trx0undo.cc File Reference

Transaction undo log. More...

#include <stddef.h>
#include <sql_thd_internal_api.h>
#include "fsp0fsp.h"
#include "ha_prototypes.h"
#include "trx0undo.h"
#include "my_dbug.h"
#include "clone0clone.h"
#include "current_thd.h"
#include "dict0dd.h"
#include "fil0fil.h"
#include "log0chkp.h"
#include "log0write.h"
#include "mach0data.h"
#include "mtr0log.h"
#include "srv0mon.h"
#include "srv0srv.h"
#include "srv0start.h"
#include "trx0purge.h"
#include "trx0rec.h"
#include "trx0rseg.h"
#include "trx0trx.h"

Functions
static void	trx_undo_page_init (page_t *undo_page, ulint type, mtr_t *mtr)
	Initializes the fields in an undo log segment page. More...
static trx_undo_t *	trx_undo_mem_create (trx_rseg_t *rseg, ulint id, ulint type, trx_id_t trx_id, const XID *xid, page_no_t page_no, ulint offset)
	Creates and initializes an undo log memory object. More...
static ulint	trx_undo_insert_header_reuse (page_t *undo_page, trx_id_t trx_id, mtr_t *mtr)
	Initializes a cached insert undo log header page for new use. More...
static trx_undo_rec_t *	trx_undo_get_prev_rec_from_prev_page (trx_undo_rec_t *rec, page_no_t page_no, ulint offset, bool shared, mtr_t *mtr)
	Gets the previous record in an undo log from the previous page. More...
trx_undo_rec_t *	trx_undo_get_prev_rec (trx_undo_rec_t *rec, page_no_t page_no, ulint offset, bool shared, mtr_t *mtr)
	Gets the previous record in an undo log. More...
static trx_undo_rec_t *	trx_undo_get_next_rec_from_next_page (space_id_t space, const page_size_t &page_size, const page_t *undo_page, page_no_t page_no, ulint offset, ulint mode, mtr_t *mtr)
	Gets the next record in an undo log from the next page. More...
trx_undo_rec_t *	trx_undo_get_next_rec (trx_undo_rec_t *rec, page_no_t page_no, ulint offset, mtr_t *mtr)
	Gets the next record in an undo log. More...
trx_undo_rec_t *	trx_undo_get_first_rec (trx_id_t *modifier_trx_id, space_id_t space, const page_size_t &page_size, page_no_t page_no, ulint offset, ulint mode, mtr_t *mtr)
	Gets the first record in an undo log. More...
static void	trx_undo_page_init_log (page_t *undo_page, ulint type, mtr_t *mtr)
	Writes the mtr log entry of an undo log page initialization. More...
byte *	trx_undo_parse_page_init (const byte *ptr, const byte *end_ptr, page_t *page, mtr_t *mtr)
	Parses the redo log entry of an undo log page initialization. More...
static dberr_t	trx_undo_seg_create (trx_rseg_t *rseg, trx_rsegf_t *rseg_hdr, ulint type, ulint *id, page_t **undo_page, mtr_t *mtr)
	Creates a new undo log segment in file. More...
static void	trx_undo_header_create_log (const page_t *undo_page, trx_id_t trx_id, mtr_t *mtr)
	Writes the mtr log entry of an undo log header initialization. More...
static ulint	trx_undo_header_create (page_t *undo_page, trx_id_t trx_id, mtr_t *mtr)
	Creates a new undo log header in file. More...
static void	trx_undo_write_xid (trx_ulogf_t *log_hdr, const XID *xid, mtr_t *mtr)
	Write X/Open XA Transaction Identification (XID) to undo log header. More...
dberr_t	trx_undo_gtid_add_update_undo (trx_t *trx, bool prepare, bool rollback)
	For saving GTID add update undo slot, if required. More...
void	trx_undo_gtid_set (trx_t *trx, trx_undo_t *undo, bool is_xa_prepare)
	Set GTID flag in undo if transaction has GTID/. More...
void	trx_undo_gtid_read_and_persist (trx_ulogf_t *undo_header)
	Read and persist GTID from undo header during recovery. More...
void	trx_undo_gtid_write (trx_t *trx, trx_ulogf_t *undo_header, trx_undo_t *undo, mtr_t *mtr, bool is_xa_prepare)
	Write GTID information to undo log header. More...
static void	trx_undo_read_xid (trx_ulogf_t *log_hdr, XID *xid)
	Read X/Open XA Transaction Identification (XID) from undo log header. More...
static void	trx_undo_header_add_space_for_xid (page_t *undo_page, trx_ulogf_t *log_hdr, mtr_t *mtr, trx_undo_t::Gtid_storage gtid_storage)
	Adds space for the XA XID after an undo log old-style header. More...
static void	trx_undo_insert_header_reuse_log (const page_t *undo_page, trx_id_t trx_id, mtr_t *mtr)
