btr0btr.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

			/* Ok, there will be enough available space on the
			half page where the tuple is inserted */

			return(TRUE);
		}

		rec = page_rec_get_next(rec);
	}

	return(FALSE);
}		

/***********************************************************
Inserts a data tuple to a tree on a non-leaf level. It is assumed
that mtr holds an x-latch on the tree. */

void
btr_insert_on_non_leaf_level(
/*=========================*/
	dict_tree_t*	tree,	/* in: tree */
	ulint		level,	/* in: level, must be > 0 */
	dtuple_t*	tuple,	/* in: the record to be inserted */
	mtr_t*		mtr)	/* in: mtr */
{
	big_rec_t*	dummy_big_rec;
	btr_cur_t	cursor;		
	ulint		err;
	rec_t*		rec;

	ut_ad(level > 0);
	
	/* In the following, choose just any index from the tree as the
	first parameter for btr_cur_search_to_nth_level. */

	btr_cur_search_to_nth_level(UT_LIST_GET_FIRST(tree->tree_indexes),
				    level, tuple, PAGE_CUR_LE,
				    BTR_CONT_MODIFY_TREE,
				    &cursor, 0, mtr);

	err = btr_cur_pessimistic_insert(BTR_NO_LOCKING_FLAG
					| BTR_KEEP_SYS_FLAG
					| BTR_NO_UNDO_LOG_FLAG,
					&cursor, tuple,
					&rec, &dummy_big_rec, NULL, mtr);
	ut_a(err == DB_SUCCESS);
}

/******************************************************************
Attaches the halves of an index page on the appropriate level in an
index tree. */
static
void
btr_attach_half_pages(
/*==================*/
	dict_tree_t*	tree,		/* in: the index tree */
	page_t*		page,		/* in: page to be split */
	rec_t*		split_rec,	/* in: first record on upper
					half page */
	page_t*		new_page,	/* in: the new half page */
	ulint		direction,	/* in: FSP_UP or FSP_DOWN */
	mtr_t*		mtr)		/* in: mtr */
{
	ulint		space;
	rec_t*		node_ptr;
	page_t*		prev_page;
	page_t*		next_page;
	ulint		prev_page_no;
	ulint		next_page_no;
	ulint		level;
	page_t*		lower_page;
	page_t*		upper_page;
	ulint		lower_page_no;
	ulint		upper_page_no;
	dtuple_t*	node_ptr_upper;
	mem_heap_t* 	heap;

	ut_ad(mtr_memo_contains(mtr, buf_block_align(page),
			      				MTR_MEMO_PAGE_X_FIX));
	ut_ad(mtr_memo_contains(mtr, buf_block_align(new_page),
			      				MTR_MEMO_PAGE_X_FIX));
	ut_a(page_is_comp(page) == page_is_comp(new_page));

	/* Create a memory heap where the data tuple is stored */
	heap = mem_heap_create(1024);

	/* Based on split direction, decide upper and lower pages */
	if (direction == FSP_DOWN) {

		lower_page_no = buf_frame_get_page_no(new_page);
		upper_page_no = buf_frame_get_page_no(page);
		lower_page = new_page;
		upper_page = page;

		/* Look from the tree for the node pointer to page */
		node_ptr = btr_page_get_father_node_ptr(tree, page, mtr);

		/* Replace the address of the old child node (= page) with the 
		address of the new lower half */

		btr_node_ptr_set_child_page_no(node_ptr,
			rec_get_offsets(node_ptr,
					UT_LIST_GET_FIRST(tree->tree_indexes),
					NULL, ULINT_UNDEFINED, &heap),
			lower_page_no, mtr);
		mem_heap_empty(heap);
	} else {
		lower_page_no = buf_frame_get_page_no(page);
		upper_page_no = buf_frame_get_page_no(new_page);
		lower_page = page;
		upper_page = new_page;
	}
				   
	/* Get the level of the split pages */
	level = btr_page_get_level(page, mtr);

