ibuf0ibuf.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

	dtuple_set_types_binary(tuple, 1);

	return(tuple);
}

/*************************************************************************
Builds a search tuple used to search buffered inserts for an index page.
This is for >= 4.1.x format records. */
static
dtuple_t*
ibuf_new_search_tuple_build(
/*========================*/
				/* out, own: search tuple */
	ulint		space,	/* in: space id */
	ulint		page_no,/* in: index page number */
	mem_heap_t*	heap)	/* in: heap into which to build */
{
	dtuple_t*	tuple;
	dfield_t*	field;
	byte*		buf;
	
	ut_a(trx_sys_multiple_tablespace_format);

	tuple = dtuple_create(heap, 3);

	/* Store the space id in tuple */

	field = dtuple_get_nth_field(tuple, 0);

	buf = mem_heap_alloc(heap, 4);

	mach_write_to_4(buf, space);

	dfield_set_data(field, buf, 4);

	/* Store the new format record marker byte */

	field = dtuple_get_nth_field(tuple, 1);

	buf = mem_heap_alloc(heap, 1);

	mach_write_to_1(buf, 0);

	dfield_set_data(field, buf, 1);

	/* Store the page number in tuple */

	field = dtuple_get_nth_field(tuple, 2);

	buf = mem_heap_alloc(heap, 4);

	mach_write_to_4(buf, page_no);

	dfield_set_data(field, buf, 4);

	dtuple_set_types_binary(tuple, 3);

	return(tuple);
}

/*************************************************************************
Checks if there are enough pages in the free list of the ibuf tree that we
dare to start a pessimistic insert to the insert buffer. */
UNIV_INLINE
ibool
ibuf_data_enough_free_for_insert(
/*=============================*/
				/* out: TRUE if enough free pages in list */
	ibuf_data_t*	data)	/* in: ibuf data for the space */
{
#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&ibuf_mutex));
#endif /* UNIV_SYNC_DEBUG */

	/* We want a big margin of free pages, because a B-tree can sometimes
	grow in size also if records are deleted from it, as the node pointers
	can change, and we must make sure that we are able to delete the
	inserts buffered for pages that we read to the buffer pool, without
	any risk of running out of free space in the insert buffer. */

	if (data->free_list_len >= data->size / 2 + 3 * data->height) {

		return(TRUE);
	}

	return(FALSE);
}

/*************************************************************************
Checks if there are enough pages in the free list of the ibuf tree that we
should remove them and free to the file space management. */
UNIV_INLINE
ibool
ibuf_data_too_much_free(
/*====================*/
				/* out: TRUE if enough free pages in list */
	ibuf_data_t*	data)	/* in: ibuf data for the space */
{
#ifdef UNIV_SYNC_DEBUG
	ut_ad(mutex_own(&ibuf_mutex));
#endif /* UNIV_SYNC_DEBUG */

	if (data->free_list_len >= 3 + data->size / 2 + 3 * data->height) {

		return(TRUE);
	}

	return(FALSE);
}

/*************************************************************************
Allocates a new page from the ibuf file segment and adds it to the free
list. */
static
ulint
ibuf_add_free_page(
/*===============*/
					/* out: DB_SUCCESS, or DB_STRONG_FAIL
					if no space left */
	ulint		space,		/* in: space id */
	ibuf_data_t*	ibuf_data)	/* in: ibuf data for the space */
{
	mtr_t	mtr;
	page_t*	header_page;
	ulint	page_no;
	page_t*	page;
	page_t*	root;
	page_t*	bitmap_page;

	ut_a(space == 0);

	mtr_start(&mtr);

	/* Acquire the fsp latch before the ibuf header, obeying the latching
	order */
	mtr_x_lock(fil_space_get_latch(space), &mtr);
	
	header_page = ibuf_header_page_get(space, &mtr);

	/* Allocate a new page: NOTE that if the page has been a part of a
	non-clustered index which has subsequently been dropped, then the
	page may have buffered inserts in the insert buffer, and these
	should be deleted from there. These get deleted when the page
	allocation creates the page in buffer. Thus the call below may end
	up calling the insert buffer routines and, as we yet have no latches
	to insert buffer tree pages, these routines can run without a risk
	of a deadlock. This is the reason why we created a special ibuf
	header page apart from the ibuf tree. */

	page_no = fseg_alloc_free_page(header_page + IBUF_HEADER
					+ IBUF_TREE_SEG_HEADER, 0, FSP_UP,
									&mtr);
	if (page_no == FIL_NULL) {
		mtr_commit(&mtr);

		return(DB_STRONG_FAIL);
	}

	page = buf_page_get(space, page_no, RW_X_LATCH, &mtr);

#ifdef UNIV_SYNC_DEBUG
	buf_page_dbg_add_level(page, SYNC_TREE_NODE_NEW);
#endif /* UNIV_SYNC_DEBUG */

	ibuf_enter();

	mutex_enter(&ibuf_mutex);

	root = ibuf_tree_root_get(ibuf_data, space, &mtr);