	Writes the mtr log entry of an undo log header reuse. More...
byte *	trx_undo_parse_page_header (mlog_id_t type, const byte *ptr, const byte *end_ptr, page_t *page, mtr_t *mtr)
	Parse the redo log entry of an undo log page header create or reuse. More...
buf_block_t *	trx_undo_add_page (trx_t *trx, trx_undo_t *undo, trx_undo_ptr_t *undo_ptr, mtr_t *mtr)
	Tries to add a page to the undo log segment where the undo log is placed. More...
static page_no_t	trx_undo_free_page (trx_rseg_t *rseg, bool in_history, space_id_t space, page_no_t hdr_page_no, page_no_t page_no, mtr_t *mtr)
	Frees an undo log page that is not the header page. More...
void	trx_undo_free_last_page_func (const trx_t *trx, trx_undo_t *undo, mtr_t *mtr)
	Frees the last undo log page. More...
static void	trx_undo_empty_header_page (space_id_t space_id, const page_size_t &page_size, page_no_t hdr_page_no, ulint hdr_offset, mtr_t *mtr)
	Empties an undo log header page of undo records for that undo log. More...
int	trx_undo_page_truncate_offset (trx_undo_t *undo, page_t *undo_page, undo_no_t limit)
	Get page offset up to which undo logs can be truncated. More...
void	trx_undo_truncate_end_func (const trx_t *trx, trx_undo_t *undo, undo_no_t limit)
	Truncates an undo log from the end. More...
void	trx_undo_truncate_start (trx_rseg_t *rseg, page_no_t hdr_page_no, ulint hdr_offset, undo_no_t limit)
	Truncate the head of an undo log. More...
static void	trx_undo_seg_free (const trx_undo_t *undo, bool noredo)
	Frees an undo log segment which is not in the history list. More...
static trx_undo_t *	trx_undo_mem_init (trx_rseg_t *rseg, ulint id, page_no_t page_no, mtr_t *mtr)
	Creates and initializes an undo log memory object for a newly created rseg. More...
ulint	trx_undo_lists_init (trx_rseg_t *rseg)
	Initializes the undo log lists for a rollback segment memory copy. More...
static void	trx_undo_mem_init_for_reuse (trx_undo_t *undo, trx_id_t trx_id, const XID *xid, ulint offset)
	Initializes a cached undo log object for new use. More...
void	trx_undo_mem_free (trx_undo_t *undo)
	Frees an undo log memory copy. More...
static dberr_t	trx_undo_create (trx_rseg_t *rseg, ulint type, trx_id_t trx_id, const XID *xid, trx_undo_t::Gtid_storage gtid_storage, trx_undo_t **undo, mtr_t *mtr)
	Create a new undo log in the given rollback segment. More...
static trx_undo_t *	trx_undo_reuse_cached (trx_rseg_t *rseg, ulint type, trx_id_t trx_id, const XID *xid, trx_undo_t::Gtid_storage gtid_storage, mtr_t *mtr)
	Reuses a cached undo log. More...
static void	trx_undo_mark_as_dict_operation (trx_undo_t *undo, mtr_t *mtr)
	Marks an undo log header as a header of a data dictionary operation transaction. More...
dberr_t	trx_undo_assign_undo (trx_t *trx, trx_undo_ptr_t *undo_ptr, ulint type)
	Assigns an undo log for a transaction. More...
page_t *	trx_undo_set_state_at_finish (trx_undo_t *undo, mtr_t *mtr)
	Sets the state of the undo log segment at a transaction finish. More...
page_t *	trx_undo_set_state_at_prepare (trx_t *trx, trx_undo_t *undo, bool rollback, mtr_t *mtr)
	Set the state of the undo log segment at a XA PREPARE or XA ROLLBACK. More...
page_t *	trx_undo_set_prepared_in_tc (trx_t *trx, trx_undo_t *undo, mtr_t *mtr)
	Set the state of the undo log segment as prepared in TC. More...
void	trx_undo_update_cleanup (trx_t *trx, trx_undo_ptr_t *undo_ptr, page_t *undo_page, bool update_rseg_history_len, ulint n_added_logs, mtr_t *mtr)
	Adds the update undo log header as the first in the history list, and frees the memory object, or puts it to the list of cached update undo log segments. More...
void	trx_undo_insert_cleanup (trx_undo_ptr_t *undo_ptr, bool noredo)
	Frees an insert undo log after a transaction commit or rollback. More...
void	trx_undo_free_trx_with_prepared_or_active_logs (trx_t *trx, bool prepared)
	At shutdown, frees the undo logs of a transaction which was either PREPARED or (ACTIVE and recovered). More...
bool	trx_undo_truncate_tablespace (undo::Tablespace *marked_space)
	Truncate UNDO tablespace, reinitialize header and rseg. More...