	/* Build the node pointer (= node key and page address) for the upper
	half */

	node_ptr_upper = dict_tree_build_node_ptr(tree, split_rec,
					     upper_page_no, heap, level);

	/* Insert it next to the pointer to the lower half. Note that this
	may generate recursion leading to a split on the higher level. */

	btr_insert_on_non_leaf_level(tree, level + 1, node_ptr_upper, mtr);
		
	/* Free the memory heap */
	mem_heap_free(heap);

	/* Get the previous and next pages of page */

	prev_page_no = btr_page_get_prev(page, mtr);
	next_page_no = btr_page_get_next(page, mtr);
	space = buf_frame_get_space_id(page);
	
	/* Update page links of the level */
	
	if (prev_page_no != FIL_NULL) {

		prev_page = btr_page_get(space, prev_page_no, RW_X_LATCH, mtr);
		ut_a(page_is_comp(prev_page) == page_is_comp(page));

		btr_page_set_next(prev_page, lower_page_no, mtr);
	}

	if (next_page_no != FIL_NULL) {

		next_page = btr_page_get(space, next_page_no, RW_X_LATCH, mtr);
		ut_a(page_is_comp(next_page) == page_is_comp(page));

		btr_page_set_prev(next_page, upper_page_no, mtr);
	}
	
	btr_page_set_prev(lower_page, prev_page_no, mtr);
	btr_page_set_next(lower_page, upper_page_no, mtr);
	btr_page_set_level(lower_page, level, mtr);

	btr_page_set_prev(upper_page, lower_page_no, mtr);
	btr_page_set_next(upper_page, next_page_no, mtr);
	btr_page_set_level(upper_page, level, mtr);
}

/*****************************************************************
Splits an index page to halves and inserts the tuple. It is assumed
that mtr holds an x-latch to the index tree. NOTE: the tree x-latch
is released within this function! NOTE that the operation of this
function must always succeed, we cannot reverse it: therefore
enough free disk space must be guaranteed to be available before
this function is called. */

rec_t*
btr_page_split_and_insert(
/*======================*/
				/* out: inserted record; NOTE: the tree
				x-latch is released! NOTE: 2 free disk
				pages must be available! */
	btr_cur_t*	cursor,	/* in: cursor at which to insert; when the
				function returns, the cursor is positioned
				on the predecessor of the inserted record */
	dtuple_t*	tuple,	/* in: tuple to insert */
	mtr_t*		mtr)	/* in: mtr */
{
	dict_tree_t*	tree;
	page_t*		page;
	ulint		page_no;
	byte		direction;
	ulint		hint_page_no;
	page_t*		new_page;
	rec_t*		split_rec;
	page_t*		left_page;
	page_t*		right_page;
	page_t*		insert_page;
	page_cur_t*	page_cursor;
	rec_t*		first_rec;
	byte*		buf = 0; /* remove warning */
	rec_t*		move_limit;
	ibool		insert_will_fit;
	ulint		n_iterations = 0;
	rec_t*		rec;
	mem_heap_t*	heap;
	ulint		n_uniq;
	ulint*		offsets;

	heap = mem_heap_create(1024);
	n_uniq = dict_index_get_n_unique_in_tree(cursor->index);
func_start:
	mem_heap_empty(heap);
	offsets = NULL;
	tree = btr_cur_get_tree(cursor);
	
	ut_ad(mtr_memo_contains(mtr, dict_tree_get_lock(tree),
							MTR_MEMO_X_LOCK));
#ifdef UNIV_SYNC_DEBUG
	ut_ad(rw_lock_own(dict_tree_get_lock(tree), RW_LOCK_EX));
#endif /* UNIV_SYNC_DEBUG */

	page = btr_cur_get_page(cursor);

	ut_ad(mtr_memo_contains(mtr, buf_block_align(page),
			      				MTR_MEMO_PAGE_X_FIX));
	ut_ad(page_get_n_recs(page) >= 2);
	
	page_no = buf_frame_get_page_no(page);

