btr0sea.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

	bytes = 0;

	offsets = rec_get_offsets(rec, cursor->index, offsets,
						n_unique, &heap);
	cmp = page_cmp_dtuple_rec_with_match(tuple, rec,
						offsets, &match, &bytes);

	if (mode == PAGE_CUR_GE) {
		if (cmp == 1) {
			goto exit_func;
		}

		cursor->up_match = match;

		if (match >= n_unique) {
			success = TRUE;
			goto exit_func;
		}	
	} else if (mode == PAGE_CUR_LE) {
		if (cmp == -1) {
			goto exit_func;
		}

		cursor->low_match = match;

	} else if (mode == PAGE_CUR_G) {
		if (cmp != -1) {
			goto exit_func;
		}
	} else if (mode == PAGE_CUR_L) {
		if (cmp != 1) {
			goto exit_func;
		}
	}

	if (can_only_compare_to_cursor_rec) {
	        /* Since we could not determine if our guess is right just by
	        looking at the record under the cursor, return FALSE */
		goto exit_func;
	}

	match = 0;
	bytes = 0;

	if ((mode == PAGE_CUR_G) || (mode == PAGE_CUR_GE)) {
		rec_t*	prev_rec;

		ut_ad(!page_rec_is_infimum(rec));
		
		prev_rec = page_rec_get_prev(rec);

		if (page_rec_is_infimum(prev_rec)) {
			success = btr_page_get_prev(
				buf_frame_align(prev_rec), mtr) == FIL_NULL;

			goto exit_func;
		}

		offsets = rec_get_offsets(prev_rec, cursor->index, offsets,
						n_unique, &heap);
		cmp = page_cmp_dtuple_rec_with_match(tuple, prev_rec,
					offsets, &match, &bytes);
		if (mode == PAGE_CUR_GE) {
			success = cmp == 1;
		} else {
			success = cmp != -1;
		}

		goto exit_func;
	} else {
		rec_t*	next_rec;

		ut_ad(!page_rec_is_supremum(rec));
	
		next_rec = page_rec_get_next(rec);

		if (page_rec_is_supremum(next_rec)) {
			if (btr_page_get_next(
				buf_frame_align(next_rec), mtr) == FIL_NULL) {

				cursor->up_match = 0;
				success = TRUE;
			}

			goto exit_func;
		}

		offsets = rec_get_offsets(next_rec, cursor->index, offsets,
						n_unique, &heap);
		cmp = page_cmp_dtuple_rec_with_match(tuple, next_rec,
						offsets, &match, &bytes);
		if (mode == PAGE_CUR_LE) {
			success = cmp == -1;
			cursor->up_match = match;
		} else {
			success = cmp != 1;
		}
	}
exit_func:
	if (UNIV_LIKELY_NULL(heap)) {
		mem_heap_free(heap);
	}
	return(success);
}

/**********************************************************************
Tries to guess the right search position based on the hash search info
of the index. Note that if mode is PAGE_CUR_LE, which is used in inserts,
and the function returns TRUE, then cursor->up_match and cursor->low_match
both have sensible values. */

ibool
btr_search_guess_on_hash(
/*=====================*/
					/* out: TRUE if succeeded */	
	dict_index_t*	index,		/* in: index */
	btr_search_t*	info,		/* in: index search info */
	dtuple_t*	tuple,		/* in: logical record */
	ulint		mode,		/* in: PAGE_CUR_L, ... */
	ulint		latch_mode, 	/* in: BTR_SEARCH_LEAF, ...;
					NOTE that only if has_search_latch
					is 0, we will have a latch set on
					the cursor page, otherwise we assume
					the caller uses his search latch
					to protect the record! */
	btr_cur_t*	cursor, 	/* out: tree cursor */
	ulint		has_search_latch,/* in: latch mode the caller
					currently has on btr_search_latch:
					RW_S_LATCH, RW_X_LATCH, or 0 */
	mtr_t*		mtr)		/* in: mtr */
{
	buf_block_t*	block;
	rec_t*		rec;
	page_t*		page;
	ulint		fold;
	ulint		tuple_n_fields;
	dulint		tree_id;
	ibool           can_only_compare_to_cursor_rec = TRUE;
#ifdef notdefined
	btr_cur_t	cursor2;
	btr_pcur_t	pcur;
#endif
	ut_ad(index && info && tuple && cursor && mtr);
	ut_ad((latch_mode == BTR_SEARCH_LEAF)
					|| (latch_mode == BTR_MODIFY_LEAF));