Detailed Description

Transaction undo log.

Created 3/26/1996 Heikki Tuuri

Function Documentation

trx_undo_add_page()

buf_block_t * trx_undo_add_page	(	trx_t *	trx,
		trx_undo_t *	undo,
		trx_undo_ptr_t *	undo_ptr,
		mtr_t *	mtr
	)

Tries to add a page to the undo log segment where the undo log is placed.

Returns

X-latched block if success, else NULL

Parameters

trx	in: transaction
undo	in: undo log memory object
undo_ptr	in: assign undo log from referred rollback segment.
mtr	in: mtr which does not have a latch to any undo log page; the caller must have reserved the rollback segment mutex

trx_undo_assign_undo()

dberr_t trx_undo_assign_undo	(	trx_t *	trx,
		trx_undo_ptr_t *	undo_ptr,
		ulint	type
	)

Assigns an undo log for a transaction.

A new undo log is created or a cached undo log reused.

Returns

DB_SUCCESS if undo log assign successful, possible error codes are: DB_TOO_MANY_CONCURRENT_TRXS DB_OUT_OF_FILE_SPACE DB_READ_ONLY DB_OUT_OF_MEMORY

Parameters

trx	in: transaction
undo_ptr	in: assign undo log from referred rollback segment.
type	in: TRX_UNDO_INSERT or TRX_UNDO_UPDATE

trx_undo_create()

static dberr_t trx_undo_create ( trx_rseg_t *  rseg, ulint  type, trx_id_t  trx_id, const XID *  xid, trx_undo_t::Gtid_storage  gtid_storage, trx_undo_t **  undo, mtr_t *  mtr  )

static

Create a new undo log in the given rollback segment.

Parameters

[in]	rseg	rollback segment memory copy
[in]	type	type of the log: TRX_UNDO_INSERT or TRX_UNDO_UPDATE
[in]	trx_id	id of the trx for which the undo log is created
[in]	xid	X/Open transaction identification
[in]	gtid_storage	GTID storage type
[out]	undo	the new undo log object, undefined if did not succeed
[in]	mtr	mini-transation

Return values

DB_SUCCESS	if successful in creating the new undo lob object,
DB_TOO_MANY_CONCURRENT_TRXS	too many concurrent trxs
DB_OUT_OF_FILE_SPACE	out of file-space
DB_OUT_OF_MEMORY	out of memory

trx_undo_empty_header_page()

static void trx_undo_empty_header_page ( space_id_t  space_id, const page_size_t &  page_size, page_no_t  hdr_page_no, ulint  hdr_offset, mtr_t *  mtr  )

static

Empties an undo log header page of undo records for that undo log.