	/* 1. Decide the split record; split_rec == NULL means that the
	tuple to be inserted should be the first record on the upper
	half-page */

	if (n_iterations > 0) {
		direction = FSP_UP;
		hint_page_no = page_no + 1;
		split_rec = btr_page_get_sure_split_rec(cursor, tuple);
		
	} else if (btr_page_get_split_rec_to_right(cursor, &split_rec)) {
		direction = FSP_UP;
		hint_page_no = page_no + 1;

	} else if (btr_page_get_split_rec_to_left(cursor, &split_rec)) {
		direction = FSP_DOWN;
		hint_page_no = page_no - 1;
	} else {
		direction = FSP_UP;
		hint_page_no = page_no + 1;
		split_rec = page_get_middle_rec(page);
	}

	/* 2. Allocate a new page to the tree */
	new_page = btr_page_alloc(tree, hint_page_no, direction,
					btr_page_get_level(page, mtr), mtr);
	btr_page_create(new_page, tree, mtr);
	
	/* 3. Calculate the first record on the upper half-page, and the
	first record (move_limit) on original page which ends up on the
	upper half */

	if (split_rec != NULL) {
		first_rec = split_rec;
		move_limit = split_rec;
	} else {
		buf = mem_alloc(rec_get_converted_size(cursor->index, tuple));

		first_rec = rec_convert_dtuple_to_rec(buf,
							cursor->index, tuple);
		move_limit = page_rec_get_next(btr_cur_get_rec(cursor));
	}
	
	/* 4. Do first the modifications in the tree structure */

	btr_attach_half_pages(tree, page, first_rec, new_page, direction, mtr);

	if (split_rec == NULL) {
		mem_free(buf);
	}

	/* If the split is made on the leaf level and the insert will fit
	on the appropriate half-page, we may release the tree x-latch.
	We can then move the records after releasing the tree latch,
	thus reducing the tree latch contention. */

	if (split_rec) {
		offsets = rec_get_offsets(split_rec, cursor->index, offsets,
							n_uniq, &heap);

		insert_will_fit = btr_page_insert_fits(cursor,
					split_rec, offsets, tuple, heap);
	} else {
		insert_will_fit = btr_page_insert_fits(cursor,
					NULL, NULL, tuple, heap);
	}
	
	if (insert_will_fit && (btr_page_get_level(page, mtr) == 0)) {

		mtr_memo_release(mtr, dict_tree_get_lock(tree),
							MTR_MEMO_X_LOCK);
	}

	/* 5. Move then the records to the new page */
	if (direction == FSP_DOWN) {
/*		fputs("Split left\n", stderr); */

		page_move_rec_list_start(new_page, page, move_limit,
							cursor->index, mtr);
		left_page = new_page;
		right_page = page;

		lock_update_split_left(right_page, left_page);
	} else {
/*		fputs("Split right\n", stderr); */

		page_move_rec_list_end(new_page, page, move_limit,
							cursor->index, mtr);
		left_page = page;
		right_page = new_page;

		lock_update_split_right(right_page, left_page);
	}

	/* 6. The split and the tree modification is now completed. Decide the
	page where the tuple should be inserted */

	if (split_rec == NULL) {
		insert_page = right_page;

	} else {
		offsets = rec_get_offsets(first_rec, cursor->index,
						offsets, n_uniq, &heap);

		if (cmp_dtuple_rec(tuple, first_rec, offsets) >= 0) {

			insert_page = right_page;
		} else {
			insert_page = left_page;
		}
	}

	/* 7. Reposition the cursor for insert and try insertion */
	page_cursor = btr_cur_get_page_cur(cursor);

	page_cur_search(insert_page, cursor->index, tuple,
						PAGE_CUR_LE, page_cursor);

	rec = page_cur_tuple_insert(page_cursor, tuple, cursor->index, mtr);

	if (rec != NULL) {
		/* Insert fit on the page: update the free bits for the
		left and right pages in the same mtr */

		ibuf_update_free_bits_for_two_pages_low(cursor->index,
							left_page,
							right_page, mtr);
		/* fprintf(stderr, "Split and insert done %lu %lu\n",
				buf_frame_get_page_no(left_page),
				buf_frame_get_page_no(right_page)); */
		mem_heap_free(heap);
		return(rec);
	}
	
