buf0flu.c

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 database buffer buf_pool flush algorithm

(c) 1995-2001 Innobase Oy

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

#include "buf0flu.h"

#ifdef UNIV_NONINL
#include "buf0flu.ic"
#include "trx0sys.h"
#endif

#include "ut0byte.h"
#include "ut0lst.h"
#include "page0page.h"
#include "fil0fil.h"
#include "buf0buf.h"
#include "buf0lru.h"
#include "buf0rea.h"
#include "ibuf0ibuf.h"
#include "log0log.h"
#include "os0file.h"
#include "trx0sys.h"
#include "srv0srv.h"

/* When flushed, dirty blocks are searched in neigborhoods of this size, and
flushed along with the original page. */

#define BUF_FLUSH_AREA		ut_min(BUF_READ_AHEAD_AREA,\
					       buf_pool->curr_size / 16)

/**********************************************************************
Validates the flush list. */
static
ibool
buf_flush_validate_low(void);
/*========================*/
		/* out: TRUE if ok */

/************************************************************************
Inserts a modified block into the flush list. */

void
buf_flush_insert_into_flush_list(
/*=============================*/
	buf_block_t*	block)	/* in: block which is modified */
{
#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(buf_pool->mutex)));
#endif /* UNIV_SYNC_DEBUG */

	ut_a(block->state == BUF_BLOCK_FILE_PAGE);

	ut_ad((UT_LIST_GET_FIRST(buf_pool->flush_list) == NULL)
	      || (ut_dulint_cmp(
			(UT_LIST_GET_FIRST(buf_pool->flush_list))
						->oldest_modification,
			block->oldest_modification) <= 0));

	UT_LIST_ADD_FIRST(flush_list, buf_pool->flush_list, block);

	ut_ad(buf_flush_validate_low());
}

/************************************************************************
Inserts a modified block into the flush list in the right sorted position.
This function is used by recovery, because there the modifications do not
necessarily come in the order of lsn's. */

void
buf_flush_insert_sorted_into_flush_list(
/*====================================*/
	buf_block_t*	block)	/* in: block which is modified */
{
	buf_block_t*	prev_b;
	buf_block_t*	b;
	
#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(buf_pool->mutex)));
#endif /* UNIV_SYNC_DEBUG */

	prev_b = NULL;
	b = UT_LIST_GET_FIRST(buf_pool->flush_list);

	while (b && (ut_dulint_cmp(b->oldest_modification,
					block->oldest_modification) > 0)) {
		prev_b = b;
		b = UT_LIST_GET_NEXT(flush_list, b);
	}

	if (prev_b == NULL) {
		UT_LIST_ADD_FIRST(flush_list, buf_pool->flush_list, block);
	} else {
		UT_LIST_INSERT_AFTER(flush_list, buf_pool->flush_list, prev_b,
								block);
	}

	ut_ad(buf_flush_validate_low());
}

/************************************************************************
Returns TRUE if the file page block is immediately suitable for replacement,
i.e., the transition FILE_PAGE => NOT_USED allowed. */

ibool
buf_flush_ready_for_replace(
/*========================*/
				/* out: TRUE if can replace immediately */
	buf_block_t*	block)	/* in: buffer control block, must be in state
				BUF_BLOCK_FILE_PAGE and in the LRU list */
{
#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(buf_pool->mutex)));
#endif /* UNIV_SYNC_DEBUG */
	if (block->state != BUF_BLOCK_FILE_PAGE) {
		ut_print_timestamp(stderr);
		fprintf(stderr,
"  InnoDB: Error: buffer block state %lu in the LRU list!\n",
			(ulong)block->state);
		ut_print_buf(stderr, (byte*)block, sizeof(buf_block_t));

		return(FALSE);
	}

	if ((ut_dulint_cmp(block->oldest_modification, ut_dulint_zero) > 0)
	    || (block->buf_fix_count != 0)
	    || (block->io_fix != 0)) {

		return(FALSE);
	}
	
	return(TRUE);
}

/************************************************************************
Returns TRUE if the block is modified and ready for flushing. */
UNIV_INLINE
ibool
buf_flush_ready_for_flush(
/*======================*/
				/* out: TRUE if can flush immediately */
	buf_block_t*	block,	/* in: buffer control block, must be in state
				BUF_BLOCK_FILE_PAGE */
	ulint		flush_type)/* in: BUF_FLUSH_LRU or BUF_FLUSH_LIST */
{
#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(buf_pool->mutex)));
#endif /* UNIV_SYNC_DEBUG */
	ut_a(block->state == BUF_BLOCK_FILE_PAGE);

	if ((ut_dulint_cmp(block->oldest_modification, ut_dulint_zero) > 0)
	    					&& (block->io_fix == 0)) {
	    	if (flush_type != BUF_FLUSH_LRU) {

			return(TRUE);