Other undo logs may still have records on that page, if it is an update undo log.

Parameters

[in]	space_id	Tablespace ID
[in]	page_size	Page size
[in]	hdr_page_no	Header page number
[in]	hdr_offset	Header offset
[in,out]	mtr	Mini-transaction

trx_undo_free_last_page_func()

void trx_undo_free_last_page_func	(	const trx_t *	trx,
		trx_undo_t *	undo,
		mtr_t *	mtr
	)

Frees the last undo log page.

The caller must hold the rollback segment mutex.

Parameters

[in]	trx	transaction
[in,out]	undo	undo log memory copy
[in,out]	mtr	mini-transaction which does not have a latch to any undo log page or which has allocated the undo log page

trx_undo_free_page()

static page_no_t trx_undo_free_page ( trx_rseg_t *  rseg, bool  in_history, space_id_t  space, page_no_t  hdr_page_no, page_no_t  page_no, mtr_t *  mtr  )

static

Frees an undo log page that is not the header page.

Returns

last page number in remaining log

Parameters

rseg	in: rollback segment
in_history	in: true if the undo log is in the history list
space	in: space
hdr_page_no	in: header page number
page_no	in: page number to free: must not be the header page
mtr	in: mtr which does not have a latch to any undo log page; the caller must have reserved the rollback segment mutex

trx_undo_free_trx_with_prepared_or_active_logs()

void trx_undo_free_trx_with_prepared_or_active_logs	(	trx_t *	trx,
		bool	prepared
	)

At shutdown, frees the undo logs of a transaction which was either PREPARED or (ACTIVE and recovered).

Parameters

[in]	trx	transaction which undo logs are freed
[in]	prepared	whether or not the undo segment is in prepared or prepared in tc states

trx_undo_get_first_rec()

trx_undo_rec_t * trx_undo_get_first_rec	(	trx_id_t *	modifier_trx_id,
		space_id_t	space,
		const page_size_t &	page_size,
		page_no_t	page_no,
		ulint	offset,
		ulint	mode,
		mtr_t *	mtr
	)

Gets the first record in an undo log.

Parameters

[out]	modifier_trx_id	The modifier trx identifier.
[in]	space	Undo log header space
[in]	page_size	Page size
[in]	page_no	Undo log header page number
[in]	offset	Undo log header offset on page
[in]	mode	Latching mode: RW_S_LATCH or RW_X_LATCH
[in,out]	mtr	Mini-transaction

Returns

undo log record, the page latched, NULL if none

trx_undo_get_next_rec()

trx_undo_rec_t * trx_undo_get_next_rec	(	trx_undo_rec_t *	rec,
		page_no_t	page_no,
		ulint	offset,
		mtr_t *	mtr
	)

Gets the next record in an undo log.

Returns

undo log record, the page s-latched, NULL if none

Parameters

rec	in: undo record
page_no	in: undo log header page number
offset	in: undo log header offset on page
mtr	in: mtr

trx_undo_get_next_rec_from_next_page()

static trx_undo_rec_t * trx_undo_get_next_rec_from_next_page ( space_id_t  space, const page_size_t &  page_size, const page_t *  undo_page, page_no_t  page_no, ulint  offset, ulint  mode, mtr_t *  mtr  )

static

Gets the next record in an undo log from the next page.

