buf0buf.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

/*   Innobase relational database engine; Copyright (C) 2001 Innobase Oy
     
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License 2
     as published by the Free Software Foundation in June 1991.
     
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
     
     You should have received a copy of the GNU General Public License 2
     along with this program (in file COPYING); if not, write to the Free
     Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
/******************************************************
The database buffer pool high-level routines

(c) 1995 Innobase Oy

Created 11/5/1995 Heikki Tuuri
*******************************************************/

#ifndef buf0buf_h
#define buf0buf_h

#include "univ.i"
#include "fil0fil.h"
#include "mtr0types.h"
#include "buf0types.h"
#include "sync0rw.h"
#include "hash0hash.h"
#include "ut0byte.h"
#include "os0proc.h"

/* Flags for flush types */
#define BUF_FLUSH_LRU		1
#define BUF_FLUSH_SINGLE_PAGE	2
#define BUF_FLUSH_LIST		3	/* An array in the pool struct
					has size BUF_FLUSH_LIST + 1: if you
					add more flush types, put them in
					the middle! */
/* Modes for buf_page_get_gen */
#define BUF_GET			10	/* get always */
#define	BUF_GET_IF_IN_POOL	11	/* get if in pool */
#define	BUF_GET_NOWAIT		12	/* get if can set the latch without
					waiting */
#define BUF_GET_NO_LATCH	14	/* get and bufferfix, but set no latch;
					we have separated this case, because
					it is error-prone programming not to
					set a latch, and it should be used
					with care */
/* Modes for buf_page_get_known_nowait */
#define BUF_MAKE_YOUNG	51
#define BUF_KEEP_OLD	52
/* Magic value to use instead of checksums when they are disabled */
#define BUF_NO_CHECKSUM_MAGIC 0xDEADBEEFUL

extern buf_pool_t* 	buf_pool; 	/* The buffer pool of the database */
#ifdef UNIV_DEBUG
extern ibool		buf_debug_prints;/* If this is set TRUE, the program
					prints info whenever read or flush
					occurs */
#endif /* UNIV_DEBUG */
extern ulint srv_buf_pool_write_requests; /* variable to count write request
                                          issued */

/************************************************************************
Creates the buffer pool. */

buf_pool_t*
buf_pool_init(
/*==========*/
				/* out, own: buf_pool object, NULL if not
				enough memory or error */
	ulint	max_size,	/* in: maximum size of the buf_pool in
				blocks */
	ulint	curr_size,	/* in: current size to use, must be <=
				max_size, currently must be equal to
				max_size */
	ulint	n_frames);	/* in: number of frames; if AWE is used,
				this is the size of the address space window
				where physical memory pages are mapped; if
				AWE is not used then this must be the same
				as max_size */
/*************************************************************************
Gets the current size of buffer buf_pool in bytes. In the case of AWE, the
size of AWE window (= the frames). */
UNIV_INLINE
ulint
buf_pool_get_curr_size(void);
/*========================*/
			/* out: size in bytes */
/*************************************************************************
Gets the maximum size of buffer pool in bytes. In the case of AWE, the
size of AWE window (= the frames). */
UNIV_INLINE
ulint
buf_pool_get_max_size(void);
/*=======================*/
			/* out: size in bytes */
/************************************************************************
Gets the smallest oldest_modification lsn for any page in the pool. Returns
ut_dulint_zero if all modified pages have been flushed to disk. */
UNIV_INLINE
dulint
buf_pool_get_oldest_modification(void);
/*==================================*/
				/* out: oldest modification in pool,
				ut_dulint_zero if none */
/*************************************************************************
Allocates a buffer frame. */

buf_frame_t*
buf_frame_alloc(void);
/*==================*/
				/* out: buffer frame */
/*************************************************************************
Frees a buffer frame which does not contain a file page. */