		} else if (block->buf_fix_count == 0) {
 
			/* If we are flushing the LRU list, to avoid deadlocks
			we require the block not to be bufferfixed, and hence
			not latched. */

			return(TRUE);
		}
	}
	
	return(FALSE);
}

/************************************************************************
Updates the flush system data structures when a write is completed. */

void
buf_flush_write_complete(
/*=====================*/
	buf_block_t*	block)	/* in: pointer to the block in question */
{
	ut_ad(block);
#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&(buf_pool->mutex)));
#endif /* UNIV_SYNC_DEBUG */
	ut_a(block->state == BUF_BLOCK_FILE_PAGE);

	block->oldest_modification = ut_dulint_zero;

	UT_LIST_REMOVE(flush_list, buf_pool->flush_list, block);

	ut_d(UT_LIST_VALIDATE(flush_list, buf_block_t, buf_pool->flush_list));

	(buf_pool->n_flush[block->flush_type])--;

	if (block->flush_type == BUF_FLUSH_LRU) {
		/* Put the block to the end of the LRU list to wait to be
		moved to the free list */

		buf_LRU_make_block_old(block);

		buf_pool->LRU_flush_ended++;
	}

	/* fprintf(stderr, "n pending flush %lu\n",
		buf_pool->n_flush[block->flush_type]); */

	if ((buf_pool->n_flush[block->flush_type] == 0)
	    && (buf_pool->init_flush[block->flush_type] == FALSE)) {

		/* The running flush batch has ended */

		os_event_set(buf_pool->no_flush[block->flush_type]);
	}
}

/************************************************************************
Flushes possible buffered writes from the doublewrite memory buffer to disk,
and also wakes up the aio thread if simulated aio is used. It is very
important to call this function after a batch of writes has been posted,
and also when we may have to wait for a page latch! Otherwise a deadlock
of threads can occur. */
static
void
buf_flush_buffered_writes(void)
/*===========================*/
{
	buf_block_t*	block;
	byte*		write_buf;
	ulint		len;
	ulint		len2;
	ulint		i;

	if (!srv_use_doublewrite_buf || trx_doublewrite == NULL) {
		os_aio_simulated_wake_handler_threads();

		return;
	}
	
	mutex_enter(&(trx_doublewrite->mutex));

	/* Write first to doublewrite buffer blocks. We use synchronous
	aio and thus know that file write has been completed when the
	control returns. */

	if (trx_doublewrite->first_free == 0) {

		mutex_exit(&(trx_doublewrite->mutex));

		return;
	}

	for (i = 0; i < trx_doublewrite->first_free; i++) {

		block = trx_doublewrite->buf_block_arr[i];
	        ut_a(block->state == BUF_BLOCK_FILE_PAGE);

		if (mach_read_from_4(block->frame + FIL_PAGE_LSN + 4)
                            != mach_read_from_4(block->frame + UNIV_PAGE_SIZE
                                        - FIL_PAGE_END_LSN_OLD_CHKSUM + 4)) {
                            ut_print_timestamp(stderr);
                            fprintf(stderr,
"  InnoDB: ERROR: The page to be written seems corrupt!\n"
"InnoDB: The lsn fields do not match! Noticed in the buffer pool\n"
"InnoDB: before posting to the doublewrite buffer.\n");
                }

		if (block->check_index_page_at_flush
				&& !page_simple_validate(block->frame)) {

			buf_page_print(block->frame);

			ut_print_timestamp(stderr);
			fprintf(stderr,
	"  InnoDB: Apparent corruption of an index page n:o %lu in space %lu\n"
	"InnoDB: to be written to data file. We intentionally crash server\n"
	"InnoDB: to prevent corrupt data from ending up in data\n"
	"InnoDB: files.\n",
			(ulong) block->offset, (ulong) block->space);

			ut_error;
		}
	}

        /* increment the doublewrite flushed pages counter */
        srv_dblwr_pages_written+= trx_doublewrite->first_free;
        srv_dblwr_writes++;
        
	if (trx_doublewrite->first_free > TRX_SYS_DOUBLEWRITE_BLOCK_SIZE) {
		len = TRX_SYS_DOUBLEWRITE_BLOCK_SIZE * UNIV_PAGE_SIZE;
	} else {
		len = trx_doublewrite->first_free * UNIV_PAGE_SIZE;
	}
	
	fil_io(OS_FILE_WRITE,
		TRUE, TRX_SYS_SPACE,
		trx_doublewrite->block1, 0, len,
		 	(void*)trx_doublewrite->write_buf, NULL);
	
	write_buf = trx_doublewrite->write_buf;