Parameters

[in]	space	Undo log header space
[in]	page_size	Page size
[in]	undo_page	Undo log page
[in]	page_no	Undo log header page number
[in]	offset	Undo log header offset on page
[in]	mode	Latch mode: RW_S_LATCH or RW_X_LATCH
[in,out]	mtr	Mini-transaction

Returns

undo log record, the page latched, NULL if none

trx_undo_get_prev_rec()

trx_undo_rec_t * trx_undo_get_prev_rec	(	trx_undo_rec_t *	rec,
		page_no_t	page_no,
		ulint	offset,
		bool	shared,
		mtr_t *	mtr
	)

Gets the previous record in an undo log.

Returns

undo log record, the page s-latched, NULL if none

Parameters

rec	in: undo record
page_no	in: undo log header page number
offset	in: undo log header offset on page
shared	in: true=S-latch, false=X-latch
mtr	in: mtr

trx_undo_get_prev_rec_from_prev_page()

static trx_undo_rec_t * trx_undo_get_prev_rec_from_prev_page ( trx_undo_rec_t *  rec, page_no_t  page_no, ulint  offset, bool  shared, mtr_t *  mtr  )

static

Gets the previous record in an undo log from the previous page.

Returns

undo log record, the page s-latched, NULL if none

Parameters

rec	in: undo record
page_no	in: undo log header page number
offset	in: undo log header offset on page
shared	in: true=S-latch, false=X-latch
mtr	in: mtr

trx_undo_gtid_add_update_undo()

dberr_t trx_undo_gtid_add_update_undo	(	trx_t *	trx,
		bool	prepare,
		bool	rollback
	)

For saving GTID add update undo slot, if required.

Parameters

[in]	trx	transaction
[in]	prepare	operation is prepare
[in]	rollback	operation is rollback

Returns

innodb error code.

trx_undo_gtid_read_and_persist()

void trx_undo_gtid_read_and_persist

(

trx_ulogf_t *

undo_log

)

Read and persist GTID from undo header during recovery.

Parameters

[in]

undo_log

undo log header

trx_undo_gtid_set()

void trx_undo_gtid_set	(	trx_t *	trx,
		trx_undo_t *	undo,
		bool	is_xa_prepare
	)

Set GTID flag in undo if transaction has GTID/.

Parameters

[in,out]	trx	transaction
[in,out]	undo	undo log memory object
[in]	is_xa_prepare	GTID is for XA prepared transaction.

trx_undo_gtid_write()

void trx_undo_gtid_write	(	trx_t *	trx,
		trx_ulogf_t *	undo_header,
		trx_undo_t *	undo,
		mtr_t *	mtr,
		bool	is_xa_prepare
	)

Write GTID information to undo log header.

Parameters

[in,out]	trx	transaction
[in,out]	undo_header	undo log header
[in,out]	undo	undo log memory object
[in,out]	mtr	minit transaction for write
[in]	is_xa_prepare	GTID is for XA prepared transaction.

trx_undo_header_add_space_for_xid()

static void trx_undo_header_add_space_for_xid ( page_t *  undo_page, trx_ulogf_t *  log_hdr, mtr_t *  mtr, trx_undo_t::Gtid_storage  gtid_storage  )

static

Adds space for the XA XID after an undo log old-style header.

Parameters

[in,out]	undo_page	Undo log segment header page
[in,out]	log_hdr	Undo log header
[in,out]	mtr	Mini-transaction
[in]	gtid_storage	GTID storage type

trx_undo_header_create()

static ulint trx_undo_header_create ( page_t *  undo_page, trx_id_t  trx_id, mtr_t *  mtr  )

static

Creates a new undo log header in file.

NOTE that this function has its own log record type MLOG_UNDO_HDR_CREATE. You must NOT change the operation of this function!

Returns

header byte offset on page

Parameters

undo_page	in/out: undo log segment header page, x-latched; it is assumed that there is TRX_UNDO_LOG_HDR_SIZE bytes free space on it
trx_id	in: transaction id
mtr	in: mtr

trx_undo_header_create_log()

static void trx_undo_header_create_log ( const page_t *  undo_page, trx_id_t  trx_id, mtr_t *  mtr  )

inlinestatic

Writes the mtr log entry of an undo log header initialization.