void
buf_frame_free(
/*===========*/
	buf_frame_t*	frame);	/* in: buffer frame */
/*************************************************************************
Copies contents of a buffer frame to a given buffer. */
UNIV_INLINE
byte*
buf_frame_copy(
/*===========*/
				/* out: buf */
	byte*		buf,	/* in: buffer to copy to */
	buf_frame_t*	frame);	/* in: buffer frame */
/******************************************************************
NOTE! The following macros should be used instead of buf_page_get_gen,
to improve debugging. Only values RW_S_LATCH and RW_X_LATCH are allowed
in LA! */
#define buf_page_get(SP, OF, LA, MTR)    buf_page_get_gen(\
				SP, OF, LA, NULL,\
				BUF_GET, __FILE__, __LINE__, MTR)
/******************************************************************
Use these macros to bufferfix a page with no latching. Remember not to
read the contents of the page unless you know it is safe. Do not modify
the contents of the page! We have separated this case, because it is
error-prone programming not to set a latch, and it should be used
with care. */
#define buf_page_get_with_no_latch(SP, OF, MTR)    buf_page_get_gen(\
				SP, OF, RW_NO_LATCH, NULL,\
				BUF_GET_NO_LATCH, __FILE__, __LINE__, MTR)
/******************************************************************
NOTE! The following macros should be used instead of buf_page_get_gen, to
improve debugging. Only values RW_S_LATCH and RW_X_LATCH are allowed as LA! */
#define buf_page_get_nowait(SP, OF, LA, MTR)    buf_page_get_gen(\
				SP, OF, LA, NULL,\
				BUF_GET_NOWAIT, __FILE__, __LINE__, MTR)
/******************************************************************
NOTE! The following macros should be used instead of
buf_page_optimistic_get_func, to improve debugging. Only values RW_S_LATCH and
RW_X_LATCH are allowed as LA! */
#define buf_page_optimistic_get(LA, BL, G, MC, MTR) buf_page_optimistic_get_func(\
				LA, BL, G, MC, __FILE__, __LINE__, MTR)
/************************************************************************
This is the general function used to get optimistic access to a database
page. */

ibool
buf_page_optimistic_get_func(
/*=========================*/
				/* out: TRUE if success */
	ulint		rw_latch,/* in: RW_S_LATCH, RW_X_LATCH */
	buf_block_t*	block,	/* in: guessed block */
	buf_frame_t*	guess,	/* in: guessed frame; note that AWE may move
				frames */
	dulint		modify_clock,/* in: modify clock value if mode is
				..._GUESS_ON_CLOCK */
	const char*	file,	/* in: file name */
	ulint		line,	/* in: line where called */
	mtr_t*		mtr);	/* in: mini-transaction */
/************************************************************************
Tries to get the page, but if file io is required, releases all latches
in mtr down to the given savepoint. If io is required, this function
retrieves the page to buffer buf_pool, but does not bufferfix it or latch
it. */
UNIV_INLINE
buf_frame_t*
buf_page_get_release_on_io(
/*=======================*/
				/* out: pointer to the frame, or NULL
				if not in buffer buf_pool */
	ulint	space,		/* in: space id */
	ulint	offset,		/* in: offset of the page within space
				in units of a page */
	buf_frame_t* guess,	/* in: guessed frame or NULL */
	ulint	rw_latch,	/* in: RW_X_LATCH, RW_S_LATCH,
				or RW_NO_LATCH */
	ulint	savepoint,	/* in: mtr savepoint */
	mtr_t*	mtr);		/* in: mtr */
/************************************************************************
This is used to get access to a known database page, when no waiting can be
done. */

ibool
buf_page_get_known_nowait(
/*======================*/
				/* out: TRUE if success */
	ulint		rw_latch,/* in: RW_S_LATCH, RW_X_LATCH */
	buf_frame_t*	guess,	/* in: the known page frame */
	ulint		mode,	/* in: BUF_MAKE_YOUNG or BUF_KEEP_OLD */
	const char*	file,	/* in: file name */
	ulint		line,	/* in: line where called */
	mtr_t*		mtr);	/* in: mini-transaction */
/************************************************************************
This is the general function used to get access to a database page. */

buf_frame_t*
buf_page_get_gen(
/*=============*/
				/* out: pointer to the frame or NULL */
	ulint		space,	/* in: space id */
	ulint		offset,	/* in: page number */
	ulint		rw_latch,/* in: RW_S_LATCH, RW_X_LATCH, RW_NO_LATCH */
	buf_frame_t*	guess,	/* in: guessed frame or NULL */
	ulint		mode,	/* in: BUF_GET, BUF_GET_IF_IN_POOL,
				BUF_GET_NO_LATCH */
	const char*	file,	/* in: file name */
	ulint		line,	/* in: line where called */
	mtr_t*		mtr);	/* in: mini-transaction */
/************************************************************************
Initializes a page to the buffer buf_pool. The page is usually not read
from a file even if it cannot be found in the buffer buf_pool. This is one
of the functions which perform to a block a state transition NOT_USED =>
FILE_PAGE (the other is buf_page_init_for_read above). */

