trx0undo.h

这是linux下运行的mysql软件包,可用于linux 下安装 php + mysql + apach 的网络配置

/******************************************************
Transaction undo log

(c) 1996 Innobase Oy

Created 3/26/1996 Heikki Tuuri
*******************************************************/

#ifndef trx0undo_h
#define trx0undo_h

#include "univ.i"
#include "trx0types.h"
#include "mtr0mtr.h"
#include "trx0sys.h"
#include "page0types.h"
#include "trx0xa.h"

/***************************************************************************
Builds a roll pointer dulint. */
UNIV_INLINE
dulint
trx_undo_build_roll_ptr(
/*====================*/
				/* out: roll pointer */
	ibool	is_insert,	/* in: TRUE if insert undo log */
	ulint	rseg_id,	/* in: rollback segment id */
	ulint	page_no,	/* in: page number */
	ulint	offset);		/* in: offset of the undo entry within page */
/***************************************************************************
Decodes a roll pointer dulint. */
UNIV_INLINE
void
trx_undo_decode_roll_ptr(
/*=====================*/
	dulint	roll_ptr,	/* in: roll pointer */
	ibool*	is_insert,	/* out: TRUE if insert undo log */
	ulint*	rseg_id,	/* out: rollback segment id */
	ulint*	page_no,	/* out: page number */
	ulint*	offset);	/* out: offset of the undo entry within page */
/***************************************************************************
Returns TRUE if the roll pointer is of the insert type. */
UNIV_INLINE
ibool
trx_undo_roll_ptr_is_insert(
/*========================*/
				/* out: TRUE if insert undo log */
	dulint	roll_ptr);	/* in: roll pointer */
/*********************************************************************
Writes a roll ptr to an index page. In case that the size changes in
some future version, this function should be used instead of
mach_write_... */
UNIV_INLINE
void
trx_write_roll_ptr(
/*===============*/
	byte*	ptr,		/* in: pointer to memory where written */
	dulint	roll_ptr);	/* in: roll ptr */
/*********************************************************************
Reads a roll ptr from an index page. In case that the roll ptr size
changes in some future version, this function should be used instead of
mach_read_... */
UNIV_INLINE
dulint
trx_read_roll_ptr(
/*==============*/
			/* out: roll ptr */
	byte*	ptr);	/* in: pointer to memory from where to read */
/**********************************************************************
Gets an undo log page and x-latches it. */
UNIV_INLINE
page_t*
trx_undo_page_get(
/*===============*/
				/* out: pointer to page x-latched */
	ulint	space,		/* in: space where placed */
	ulint	page_no,	/* in: page number */
	mtr_t*	mtr);		/* in: mtr */
/**********************************************************************
Gets an undo log page and s-latches it. */
UNIV_INLINE
page_t*
trx_undo_page_get_s_latched(
/*=========================*/
				/* out: pointer to page s-latched */
	ulint	space,		/* in: space where placed */
	ulint	page_no,	/* in: page number */
	mtr_t*	mtr);		/* in: mtr */
/**********************************************************************
Returns the previous undo record on the page in the specified log, or
NULL if none exists. */
UNIV_INLINE
trx_undo_rec_t*
trx_undo_page_get_prev_rec(
/*=======================*/
				/* out: pointer to record, NULL if none */
	trx_undo_rec_t*	rec,	/* in: undo log record */
	ulint		page_no,/* in: undo log header page number */
	ulint		offset);	/* in: undo log header offset on page */
/**********************************************************************
Returns the next undo log record on the page in the specified log, or
NULL if none exists. */
UNIV_INLINE
trx_undo_rec_t*
trx_undo_page_get_next_rec(
/*=======================*/
				/* out: pointer to record, NULL if none */
	trx_undo_rec_t*	rec,	/* in: undo log record */
	ulint		page_no,/* in: undo log header page number */
	ulint		offset);	/* in: undo log header offset on page */
/**********************************************************************
Returns the last undo record on the page in the specified undo log, or
NULL if none exists. */
UNIV_INLINE
trx_undo_rec_t*
trx_undo_page_get_last_rec(
/*=======================*/
			/* out: pointer to record, NULL if none */
	page_t*	undo_page,/* in: undo log page */
	ulint	page_no,/* in: undo log header page number */
	ulint	offset);	/* in: undo log header offset on page */
/**********************************************************************
Returns the first undo record on the page in the specified undo log, or
NULL if none exists. */
UNIV_INLINE
trx_undo_rec_t*
trx_undo_page_get_first_rec(
/*========================*/
			/* out: pointer to record, NULL if none */
	page_t*	undo_page,/* in: undo log page */
	ulint	page_no,/* in: undo log header page number */
	ulint	offset);	/* in: undo log header offset on page */
/***************************************************************************
Gets the previous record in an undo log. */