	/* Add the page to the free list and update the ibuf size data */

	flst_add_last(root + PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST,
		      page + PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST_NODE, &mtr);

	fil_page_set_type(page, FIL_PAGE_IBUF_FREE_LIST);

	ibuf_data->seg_size++;
	ibuf_data->free_list_len++;

	/* Set the bit indicating that this page is now an ibuf tree page
	(level 2 page) */

	bitmap_page = ibuf_bitmap_get_map_page(space, page_no, &mtr);

	ibuf_bitmap_page_set_bits(bitmap_page, page_no, IBUF_BITMAP_IBUF,
								TRUE, &mtr);
	mtr_commit(&mtr);

	mutex_exit(&ibuf_mutex);

	ibuf_exit();

	return(DB_SUCCESS);
}

/*************************************************************************
Removes a page from the free list and frees it to the fsp system. */
static
void
ibuf_remove_free_page(
/*==================*/
	ulint		space,		/* in: space id */
	ibuf_data_t*	ibuf_data)	/* in: ibuf data for the space */
{
	mtr_t	mtr;
	mtr_t	mtr2;
	page_t*	header_page;
	ulint	page_no;
	page_t*	page;
	page_t*	root;
	page_t*	bitmap_page;

	ut_a(space == 0);

	mtr_start(&mtr);

	/* Acquire the fsp latch before the ibuf header, obeying the latching
	order */
	mtr_x_lock(fil_space_get_latch(space), &mtr);
	
	header_page = ibuf_header_page_get(space, &mtr);

	/* Prevent pessimistic inserts to insert buffer trees for a while */
	mutex_enter(&ibuf_pessimistic_insert_mutex);

	ibuf_enter();

	mutex_enter(&ibuf_mutex);

	if (!ibuf_data_too_much_free(ibuf_data)) {

		mutex_exit(&ibuf_mutex);

		ibuf_exit();
		
		mutex_exit(&ibuf_pessimistic_insert_mutex);

		mtr_commit(&mtr);

		return;
	}
	
	mtr_start(&mtr2);
	
	root = ibuf_tree_root_get(ibuf_data, space, &mtr2);

	page_no = flst_get_last(root + PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST,
									&mtr2)
		  .page;

	/* NOTE that we must release the latch on the ibuf tree root
	because in fseg_free_page we access level 1 pages, and the root
	is a level 2 page. */
		  
	mtr_commit(&mtr2);
	mutex_exit(&ibuf_mutex);

	ibuf_exit();
	
	/* Since pessimistic inserts were prevented, we know that the
	page is still in the free list. NOTE that also deletes may take
	pages from the free list, but they take them from the start, and
	the free list was so long that they cannot have taken the last
	page from it. */
	
	fseg_free_page(header_page + IBUF_HEADER + IBUF_TREE_SEG_HEADER,
							space, page_no, &mtr);
#ifdef UNIV_DEBUG_FILE_ACCESSES
	buf_page_reset_file_page_was_freed(space, page_no);
#endif
	ibuf_enter();
							
	mutex_enter(&ibuf_mutex);

	root = ibuf_tree_root_get(ibuf_data, space, &mtr);

	ut_ad(page_no == flst_get_last(root + PAGE_HEADER
					+ PAGE_BTR_IBUF_FREE_LIST, &mtr)
		  	 .page);

	page = buf_page_get(space, page_no, RW_X_LATCH, &mtr);

#ifdef UNIV_SYNC_DEBUG
	buf_page_dbg_add_level(page, SYNC_TREE_NODE);
#endif /* UNIV_SYNC_DEBUG */

	/* Remove the page from the free list and update the ibuf size data */
	
	flst_remove(root + PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST,
		    page + PAGE_HEADER + PAGE_BTR_IBUF_FREE_LIST_NODE, &mtr);

	ibuf_data->seg_size--;
	ibuf_data->free_list_len--;
		      
	mutex_exit(&ibuf_pessimistic_insert_mutex);

	/* Set the bit indicating that this page is no more an ibuf tree page
	(level 2 page) */

	bitmap_page = ibuf_bitmap_get_map_page(space, page_no, &mtr);

	ibuf_bitmap_page_set_bits(bitmap_page, page_no, IBUF_BITMAP_IBUF,
								FALSE, &mtr);
#ifdef UNIV_DEBUG_FILE_ACCESSES
	buf_page_set_file_page_was_freed(space, page_no);
#endif
	mtr_commit(&mtr);

	mutex_exit(&ibuf_mutex);

	ibuf_exit();
}

/***************************************************************************
Frees excess pages from the ibuf free list. This function is called when an OS
thread calls fsp services to allocate a new file segment, or a new page to a
file segment, and the thread did not own the fsp latch before this call. */ 

void
ibuf_free_excess_pages(
/*===================*/
	ulint	space)	/* in: space id */
{
	ibuf_data_t*	ibuf_data;
	ulint		i;

	if (space != 0) {
	        fprintf(stderr,
"InnoDB: Error: calling ibuf_free_excess_pages for space %lu\n", (ulong) space);
		return;
	}

#ifdef UNIV_SYNC_DEBUG
	ut_ad(rw_lock_own(fil_space_get_latch(space), RW_LOCK_EX));
#endif /* UNIV_SYNC_DEBUG */
	ut_ad(rw_lock_get_x_lock_count(fil_space_get_latch(space)) == 1);
	ut_ad(!ibuf_inside());
	