Parameters

undo_page	in: undo log header page
trx_id	in: transaction id
mtr	in: mtr

trx_undo_insert_cleanup()

void trx_undo_insert_cleanup	(	trx_undo_ptr_t *	undo_ptr,
		bool	noredo
	)

Frees an insert undo log after a transaction commit or rollback.

Knowledge of inserts is not needed after a commit or rollback, therefore the data can be discarded.

Parameters

[in,out]	undo_ptr	undo log to clean up
[in]	noredo	whether the undo tablespace is redo logged

trx_undo_insert_header_reuse()

static ulint trx_undo_insert_header_reuse ( page_t *  undo_page, trx_id_t  trx_id, mtr_t *  mtr  )

static

Initializes a cached insert undo log header page for new use.

NOTE that this function has its own log record type MLOG_UNDO_HDR_REUSE. You must NOT change the operation of this function!

Returns

undo log header byte offset on page in: mtr

NOTE that this function has its own log record type MLOG_UNDO_HDR_REUSE. You must NOT change the operation of this function!

Returns

undo log header byte offset on page

Parameters

undo_page	in/out: insert undo log segment header page, x-latched
trx_id	in: transaction id
mtr	in: mtr

trx_undo_insert_header_reuse_log()

static void trx_undo_insert_header_reuse_log ( const page_t *  undo_page, trx_id_t  trx_id, mtr_t *  mtr  )

inlinestatic

Writes the mtr log entry of an undo log header reuse.

Parameters

undo_page	in: undo log header page
trx_id	in: transaction id
mtr	in: mtr

trx_undo_lists_init()

ulint trx_undo_lists_init

(

trx_rseg_t *

rseg

)

Initializes the undo log lists for a rollback segment memory copy.

This function is only called when the database is started or a new rollback segment is created.

Returns

the combined size of undo log segments in pages

Parameters

rseg	in: rollback segment memory object

trx_undo_mark_as_dict_operation()

static void trx_undo_mark_as_dict_operation ( trx_undo_t *  undo, mtr_t *  mtr  )

static

Marks an undo log header as a header of a data dictionary operation transaction.

Parameters

undo	in: assigned undo log
mtr	in: mtr

trx_undo_mem_create()

static trx_undo_t * trx_undo_mem_create ( trx_rseg_t *  rseg, ulint  id, ulint  type, trx_id_t  trx_id, const XID *  xid, page_no_t  page_no, ulint  offset  )

static

Creates and initializes an undo log memory object.

Parameters

[in]	rseg	rollback segment memory object
[in]	id	slot index within rseg
[in]	type	type of the log: TRX_UNDO_INSERT or TRX_UNDO_UPDATE
[in]	trx_id	id of the trx for which the undo log is created
[in]	xid	X/Open XA transaction identification
[in]	page_no	undo log header page number
[in]	offset	undo log header byte offset on page

Returns

own: the undo log memory object

trx_undo_mem_free()

void trx_undo_mem_free

(

trx_undo_t *

undo

)

Frees an undo log memory copy.

Parameters

undo	in: the undo object to be freed

trx_undo_mem_init()

static trx_undo_t * trx_undo_mem_init ( trx_rseg_t *  rseg, ulint  id, page_no_t  page_no, mtr_t *  mtr  )

static

Creates and initializes an undo log memory object for a newly created rseg.

The memory object is inserted in the appropriate list in the rseg.

Returns

own: the undo log memory object

Parameters

rseg	in: rollback segment memory object
id	in: slot index within rseg
page_no	in: undo log segment page number
mtr	in: mtr

trx_undo_mem_init_for_reuse()

static void trx_undo_mem_init_for_reuse ( trx_undo_t *  undo, trx_id_t  trx_id, const XID *  xid, ulint  offset  )

static

Initializes a cached undo log object for new use.