        for (len2 = 0; len2 + UNIV_PAGE_SIZE <= len; len2 += UNIV_PAGE_SIZE) {
        	if (mach_read_from_4(write_buf + len2 + FIL_PAGE_LSN + 4)
                    != mach_read_from_4(write_buf + len2 + UNIV_PAGE_SIZE
                                        - FIL_PAGE_END_LSN_OLD_CHKSUM + 4)) {
			ut_print_timestamp(stderr);
			fprintf(stderr,
"  InnoDB: ERROR: The page to be written seems corrupt!\n"
"InnoDB: The lsn fields do not match! Noticed in the doublewrite block1.\n");
		}
	}

	if (trx_doublewrite->first_free > TRX_SYS_DOUBLEWRITE_BLOCK_SIZE) {
		len = (trx_doublewrite->first_free
			- TRX_SYS_DOUBLEWRITE_BLOCK_SIZE) * UNIV_PAGE_SIZE;
	
		fil_io(OS_FILE_WRITE,
			TRUE, TRX_SYS_SPACE,
			trx_doublewrite->block2, 0, len,
		 	(void*)(trx_doublewrite->write_buf
		 	+ TRX_SYS_DOUBLEWRITE_BLOCK_SIZE * UNIV_PAGE_SIZE),
			NULL);

		write_buf = trx_doublewrite->write_buf
			   + TRX_SYS_DOUBLEWRITE_BLOCK_SIZE * UNIV_PAGE_SIZE;
		for (len2 = 0; len2 + UNIV_PAGE_SIZE <= len;
						len2 += UNIV_PAGE_SIZE) {
        		if (mach_read_from_4(write_buf + len2
							+ FIL_PAGE_LSN + 4)
                    	    != mach_read_from_4(write_buf + len2
					+ UNIV_PAGE_SIZE
                                        - FIL_PAGE_END_LSN_OLD_CHKSUM + 4)) {
				ut_print_timestamp(stderr);
				fprintf(stderr,
"  InnoDB: ERROR: The page to be written seems corrupt!\n"
"InnoDB: The lsn fields do not match! Noticed in the doublewrite block2.\n");
			}
		}
	}

	/* Now flush the doublewrite buffer data to disk */

	fil_flush(TRX_SYS_SPACE);

	/* We know that the writes have been flushed to disk now
	and in recovery we will find them in the doublewrite buffer
	blocks. Next do the writes to the intended positions. */

	for (i = 0; i < trx_doublewrite->first_free; i++) {
		block = trx_doublewrite->buf_block_arr[i];

		if (mach_read_from_4(block->frame + FIL_PAGE_LSN + 4)
                            != mach_read_from_4(block->frame + UNIV_PAGE_SIZE
                                        - FIL_PAGE_END_LSN_OLD_CHKSUM + 4)) {
                            ut_print_timestamp(stderr);
                            fprintf(stderr,
"  InnoDB: ERROR: The page to be written seems corrupt!\n"
"InnoDB: The lsn fields do not match! Noticed in the buffer pool\n"
"InnoDB: after posting and flushing the doublewrite buffer.\n"
"InnoDB: Page buf fix count %lu, io fix %lu, state %lu\n",
			(ulong)block->buf_fix_count, (ulong)block->io_fix,
			(ulong)block->state);
                }
		ut_a(block->state == BUF_BLOCK_FILE_PAGE);

		fil_io(OS_FILE_WRITE | OS_AIO_SIMULATED_WAKE_LATER,
			FALSE, block->space, block->offset, 0, UNIV_PAGE_SIZE,
		 			(void*)block->frame, (void*)block);
	}
	
	/* Wake possible simulated aio thread to actually post the
	writes to the operating system */

	os_aio_simulated_wake_handler_threads();

	/* Wait that all async writes to tablespaces have been posted to
	the OS */	
	
	os_aio_wait_until_no_pending_writes();

	/* Now we flush the data to disk (for example, with fsync) */

	fil_flush_file_spaces(FIL_TABLESPACE);

	/* We can now reuse the doublewrite memory buffer: */

	trx_doublewrite->first_free = 0;

	mutex_exit(&(trx_doublewrite->mutex));	
}

/************************************************************************
Posts a buffer page for writing. If the doublewrite memory buffer is
full, calls buf_flush_buffered_writes and waits for for free space to
appear. */
static
void
buf_flush_post_to_doublewrite_buf(
/*==============================*/
	buf_block_t*	block)	/* in: buffer block to write */
{
try_again:
	mutex_enter(&(trx_doublewrite->mutex));

	ut_a(block->state == BUF_BLOCK_FILE_PAGE);

	if (trx_doublewrite->first_free
				>= 2 * TRX_SYS_DOUBLEWRITE_BLOCK_SIZE) {
		mutex_exit(&(trx_doublewrite->mutex));

		buf_flush_buffered_writes();

