#include "trx0rseg.h"
#include "trx0trx.h"
#include "trx0undo.h"

Functions
void	trx_sys_write_max_trx_id (void)
	Writes the value of max_trx_id to the file based trx system header. 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...

static bool	read_binlog_position (const byte binlog_buf, const char &file_name, uint32_t &high, uint32_t &low)
	Read binary log positions from buffer passed. More...

static void	write_binlog_position (const char file_name, uint64_t offset, byte binlog_buf, mtr_t *mtr)
	Write binary log position into passed buffer. More...

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

static bool	binlog_position_changed (const char file_name, uint64_t offset, byte binlog_buf)
	Check if binary log position is changed. 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...

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 void	trx_sysf_create (mtr_t *mtr)
	Creates the file page for the transaction system. 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...

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

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...

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...

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

uint	trx_rseg_n_slots_debug = 0

const uint32_t	max_rseg_init_threads = 4

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

Detailed Description

Transaction system.

Created 3/26/1996 Heikki Tuuri

Function Documentation

◆ binlog_position_changed()

static bool binlog_position_changed	(	const char *	file_name,
		uint64_t	offset,
		byte *	binlog_buf
	)

static

Check if binary log position is changed.

Parameters

[in]	file_name	previous binary log file name
[in]	offset	previous binary log file offset
[out]	binlog_buf	buffer from trx sys page to write to

Returns: true, iff binary log position is modified from previous position.

◆ read_binlog_position()

static bool read_binlog_position	(	const byte *	binlog_buf,
		const char *&	file_name,
		uint32_t &	high,
		uint32_t &	low
	)

static

Read binary log positions from buffer passed.

Parameters

[in]	binlog_buf	binary log buffer from trx sys page
[out]	file_name	binary log file name
[out]	high	offset part high order bytes
[out]	low	offset part low order bytes

Returns: true, if buffer has valid binary log position.

◆ 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_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_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_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_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.

◆ 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_sys_write_max_trx_id()

void trx_sys_write_max_trx_id ( void )

Writes the value of max_trx_id to the file based trx system header.

◆ trx_sysf_create()

static void trx_sysf_create ( mtr_t * mtr )

static

Creates the file page for the transaction system.

This function is called only at the database creation, before trx_sys_init.

Parameters

mtr 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

◆ write_binlog_position()

static void write_binlog_position	(	const char *	file_name,
		uint64_t	offset,
		byte *	binlog_buf,
		mtr_t *	mtr
	)

static

Write binary log position into passed buffer.

Parameters

[in]	file_name	Binary log file name
[in]	offset	Binary log offset
[out]	binlog_buf	Buffer from trx sys page to write to
[in,out]	mtr	Mini-transaction

Variable Documentation

◆ max_rseg_init_threads

const uint32_t max_rseg_init_threads = 4

◆ trx_rseg_n_slots_debug

uint trx_rseg_n_slots_debug = 0

◆ trx_sys

trx_sys_t* trx_sys = nullptr

The transaction system.

◆ trx_sys_undo_spaces

Space_Ids* trx_sys_undo_spaces

A list of undo tablespace IDs found in the TRX_SYS 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.

Functions

Variables

Detailed Description

Function Documentation

◆ binlog_position_changed()

◆ read_binlog_position()

◆ trx_sys_after_background_threads_shutdown_validate()

◆ trx_sys_after_pre_dd_shutdown_validate()

◆ 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_init_at_db_start()

◆ trx_sys_oldest_trx_no()

◆ trx_sys_persist_gtid_num()

◆ trx_sys_read_binlog_position()

◆ trx_sys_recovered_active_trxs_count()

◆ 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_sys_write_max_trx_id()

◆ trx_sysf_create()

◆ trx_sysf_rseg_find_free()

◆ trx_sysf_rseg_find_page_no()

◆ write_binlog_position()

Variable Documentation

◆ max_rseg_init_threads

◆ trx_rseg_n_slots_debug

◆ trx_sys

◆ trx_sys_undo_spaces