	/* 8. If insert did not fit, try page reorganization */

	btr_page_reorganize(insert_page, cursor->index, mtr);

	page_cur_search(insert_page, cursor->index, tuple,
						PAGE_CUR_LE, page_cursor);
	rec = page_cur_tuple_insert(page_cursor, tuple, cursor->index, mtr);

	if (rec == NULL) {
		/* The insert did not fit on the page: loop back to the
		start of the function for a new split */
		
		/* We play safe and reset the free bits for new_page */
		ibuf_reset_free_bits(cursor->index, new_page);

		/* fprintf(stderr, "Split second round %lu\n",
					buf_frame_get_page_no(page)); */
		n_iterations++;
		ut_ad(n_iterations < 2);
		ut_ad(!insert_will_fit);

		goto func_start;
	}

	/* Insert fit on the page: update the free bits for the
	left and right pages in the same mtr */

	ibuf_update_free_bits_for_two_pages_low(cursor->index, left_page,
							right_page, mtr);
	/* fprintf(stderr, "Split and insert done %lu %lu\n",
				buf_frame_get_page_no(left_page),
				buf_frame_get_page_no(right_page)); */

	ut_ad(page_validate(left_page, UT_LIST_GET_FIRST(tree->tree_indexes)));
	ut_ad(page_validate(right_page, UT_LIST_GET_FIRST(tree->tree_indexes)));

	mem_heap_free(heap);
	return(rec);
}

/*****************************************************************
Removes a page from the level list of pages. */
static
void
btr_level_list_remove(
/*==================*/
	dict_tree_t*	tree __attribute__((unused)), /* in: index tree */
	page_t*		page,	/* in: page to remove */
	mtr_t*		mtr)	/* in: mtr */
{	
	ulint	space;
	ulint	prev_page_no;
	page_t*	prev_page;
	ulint	next_page_no;
	page_t*	next_page;
	
	ut_ad(tree && page && mtr);
	ut_ad(mtr_memo_contains(mtr, buf_block_align(page),
			      				MTR_MEMO_PAGE_X_FIX));
	/* Get the previous and next page numbers of page */

	prev_page_no = btr_page_get_prev(page, mtr);
	next_page_no = btr_page_get_next(page, mtr);
	space = buf_frame_get_space_id(page);
	
	/* Update page links of the level */
	
	if (prev_page_no != FIL_NULL) {

		prev_page = btr_page_get(space, prev_page_no, RW_X_LATCH, mtr);
		ut_a(page_is_comp(prev_page) == page_is_comp(page));

		btr_page_set_next(prev_page, next_page_no, mtr);
	}

	if (next_page_no != FIL_NULL) {

		next_page = btr_page_get(space, next_page_no, RW_X_LATCH, mtr);
		ut_a(page_is_comp(next_page) == page_is_comp(page));

		btr_page_set_prev(next_page, prev_page_no, mtr);
	}
}
	
/********************************************************************
Writes the redo log record for setting an index record as the predefined
minimum record. */
UNIV_INLINE
void
btr_set_min_rec_mark_log(
/*=====================*/
	rec_t*	rec,	/* in: record */
	ulint	comp,	/* nonzero=compact record format */
	mtr_t*	mtr)	/* in: mtr */
{
	mlog_write_initial_log_record(rec,
		comp ? MLOG_COMP_REC_MIN_MARK : MLOG_REC_MIN_MARK, mtr);

	/* Write rec offset as a 2-byte ulint */
	mlog_catenate_ulint(mtr, ut_align_offset(rec, UNIV_PAGE_SIZE),
								MLOG_2BYTES);
}

/********************************************************************