Parameters

undo	in: undo log to init
trx_id	in: id of the trx for which the undo log is created
xid	in: X/Open XA transaction identification
offset	in: undo log header byte offset on page

trx_undo_page_init()

static void trx_undo_page_init ( page_t *  undo_page, ulint  type, mtr_t *  mtr  )

static

Initializes the fields in an undo log segment page.

in: mtr

Parameters

undo_page	in: undo log segment page
type	in: undo log segment type
mtr	in: mtr

trx_undo_page_init_log()

static void trx_undo_page_init_log ( page_t *  undo_page, ulint  type, mtr_t *  mtr  )

inlinestatic

Writes the mtr log entry of an undo log page initialization.

Parameters

undo_page	in: undo log page
type	in: undo log type
mtr	in: mtr

trx_undo_page_truncate_offset()

int trx_undo_page_truncate_offset	(	trx_undo_t *	undo,
		page_t *	undo_page,
		undo_no_t	limit
	)

Get page offset up to which undo logs can be truncated.

There are three possibilities.

1. Truncate nothing on this page. Return -1
2. Truncate part of the page. Return the offset
3. Truncate the whole page. Return 0

   Parameters

   [in]	undo	undo log to truncate
   [in]	undo_page	undo log page to check
   [in]	limit	limit up to which undo logs to be truncated

   Returns

   page offset to truncate to, 0 for whole page, -1 for nothing.

trx_undo_parse_page_header()

byte * trx_undo_parse_page_header	(	mlog_id_t	type,
		const byte *	ptr,
		const byte *	end_ptr,
		page_t *	page,
		mtr_t *	mtr
	)

Parse the redo log entry of an undo log page header create or reuse.

Parameters

[in]	type	MLOG_UNDO_HDR_CREATE or MLOG_UNDO_HDR_REUSE
[in]	ptr	Redo log record
[in]	end_ptr	End of log buffer
[in,out]	page	Page frame or NULL
[in,out]	mtr	Mini-transaction or NULL

Returns

end of log record or NULL

trx_undo_parse_page_init()

byte * trx_undo_parse_page_init	(	const byte *	ptr,
		const byte *	end_ptr,
		page_t *	page,
		mtr_t *	mtr
	)

Parses the redo log entry of an undo log page initialization.

Returns

end of log record or NULL

Parameters

ptr	in: buffer
end_ptr	in: buffer end
page	in: page or NULL
mtr	in: mtr or NULL

trx_undo_read_xid()

static void trx_undo_read_xid ( trx_ulogf_t *  log_hdr, XID *  xid  )

static

Read X/Open XA Transaction Identification (XID) from undo log header.

Parameters

log_hdr	in: undo log header
xid	out: X/Open XA Transaction Identification

trx_undo_reuse_cached()

static trx_undo_t * trx_undo_reuse_cached ( trx_rseg_t *  rseg, ulint  type, trx_id_t  trx_id, const XID *  xid, trx_undo_t::Gtid_storage  gtid_storage, mtr_t *  mtr  )

static

Reuses a cached undo log.

Parameters

[in,out]	rseg	Rollback segment memory object
[in]	type	Type of the log: TRX_UNDO_INSERT or TRX_UNDO_UPDATE
[in]	trx_id	Id of the trx for which the undo log is used
[in]	xid	X/Open XA transaction identification
[in]	gtid_storage	GTID storage type
[in,out]	mtr	Mini-transaction

Returns

the undo log memory object, NULL if none cached

trx_undo_seg_create()

static dberr_t trx_undo_seg_create ( trx_rseg_t *  rseg, trx_rsegf_t *  rseg_hdr, ulint  type, ulint *  id, page_t **  undo_page, mtr_t *  mtr  )

static

Creates a new undo log segment in file.

Returns

DB_SUCCESS if page creation OK possible error codes are: DB_TOO_MANY_CONCURRENT_TRXS DB_OUT_OF_FILE_SPACE

Parameters

rseg	in: rollback segment
rseg_hdr	in: rollback segment header, page x-latched
type	in: type of the segment: TRX_UNDO_INSERT or TRX_UNDO_UPDATE
id	out: slot index within rseg header
undo_page	out: segment header page x-latched, NULL if there was an error
mtr	in: mtr

trx_undo_seg_free()

static void trx_undo_seg_free ( const trx_undo_t *  undo, bool  noredo  )

static

Frees an undo log segment which is not in the history list.

