btr0pcur.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

/******************************************************************
Differs from btr_pcur_commit in that we can specify the mtr to commit. */
UNIV_INLINE
void
btr_pcur_commit_specify_mtr(
/*========================*/
	btr_pcur_t*	pcur,	/* in: persistent cursor */
	mtr_t*		mtr);	/* in: mtr to commit */
/******************************************************************
Tests if a cursor is detached: that is the latch mode is BTR_NO_LATCHES. */
UNIV_INLINE
ibool
btr_pcur_is_detached(
/*=================*/
				/* out: TRUE if detached */
	btr_pcur_t*	pcur);	/* in: persistent cursor */
/*************************************************************
Moves the persistent cursor to the next record in the tree. If no records are
left, the cursor stays 'after last in tree'. */
UNIV_INLINE
ibool
btr_pcur_move_to_next(
/*==================*/
				/* out: TRUE if the cursor was not after last
				in tree */
	btr_pcur_t*	cursor,	/* in: persistent cursor; NOTE that the
				function may release the page latch */
	mtr_t*		mtr);	/* in: mtr */
/*************************************************************
Moves the persistent cursor to the previous record in the tree. If no records
are left, the cursor stays 'before first in tree'. */

ibool
btr_pcur_move_to_prev(
/*==================*/
				/* out: TRUE if the cursor was not before first
				in tree */
	btr_pcur_t*	cursor,	/* in: persistent cursor; NOTE that the
				function may release the page latch */
	mtr_t*		mtr);	/* in: mtr */
/*************************************************************
Moves the persistent cursor to the last record on the same page. */
UNIV_INLINE
void
btr_pcur_move_to_last_on_page(
/*==========================*/
	btr_pcur_t*	cursor,	/* in: persistent cursor */
	mtr_t*		mtr);	/* in: mtr */
/*************************************************************
Moves the persistent cursor to the next user record in the tree. If no user
records are left, the cursor ends up 'after last in tree'. */
UNIV_INLINE
ibool
btr_pcur_move_to_next_user_rec(
/*===========================*/
				/* out: TRUE if the cursor moved forward,
				ending on a user record */
	btr_pcur_t*	cursor,	/* in: persistent cursor; NOTE that the
				function may release the page latch */
	mtr_t*		mtr);	/* in: mtr */
/*************************************************************
Moves the persistent cursor to the first record on the next page.
Releases the latch on the current page, and bufferunfixes it.
Note that there must not be modifications on the current page,
as then the x-latch can be released only in mtr_commit. */

void
btr_pcur_move_to_next_page(
/*=======================*/
	btr_pcur_t*	cursor,	/* in: persistent cursor; must be on the
				last record of the current page */
	mtr_t*		mtr);	/* in: mtr */
/*************************************************************
Moves the persistent cursor backward if it is on the first record
of the page. Releases the latch on the current page, and bufferunfixes
it. Note that to prevent a possible deadlock, the operation first
stores the position of the cursor, releases the leaf latch, acquires
necessary latches and restores the cursor position again before returning.
The alphabetical position of the cursor is guaranteed to be sensible
on return, but it may happen that the cursor is not positioned on the
last record of any page, because the structure of the tree may have
changed while the cursor had no latches. */

