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

/******************************************************
The index tree persistent cursor

(c) 1996 Innobase Oy

Created 2/23/1996 Heikki Tuuri
*******************************************************/

#ifndef btr0pcur_h
#define btr0pcur_h

#include "univ.i"
#include "dict0dict.h"
#include "data0data.h"
#include "mtr0mtr.h"
#include "page0cur.h"
#include "btr0cur.h"
#include "btr0btr.h"
#include "btr0types.h"

/* Relative positions for a stored cursor position */
#define BTR_PCUR_ON			1
#define BTR_PCUR_BEFORE			2
#define BTR_PCUR_AFTER			3
/* Note that if the tree is not empty, btr_pcur_store_position does not
use the following, but only uses the above three alternatives, where the
position is stored relative to a specific record: this makes implementation
of a scroll cursor easier */
#define BTR_PCUR_BEFORE_FIRST_IN_TREE	4	/* in an empty tree */
#define BTR_PCUR_AFTER_LAST_IN_TREE	5	/* in an empty tree */

/******************************************************************
Allocates memory for a persistent cursor object and initializes the cursor. */

btr_pcur_t*
btr_pcur_create_for_mysql(void);
/*============================*/
				/* out, own: persistent cursor */
/******************************************************************
Frees the memory for a persistent cursor object. */

void
btr_pcur_free_for_mysql(
/*====================*/
	btr_pcur_t*	cursor);	/* in, own: persistent cursor */
/******************************************************************
Copies the stored position of a pcur to another pcur. */

void
btr_pcur_copy_stored_position(
/*==========================*/
	btr_pcur_t*	pcur_receive,	/* in: pcur which will receive the
					position info */
	btr_pcur_t*	pcur_donate);	/* in: pcur from which the info is
					copied */
/******************************************************************
Sets the old_rec_buf field to NULL. */
UNIV_INLINE
void
btr_pcur_init(
/*==========*/
	btr_pcur_t*	pcur);	/* in: persistent cursor */
/******************************************************************
Initializes and opens a persistent cursor to an index tree. It should be
closed with btr_pcur_close. */
UNIV_INLINE
void
btr_pcur_open(
/*==========*/
	dict_index_t*	index,	/* in: index */
	dtuple_t*	tuple,	/* in: tuple on which search done */
	ulint		mode,	/* in: PAGE_CUR_L, ...;
				NOTE that if the search is made using a unique
				prefix of a record, mode should be
				PAGE_CUR_LE, not PAGE_CUR_GE, as the latter
				may end up on the previous page from the
				record! */
	ulint		latch_mode,/* in: BTR_SEARCH_LEAF, ... */
	btr_pcur_t*	cursor, /* in: memory buffer for persistent cursor */
	mtr_t*		mtr);	/* in: mtr */
/******************************************************************
Opens an persistent cursor to an index tree without initializing the
cursor. */
UNIV_INLINE
void
btr_pcur_open_with_no_init(
/*=======================*/
	dict_index_t*	index,	/* in: index */
	dtuple_t*	tuple,	/* in: tuple on which search done */
	ulint		mode,	/* in: PAGE_CUR_L, ...;
				NOTE that if the search is made using a unique
				prefix of a record, mode should be
				PAGE_CUR_LE, not PAGE_CUR_GE, as the latter
				may end up on the previous page of the
				record! */
	ulint		latch_mode,/* in: BTR_SEARCH_LEAF, ...;
				NOTE that if has_search_latch != 0 then
				we maybe do not acquire a latch on the cursor
				page, but assume that the caller uses his
				btr search latch to protect the record! */
	btr_pcur_t*	cursor, /* in: memory buffer for persistent cursor */
	ulint		has_search_latch,/* in: latch mode the caller
				currently has on btr_search_latch:
				RW_S_LATCH, or 0 */
	mtr_t*		mtr);	/* in: mtr */
/*********************************************************************
Opens a persistent cursor at either end of an index. */
UNIV_INLINE
void
btr_pcur_open_at_index_side(
/*========================*/
	ibool		from_left,	/* in: TRUE if open to the low end,
					FALSE if to the high end */
	dict_index_t*	index,		/* in: index */
	ulint		latch_mode,	/* in: latch mode */
	btr_pcur_t*	pcur,		/* in: cursor */
	ibool		do_init,	/* in: TRUE if should be initialized */
	mtr_t*		mtr);		/* in: mtr */
/******************************************************************
Gets the up_match value for a pcur after a search. */
UNIV_INLINE
ulint
btr_pcur_get_up_match(
/*==================*/
				/* out: number of matched fields at the cursor
				or to the right if search mode was PAGE_CUR_GE,
				otherwise undefined */
	btr_pcur_t*	cursor); /* in: memory buffer for persistent cursor */
/******************************************************************
Gets the low_match value for a pcur after a search. */
UNIV_INLINE
ulint
btr_pcur_get_low_match(
/*===================*/
				/* out: number of matched fields at the cursor
				or to the right if search mode was PAGE_CUR_LE,
				otherwise undefined */
	btr_pcur_t*	cursor); /* in: memory buffer for persistent cursor */
/******************************************************************
If mode is PAGE_CUR_G or PAGE_CUR_GE, opens a persistent cursor on the first
user record satisfying the search condition, in the case PAGE_CUR_L or
PAGE_CUR_LE, on the last user record. If no such user record exists, then
in the first case sets the cursor after last in tree, and in the latter case
before first in tree. The latching mode must be BTR_SEARCH_LEAF or
BTR_MODIFY_LEAF. */