buf_frame_t*
buf_page_create(
/*============*/
			/* out: pointer to the frame, page bufferfixed */
	ulint	space,	/* in: space id */
	ulint	offset,	/* in: offset of the page within space in units of
			a page */
	mtr_t*	mtr);	/* in: mini-transaction handle */
/************************************************************************
Inits a page to the buffer buf_pool, for use in ibbackup --restore. */

void
buf_page_init_for_backup_restore(
/*=============================*/
	ulint		space,	/* in: space id */
	ulint		offset,	/* in: offset of the page within space
				in units of a page */
	buf_block_t*	block);	/* in: block to init */
/************************************************************************
Decrements the bufferfix count of a buffer control block and releases
a latch, if specified. */
UNIV_INLINE
void
buf_page_release(
/*=============*/
	buf_block_t*	block,		/* in: buffer block */
	ulint		rw_latch,	/* in: RW_S_LATCH, RW_X_LATCH,
					RW_NO_LATCH */
	mtr_t*		mtr);		/* in: mtr */
/************************************************************************
Moves a page to the start of the buffer pool LRU list. This high-level
function can be used to prevent an important page from from slipping out of
the buffer pool. */

void
buf_page_make_young(
/*=================*/
	buf_frame_t*	frame);	/* in: buffer frame of a file page */
/************************************************************************
Returns TRUE if the page can be found in the buffer pool hash table. NOTE
that it is possible that the page is not yet read from disk, though. */

ibool
buf_page_peek(
/*==========*/
			/* out: TRUE if found from page hash table,
			NOTE that the page is not necessarily yet read
			from disk! */
	ulint	space,	/* in: space id */
	ulint	offset);/* in: page number */
/************************************************************************
Returns the buffer control block if the page can be found in the buffer
pool. NOTE that it is possible that the page is not yet read
from disk, though. This is a very low-level function: use with care! */

buf_block_t*
buf_page_peek_block(
/*================*/
			/* out: control block if found from page hash table,
			otherwise NULL; NOTE that the page is not necessarily
			yet read from disk! */
	ulint	space,	/* in: space id */
	ulint	offset);/* in: page number */
/************************************************************************
Resets the check_index_page_at_flush field of a page if found in the buffer
pool. */

void
buf_reset_check_index_page_at_flush(
/*================================*/
	ulint	space,	/* in: space id */
	ulint	offset);/* in: page number */
/************************************************************************
Sets file_page_was_freed TRUE if the page is found in the buffer pool.
This function should be called when we free a file page and want the
debug version to check that it is not accessed any more unless
reallocated. */

buf_block_t*
buf_page_set_file_page_was_freed(
/*=============================*/
			/* out: control block if found from page hash table,
			otherwise NULL */
	ulint	space,	/* in: space id */
	ulint	offset);	/* in: page number */
/************************************************************************
Sets file_page_was_freed FALSE if the page is found in the buffer pool.
This function should be called when we free a file page and want the
debug version to check that it is not accessed any more unless
reallocated. */

buf_block_t*
buf_page_reset_file_page_was_freed(
/*===============================*/
			/* out: control block if found from page hash table,
			otherwise NULL */
	ulint	space,	/* in: space id */
	ulint	offset);	/* in: page number */
/************************************************************************
Recommends a move of a block to the start of the LRU list if there is danger
of dropping from the buffer pool. NOTE: does not reserve the buffer pool
mutex. */
UNIV_INLINE
ibool
buf_block_peek_if_too_old(
/*======================*/
				/* out: TRUE if should be made younger */
	buf_block_t*	block);	/* in: block to make younger */
/************************************************************************
Returns the current state of is_hashed of a page. FALSE if the page is
not in the pool. NOTE that this operation does not fix the page in the
pool if it is found there. */

ibool
buf_page_peek_if_search_hashed(
/*===========================*/
			/* out: TRUE if page hash index is built in search
			system */
	ulint	space,	/* in: space id */
	ulint	offset);/* in: page number */
/************************************************************************