trx_undo_rec_t*
trx_undo_get_prev_rec(
/*==================*/
				/* out: undo log record, the page s-latched,
				NULL if none */
	trx_undo_rec_t*	rec,	/* in: undo record */
	ulint		page_no,/* in: undo log header page number */
	ulint		offset,	/* in: undo log header offset on page */
	mtr_t*		mtr);	/* in: mtr */
/***************************************************************************
Gets the next record in an undo log. */

trx_undo_rec_t*
trx_undo_get_next_rec(
/*==================*/
				/* out: undo log record, the page s-latched,
				NULL if none */
	trx_undo_rec_t*	rec,	/* in: undo record */
	ulint		page_no,/* in: undo log header page number */
	ulint		offset,	/* in: undo log header offset on page */
	mtr_t*		mtr);	/* in: mtr */
/***************************************************************************
Gets the first record in an undo log. */

trx_undo_rec_t*
trx_undo_get_first_rec(
/*===================*/
			/* out: undo log record, the page latched, NULL if
			none */
	ulint	space,	/* in: undo log header space */	
	ulint	page_no,/* in: undo log header page number */
	ulint	offset,	/* in: undo log header offset on page */
	ulint	mode,	/* in: latching mode: RW_S_LATCH or RW_X_LATCH */
	mtr_t*	mtr);	/* in: mtr */
/************************************************************************
Tries to add a page to the undo log segment where the undo log is placed. */

ulint
trx_undo_add_page(
/*==============*/
				/* out: page number if success, else
				FIL_NULL */
	trx_t*		trx,	/* in: transaction */
	trx_undo_t*	undo,	/* in: undo log memory object */
	mtr_t*		mtr);	/* in: mtr which does not have a latch to any
				undo log page; the caller must have reserved
				the rollback segment mutex */
/***************************************************************************
Truncates an undo log from the end. This function is used during a rollback
to free space from an undo log. */

void
trx_undo_truncate_end(
/*==================*/
	trx_t*		trx,	/* in: transaction whose undo log it is */
	trx_undo_t*	undo,	/* in: undo log */
	dulint		limit);	/* in: all undo records with undo number
				>= this value should be truncated */
/***************************************************************************
Truncates an undo log from the start. This function is used during a purge
operation. */

void
trx_undo_truncate_start(
/*====================*/
	trx_rseg_t* rseg,	/* in: rollback segment */
	ulint	space,		/* in: space id of the log */
	ulint	hdr_page_no,	/* in: header page number */
	ulint	hdr_offset,	/* in: header offset on the page */
	dulint	limit);		/* in: all undo pages with undo numbers <
				this value should be truncated; NOTE that
				the function only frees whole pages; the
				header page is not freed, but emptied, if
				all the records there are < limit */
/************************************************************************
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 created. */

ulint
trx_undo_lists_init(
/*================*/
				/* out: the combined size of undo log segments
				in pages */
	trx_rseg_t*	rseg);	/* in: rollback segment memory object */	
/**************************************************************************
Assigns an undo log for a transaction. A new undo log is created or a cached
undo log reused. */

trx_undo_t*
trx_undo_assign_undo(
/*=================*/
			/* out: the undo log, NULL if did not succeed: out of
			space */
	trx_t*	trx,	/* in: transaction */
	ulint	type);	/* in: TRX_UNDO_INSERT or TRX_UNDO_UPDATE */
/**********************************************************************
Sets the state of the undo log segment at a transaction finish. */

page_t*
trx_undo_set_state_at_finish(
/*=========================*/
				/* out: undo log segment header page,
				x-latched */
	trx_t*		trx,	/* in: transaction */
	trx_undo_t*	undo,	/* in: undo log memory copy */
	mtr_t*		mtr);	/* in: mtr */
/**********************************************************************
Sets the state of the undo log segment at a transaction prepare. */

page_t*
trx_undo_set_state_at_prepare(
/*==========================*/
				/* out: undo log segment header page,
				x-latched */