	/* NOTE: We require that the thread did not own the latch before,
	because then we know that we can obey the correct latching order
	for ibuf latches */

	ibuf_data = fil_space_get_ibuf_data(space);

	if (ibuf_data == NULL) {
		/* Not yet initialized */

#ifdef UNIV_DEBUG
		/*fprintf(stderr,
			"Ibuf for space %lu not yet initialized\n", space); */
#endif

		return;
	}

	/* Free at most a few pages at a time, so that we do not delay the
	requested service too much */

	for (i = 0; i < 4; i++) {

		mutex_enter(&ibuf_mutex);

		if (!ibuf_data_too_much_free(ibuf_data)) {

			mutex_exit(&ibuf_mutex);

			return;
		}

		mutex_exit(&ibuf_mutex);

		ibuf_remove_free_page(space, ibuf_data);
	}
}

/*************************************************************************
Reads page numbers from a leaf in an ibuf tree. */
static
ulint
ibuf_get_merge_page_nos(
/*====================*/
				/* out: a lower limit for the combined volume
				of records which will be merged */
	ibool		contract,/* in: TRUE if this function is called to
				contract the tree, FALSE if this is called
				when a single page becomes full and we look
				if it pays to read also nearby pages */
	rec_t*		rec,	/* in: record from which we read up and down
				in the chain of records */
	ulint*		space_ids,/* in/out: space id's of the pages */
	ib_longlong*	space_versions,/* in/out: tablespace version
				timestamps; used to prevent reading in old
				pages after DISCARD + IMPORT tablespace */
	ulint*		page_nos,/* in/out: buffer for at least
				IBUF_MAX_N_PAGES_MERGED many page numbers;
				the page numbers are in an ascending order */
	ulint*		n_stored)/* out: number of page numbers stored to
				page_nos in this function */
{
	ulint	prev_page_no;
	ulint	prev_space_id;
	ulint	first_page_no;
	ulint	first_space_id;
	ulint	rec_page_no;
	ulint	rec_space_id;
	ulint	sum_volumes;
	ulint	volume_for_page;
	ulint	rec_volume;
	ulint	limit;
	ulint	n_pages;

	*n_stored = 0;

	limit = ut_min(IBUF_MAX_N_PAGES_MERGED, buf_pool->curr_size / 4);

	if (page_rec_is_supremum(rec)) {

		rec = page_rec_get_prev(rec);
	}

	if (page_rec_is_infimum(rec)) {

		rec = page_rec_get_next(rec);
	}

	if (page_rec_is_supremum(rec)) {

		return(0);
	}

	first_page_no = ibuf_rec_get_page_no(rec);
	first_space_id = ibuf_rec_get_space(rec);
	n_pages = 0;
	prev_page_no = 0;
	prev_space_id = 0;
	
	/* Go backwards from the first rec until we reach the border of the
	'merge area', or the page start or the limit of storeable pages is
	reached */

	while (!page_rec_is_infimum(rec) && UNIV_LIKELY(n_pages < limit)) {

		rec_page_no = ibuf_rec_get_page_no(rec);
		rec_space_id = ibuf_rec_get_space(rec);

		if (rec_space_id != first_space_id
		    || rec_page_no / IBUF_MERGE_AREA
		       != first_page_no / IBUF_MERGE_AREA) {

		    	break;
		}
		
		if (rec_page_no != prev_page_no
		    || rec_space_id != prev_space_id) {
			n_pages++;
		}

		prev_page_no = rec_page_no;
		prev_space_id = rec_space_id;

		rec = page_rec_get_prev(rec);
	}

	rec = page_rec_get_next(rec);

	/* At the loop start there is no prev page; we mark this with a pair
	of space id, page no (0, 0) for which there can never be entries in
	the insert buffer */

	prev_page_no = 0;
	prev_space_id = 0;
	sum_volumes = 0;
	volume_for_page = 0;
	
	while (*n_stored < limit) {
		if (page_rec_is_supremum(rec)) {
			/* When no more records available, mark this with
			another 'impossible' pair of space id, page no */
			rec_page_no = 1;
			rec_space_id = 0;
		} else {
			rec_page_no = ibuf_rec_get_page_no(rec);
			rec_space_id = ibuf_rec_get_space(rec);
			ut_ad(rec_page_no > IBUF_TREE_ROOT_PAGE_NO);
		}

#ifdef UNIV_IBUF_DEBUG
		ut_a(*n_stored < IBUF_MAX_N_PAGES_MERGED);
#endif
		if ((rec_space_id != prev_space_id
		     || rec_page_no != prev_page_no)
                    && (prev_space_id != 0 || prev_page_no != 0)) {

			if ((prev_page_no == first_page_no
			     && prev_space_id == first_space_id)
			    || contract
			    || (volume_for_page >
			     ((IBUF_MERGE_THRESHOLD - 1)
			      * 4 * UNIV_PAGE_SIZE
				    / IBUF_PAGE_SIZE_PER_FREE_SPACE)