void
btr_pcur_open_on_user_rec(
/*======================*/
	dict_index_t*	index,		/* in: index */
	dtuple_t*	tuple,		/* in: tuple on which search done */
	ulint		mode,		/* in: PAGE_CUR_L, ... */
	ulint		latch_mode,	/* in: BTR_SEARCH_LEAF or
					BTR_MODIFY_LEAF */
	btr_pcur_t*	cursor, 	/* in: memory buffer for persistent
					cursor */
	mtr_t*		mtr);		/* in: mtr */
/**************************************************************************
Positions a cursor at a randomly chosen position within a B-tree. */
UNIV_INLINE
void
btr_pcur_open_at_rnd_pos(
/*=====================*/
	dict_index_t*	index,		/* in: index */
	ulint		latch_mode,	/* in: BTR_SEARCH_LEAF, ... */
	btr_pcur_t*	cursor,		/* in/out: B-tree pcur */
	mtr_t*		mtr);		/* in: mtr */
/******************************************************************
Frees the possible old_rec_buf buffer of a persistent cursor and sets the
latch mode of the persistent cursor to BTR_NO_LATCHES. */
UNIV_INLINE
void
btr_pcur_close(
/*===========*/
	btr_pcur_t*	cursor);	/* in: persistent cursor */
/******************************************************************
The position of the cursor is stored by taking an initial segment of the
record the cursor is positioned on, before, or after, and copying it to the
cursor data structure, or just setting a flag if the cursor id before the
first in an EMPTY tree, or after the last in an EMPTY tree. NOTE that the
page where the cursor is positioned must not be empty if the index tree is
not totally empty! */

void
btr_pcur_store_position(
/*====================*/
	btr_pcur_t*	cursor, /* in: persistent cursor */
	mtr_t*		mtr);	/* in: mtr */
/******************************************************************
Restores the stored position of a persistent cursor bufferfixing the page and
obtaining the specified latches. If the cursor position was saved when the
(1) cursor was positioned on a user record: this function restores the position
to the last record LESS OR EQUAL to the stored record;
(2) cursor was positioned on a page infimum record: restores the position to
the last record LESS than the user record which was the successor of the page
infimum;
(3) cursor was positioned on the page supremum: restores to the first record
GREATER than the user record which was the predecessor of the supremum.
(4) cursor was positioned before the first or after the last in an empty tree:
restores to before first or after the last in the tree. */

ibool
btr_pcur_restore_position(
/*======================*/
					/* out: TRUE if the cursor position
					was stored when it was on a user record
					and it can be restored on a user record
					whose ordering fields are identical to
					the ones of the original user record */
	ulint		latch_mode,	/* in: BTR_SEARCH_LEAF, ... */
	btr_pcur_t*	cursor, 	/* in: detached persistent cursor */
	mtr_t*		mtr);		/* in: mtr */
/******************************************************************
If the latch mode of the cursor is BTR_LEAF_SEARCH or BTR_LEAF_MODIFY,
releases the page latch and bufferfix reserved by the cursor.
NOTE! In the case of BTR_LEAF_MODIFY, there should not exist changes
made by the current mini-transaction to the data protected by the
cursor latch, as then the latch must not be released until mtr_commit. */

void
btr_pcur_release_leaf(
/*==================*/
	btr_pcur_t*	cursor, /* in: persistent cursor */
	mtr_t*		mtr);	/* in: mtr */
/*************************************************************
Gets the rel_pos field for a cursor whose position has been stored. */
UNIV_INLINE
ulint
btr_pcur_get_rel_pos(
/*=================*/
				/* out: BTR_PCUR_ON, ... */
	btr_pcur_t*	cursor);/* in: persistent cursor */
/*************************************************************
Sets the mtr field for a pcur. */
UNIV_INLINE
void
btr_pcur_set_mtr(
/*=============*/
	btr_pcur_t*	cursor,	/* in: persistent cursor */
	mtr_t*		mtr);	/* in, own: mtr */
/*************************************************************
Gets the mtr field for a pcur. */
UNIV_INLINE
mtr_t*
btr_pcur_get_mtr(
/*=============*/
				/* out: mtr */
	btr_pcur_t*	cursor);	/* in: persistent cursor */
/******************************************************************
Commits the pcur mtr and sets the pcur latch mode to BTR_NO_LATCHES,
that is, the cursor becomes detached. If there have been modifications
to the page where pcur is positioned, this can be used instead of
btr_pcur_release_leaf. Function btr_pcur_store_position should be used
before calling this, if restoration of cursor is wanted later. */
UNIV_INLINE
void
btr_pcur_commit(
/*============*/
	btr_pcur_t*	pcur);	/* in: persistent cursor */