Parameters

[in]	undo	undo log
[in]	noredo	whether the undo tablespace is redo logged

trx_undo_set_prepared_in_tc()

page_t * trx_undo_set_prepared_in_tc	(	trx_t *	trx,
		trx_undo_t *	undo,
		mtr_t *	mtr
	)

Set the state of the undo log segment as prepared in TC.

Parameters

[in,out]	trx	Transaction
[in,out]	undo	Insert_undo or update_undo log
[in,out]	mtr	Mini-transaction

Returns

undo log segment header page, x-latched

trx_undo_set_state_at_finish()

page_t * trx_undo_set_state_at_finish	(	trx_undo_t *	undo,
		mtr_t *	mtr
	)

Sets the state of the undo log segment at a transaction finish.

Returns

undo log segment header page, x-latched

Parameters

undo	in: undo log memory copy
mtr	in: mtr

trx_undo_set_state_at_prepare()

page_t * trx_undo_set_state_at_prepare	(	trx_t *	trx,
		trx_undo_t *	undo,
		bool	rollback,
		mtr_t *	mtr
	)

Set the state of the undo log segment at a XA PREPARE or XA ROLLBACK.

Parameters

[in,out]	trx	Transaction
[in,out]	undo	Insert_undo or update_undo log
[in]	rollback	false=XA PREPARE, true=XA ROLLBACK
[in,out]	mtr	Mini-transaction

Returns

undo log segment header page, x-latched

trx_undo_truncate_end_func()

void trx_undo_truncate_end_func	(	const trx_t *	trx,
		trx_undo_t *	undo,
		undo_no_t	limit
	)

Truncates an undo log from the end.

This function is used during a rollback to free space from an undo log.

Parameters

[in]	trx	transaction for this undo log
[in]	undo	undo log
[in]	limit	all undo records with undo number; This value should be truncated.

trx_undo_truncate_start()

void trx_undo_truncate_start	(	trx_rseg_t *	rseg,
		page_no_t	hdr_page_no,
		ulint	hdr_offset,
		undo_no_t	limit
	)

Truncate the head of an undo log.

NOTE that only whole pages are freed; the header page is not freed, but emptied, if all the records there are below the limit.

Parameters

[in,out]	rseg	rollback segment
[in]	hdr_page_no	header page number
[in]	hdr_offset	header offset on the page
[in]	limit	first undo number to preserve (everything below the limit will be truncated)

trx_undo_truncate_tablespace()

bool trx_undo_truncate_tablespace

(

undo::Tablespace *

marked_space

)

Truncate UNDO tablespace, reinitialize header and rseg.

Parameters

[in]

marked_space

UNDO tablespace to truncate

Returns

true if success else false.

trx_undo_update_cleanup()

void trx_undo_update_cleanup	(	trx_t *	trx,
		trx_undo_ptr_t *	undo_ptr,
		page_t *	undo_page,
		bool	update_rseg_history_len,
		ulint	n_added_logs,
		mtr_t *	mtr
	)

Adds the update undo log header as the first in the history list, and frees the memory object, or puts it to the list of cached update undo log segments.

Parameters

[in]	trx	Trx owning the update undo log
[in]	undo_ptr	Update undo log.
[in]	undo_page	Update undo log header page, x-latched
[in]	update_rseg_history_len	If true: update rseg history len else skip updating it.
[in]	n_added_logs	Number of logs added
[in]	mtr	Mini-transaction

trx_undo_write_xid()

static void trx_undo_write_xid ( trx_ulogf_t *  log_hdr, const XID *  xid, mtr_t *  mtr  )

static

Write X/Open XA Transaction Identification (XID) to undo log header.

Parameters

log_hdr	in: undo log header
xid	in: X/Open XA Transaction Identification
mtr	in: mtr