void
btr_pcur_move_backward_from_page(
/*=============================*/
	btr_pcur_t*	cursor,	/* in: persistent cursor, must be on the
				first record of the current page */
	mtr_t*		mtr);	/* in: mtr */
/*************************************************************
Returns the btr cursor component of a persistent cursor. */
UNIV_INLINE
btr_cur_t*
btr_pcur_get_btr_cur(
/*=================*/
				/* out: pointer to btr cursor component */
	btr_pcur_t*	cursor);	/* in: persistent cursor */
/*************************************************************
Returns the page cursor component of a persistent cursor. */
UNIV_INLINE
page_cur_t*
btr_pcur_get_page_cur(
/*==================*/
				/* out: pointer to page cursor component */
	btr_pcur_t*	cursor);	/* in: persistent cursor */
/*************************************************************
Returns the page of a persistent cursor. */
UNIV_INLINE
page_t*
btr_pcur_get_page(
/*==============*/
				/* out: pointer to the page */
	btr_pcur_t*	cursor);/* in: persistent cursor */
/*************************************************************
Returns the record of a persistent cursor. */
UNIV_INLINE
rec_t*
btr_pcur_get_rec(
/*=============*/
				/* out: pointer to the record */
	btr_pcur_t*	cursor);/* in: persistent cursor */
/*************************************************************
Checks if the persistent cursor is on a user record. */
UNIV_INLINE
ibool
btr_pcur_is_on_user_rec(
/*====================*/
	btr_pcur_t*	cursor,	/* in: persistent cursor */
	mtr_t*		mtr);	/* in: mtr */
/*************************************************************
Checks if the persistent cursor is after the last user record on 
a page. */
UNIV_INLINE
ibool
btr_pcur_is_after_last_on_page(
/*===========================*/
	btr_pcur_t*	cursor,	/* in: persistent cursor */
	mtr_t*		mtr);	/* in: mtr */
/*************************************************************
Checks if the persistent cursor is before the first user record on 
a page. */
UNIV_INLINE
ibool
btr_pcur_is_before_first_on_page(
/*=============================*/
	btr_pcur_t*	cursor,	/* in: persistent cursor */
	mtr_t*		mtr);	/* in: mtr */
/*************************************************************
Checks if the persistent cursor is before the first user record in
the index tree. */
UNIV_INLINE
ibool
btr_pcur_is_before_first_in_tree(
/*=============================*/
	btr_pcur_t*	cursor,	/* in: persistent cursor */
	mtr_t*		mtr);	/* in: mtr */
/*************************************************************
Checks if the persistent cursor is after the last user record in
the index tree. */
UNIV_INLINE
ibool
btr_pcur_is_after_last_in_tree(
/*===========================*/
	btr_pcur_t*	cursor,	/* in: persistent cursor */
	mtr_t*		mtr);	/* in: mtr */
/*************************************************************
Moves the persistent cursor to the next record on the same page. */
UNIV_INLINE
void
btr_pcur_move_to_next_on_page(
/*==========================*/
	btr_pcur_t*	cursor,	/* in: persistent cursor */
	mtr_t*		mtr);	/* in: mtr */
/*************************************************************
Moves the persistent cursor to the previous record on the same page. */
UNIV_INLINE
void
btr_pcur_move_to_prev_on_page(
/*==========================*/
	btr_pcur_t*	cursor,	/* in: persistent cursor */
	mtr_t*		mtr);	/* in: mtr */


/* The persistent B-tree cursor structure. This is used mainly for SQL
selects, updates, and deletes. */

struct btr_pcur_struct{
	btr_cur_t	btr_cur;	/* a B-tree cursor */
	ulint		latch_mode;	/* see FIXME note below!
					BTR_SEARCH_LEAF, BTR_MODIFY_LEAF,
					BTR_MODIFY_TREE, or BTR_NO_LATCHES,
					depending on the latching state of
					the page and tree where the cursor is
					positioned; the last value means that
					the cursor is not currently positioned:
					we say then that the cursor is
					detached; it can be restored to
					attached if the old position was
					stored in old_rec */
	ulint		old_stored;	/* BTR_PCUR_OLD_STORED
					or BTR_PCUR_OLD_NOT_STORED */
	rec_t*		old_rec;	/* if cursor position is stored,
					contains an initial segment of the
					latest record cursor was positioned
					either on, before, or after */
	ulint		old_n_fields;	/* number of fields in old_rec */
	ulint		rel_pos;	/* BTR_PCUR_ON, BTR_PCUR_BEFORE, or
					BTR_PCUR_AFTER, depending on whether
					cursor was on, before, or after the
					old_rec record */
	buf_block_t*	block_when_stored;/* buffer block when the position was
					stored; note that if AWE is on, frames
					may move */
	dulint		modify_clock;	/* the modify clock value of the
					buffer block when the cursor position
					was stored */
	ulint		pos_state;	/* see FIXME note below!
					BTR_PCUR_IS_POSITIONED,
					BTR_PCUR_WAS_POSITIONED,
					BTR_PCUR_NOT_POSITIONED */
	ulint		search_mode;	/* PAGE_CUR_G, ... */
	trx_t*		trx_if_known;	/* the transaction, if we know it;
					otherwise this field is not defined;
					can ONLY BE USED in error prints in
					fatal assertion failures! */
	/*-----------------------------*/
	/* NOTE that the following fields may possess dynamically allocated
	memory which should be freed if not needed anymore! */

	mtr_t*		mtr;		/* NULL, or this field may contain
					a mini-transaction which holds the
					latch on the cursor page */
	byte*		old_rec_buf;	/* NULL, or a dynamically allocated
					buffer for old_rec */
	ulint		buf_size;	/* old_rec_buf size if old_rec_buf
					is not NULL */
};

#define BTR_PCUR_IS_POSITIONED	1997660512	/* FIXME: currently, the state
						can be BTR_PCUR_IS_POSITIONED,
						though it really should be
						BTR_PCUR_WAS_POSITIONED,
						because we have no obligation
						to commit the cursor with
						mtr; similarly latch_mode may
						be out of date */
#define BTR_PCUR_WAS_POSITIONED	1187549791
#define BTR_PCUR_NOT_POSITIONED 1328997689

#define BTR_PCUR_OLD_STORED	908467085
#define BTR_PCUR_OLD_NOT_STORED	122766467

#ifndef UNIV_NONINL
#include "btr0pcur.ic"
#endif
				
#endif