		goto try_again;
	}

	ut_memcpy(trx_doublewrite->write_buf
				+ UNIV_PAGE_SIZE * trx_doublewrite->first_free,
			block->frame, UNIV_PAGE_SIZE);

	trx_doublewrite->buf_block_arr[trx_doublewrite->first_free] = block;

	trx_doublewrite->first_free++;

	if (trx_doublewrite->first_free
				>= 2 * TRX_SYS_DOUBLEWRITE_BLOCK_SIZE) {
		mutex_exit(&(trx_doublewrite->mutex));

		buf_flush_buffered_writes();

		return;
	}

	mutex_exit(&(trx_doublewrite->mutex));
}

/************************************************************************
Initializes a page for writing to the tablespace. */

void
buf_flush_init_for_writing(
/*=======================*/
	byte*	page,		/* in: page */
	dulint	newest_lsn,	/* in: newest modification lsn to the page */
	ulint	space,		/* in: space id */
	ulint	page_no)	/* in: page number */
{	
	/* Write the newest modification lsn to the page header and trailer */
	mach_write_to_8(page + FIL_PAGE_LSN, newest_lsn);

	mach_write_to_8(page + UNIV_PAGE_SIZE - FIL_PAGE_END_LSN_OLD_CHKSUM,
								newest_lsn);
	/* Write the page number and the space id */

	mach_write_to_4(page + FIL_PAGE_OFFSET, page_no);
        mach_write_to_4(page + FIL_PAGE_ARCH_LOG_NO_OR_SPACE_ID, space);

	/* Store the new formula checksum */

	mach_write_to_4(page + FIL_PAGE_SPACE_OR_CHKSUM,
					srv_use_checksums ?
                  buf_calc_page_new_checksum(page) : BUF_NO_CHECKSUM_MAGIC);

	/* We overwrite the first 4 bytes of the end lsn field to store
	the old formula checksum. Since it depends also on the field
	FIL_PAGE_SPACE_OR_CHKSUM, it has to be calculated after storing the
	new formula checksum. */

	mach_write_to_4(page + UNIV_PAGE_SIZE - FIL_PAGE_END_LSN_OLD_CHKSUM,
					srv_use_checksums ?
                  buf_calc_page_old_checksum(page) : BUF_NO_CHECKSUM_MAGIC);
}

/************************************************************************
Does an asynchronous write of a buffer page. NOTE: in simulated aio and
also when the doublewrite buffer is used, we must call
buf_flush_buffered_writes after we have posted a batch of writes! */
static
void
buf_flush_write_block_low(
/*======================*/
	buf_block_t*	block)	/* in: buffer block to write */
{
#ifdef UNIV_LOG_DEBUG
	static ibool univ_log_debug_warned;
#endif /* UNIV_LOG_DEBUG */
	ut_a(block->state == BUF_BLOCK_FILE_PAGE);

#ifdef UNIV_IBUF_DEBUG
	ut_a(ibuf_count_get(block->space, block->offset) == 0);
#endif
	ut_ad(!ut_dulint_is_zero(block->newest_modification));

#ifdef UNIV_LOG_DEBUG
	if (!univ_log_debug_warned) {
		univ_log_debug_warned = TRUE;
		fputs(
	"Warning: cannot force log to disk if UNIV_LOG_DEBUG is defined!\n"
	"Crash recovery will not work!\n",
			stderr);
	}
#else
	/* Force the log to the disk before writing the modified block */
	log_write_up_to(block->newest_modification, LOG_WAIT_ALL_GROUPS, TRUE);
#endif	
	buf_flush_init_for_writing(block->frame, block->newest_modification,
						block->space, block->offset);
	if (!srv_use_doublewrite_buf || !trx_doublewrite) {
		fil_io(OS_FILE_WRITE | OS_AIO_SIMULATED_WAKE_LATER,
			FALSE, block->space, block->offset, 0, UNIV_PAGE_SIZE,
		 			(void*)block->frame, (void*)block);
	} else {
		buf_flush_post_to_doublewrite_buf(block);
	}
}

/************************************************************************
Writes a page asynchronously from the buffer buf_pool to a file, if it can be
found in the buf_pool and it is in a flushable state. NOTE: in simulated aio
we must call os_aio_simulated_wake_handler_threads after we have posted a batch
of writes! */
static
ulint
buf_flush_try_page(
/*===============*/
				/* out: 1 if a page was flushed, 0 otherwise */
	ulint	space,		/* in: space id */
	ulint	offset,		/* in: page offset */
	ulint	flush_type)	/* in: BUF_FLUSH_LRU, BUF_FLUSH_LIST, or
				BUF_FLUSH_SINGLE_PAGE */
{
	buf_block_t*	block;
	ibool		locked;
	
	ut_ad(flush_type == BUF_FLUSH_LRU || flush_type == BUF_FLUSH_LIST