	/* Note that, for efficiency, the struct info may not be protected by
	any latch here! */

	if (UNIV_UNLIKELY(info->n_hash_potential == 0)) {

		return(FALSE);
	}

	cursor->n_fields = info->n_fields;
	cursor->n_bytes = info->n_bytes;

	tuple_n_fields = dtuple_get_n_fields(tuple);

	if (UNIV_UNLIKELY(tuple_n_fields < cursor->n_fields)) {

		return(FALSE);
	}

	if (UNIV_UNLIKELY(tuple_n_fields == cursor->n_fields)
			&& (cursor->n_bytes > 0)) {

	    	return(FALSE);
	}

	tree_id = (index->tree)->id;

#ifdef UNIV_SEARCH_PERF_STAT
	info->n_hash_succ++;
#endif
	fold = dtuple_fold(tuple, cursor->n_fields, cursor->n_bytes, tree_id);

	cursor->fold = fold;
	cursor->flag = BTR_CUR_HASH;
	
	if (UNIV_LIKELY(!has_search_latch)) {
		rw_lock_s_lock(&btr_search_latch);
	}

	ut_ad(btr_search_latch.writer != RW_LOCK_EX);
	ut_ad(btr_search_latch.reader_count > 0);

	rec = ha_search_and_get_data(btr_search_sys->hash_index, fold);

	if (UNIV_UNLIKELY(!rec)) {
		goto failure_unlock;
	}

	page = buf_frame_align(rec);

	if (UNIV_LIKELY(!has_search_latch)) {

		if (UNIV_UNLIKELY(!buf_page_get_known_nowait(latch_mode, page,
						BUF_MAKE_YOUNG,
						__FILE__, __LINE__,
						mtr))) {
			goto failure_unlock;
		}

		rw_lock_s_unlock(&btr_search_latch);
		can_only_compare_to_cursor_rec = FALSE;

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

	block = buf_block_align(page);

	if (UNIV_UNLIKELY(block->state == BUF_BLOCK_REMOVE_HASH)) {
		if (UNIV_LIKELY(!has_search_latch)) {
	
			btr_leaf_page_release(page, latch_mode, mtr);
		}

		goto failure;
	}

	ut_ad(block->state == BUF_BLOCK_FILE_PAGE);
	ut_ad(page_rec_is_user_rec(rec));

	btr_cur_position(index, rec, cursor);

	/* Check the validity of the guess within the page */

	/* If we only have the latch on btr_search_latch, not on the
	page, it only protects the columns of the record the cursor
	is positioned on. We cannot look at the next of the previous
	record to determine if our guess for the cursor position is
	right. */
	if (UNIV_EXPECT(ut_dulint_cmp(tree_id, btr_page_get_index_id(page)), 0)
	    || !btr_search_check_guess(cursor, can_only_compare_to_cursor_rec,
					       tuple, mode, mtr)) {
		if (UNIV_LIKELY(!has_search_latch)) {
		          btr_leaf_page_release(page, latch_mode, mtr);
		}

		goto failure;
	}

	if (UNIV_LIKELY(info->n_hash_potential < BTR_SEARCH_BUILD_LIMIT + 5)) {
	
		info->n_hash_potential++;
	}

#ifdef notdefined
	/* These lines of code can be used in a debug version to check
	the correctness of the searched cursor position: */
	
	info->last_hash_succ = FALSE;

	/* Currently, does not work if the following fails: */
	ut_ad(!has_search_latch);
	
	btr_leaf_page_release(page, latch_mode, mtr);

	btr_cur_search_to_nth_level(index, 0, tuple, mode, latch_mode,
							&cursor2, 0, mtr);
	if (mode == PAGE_CUR_GE
		&& page_rec_is_supremum(btr_cur_get_rec(&cursor2))) {

		/* If mode is PAGE_CUR_GE, then the binary search
		in the index tree may actually take us to the supremum
		of the previous page */
					
		info->last_hash_succ = FALSE;

		btr_pcur_open_on_user_rec(index, tuple, mode, latch_mode,
				&pcur, mtr);
		ut_ad(btr_pcur_get_rec(&pcur) == btr_cur_get_rec(cursor));
	} else {
		ut_ad(btr_cur_get_rec(&cursor2) == btr_cur_get_rec(cursor));
	}

	/* NOTE that it is theoretically possible that the above assertions
	fail if the page of the cursor gets removed from the buffer pool
	meanwhile! Thus it might not be a bug. */
#endif
	info->last_hash_succ = TRUE;

#ifdef UNIV_SEARCH_PERF_STAT
	btr_search_n_succ++;
#endif
	if (UNIV_LIKELY(!has_search_latch)
			&& buf_block_peek_if_too_old(block)) {

		buf_page_make_young(page);
	}	

	/* Increment the page get statistics though we did not really
	fix the page: for user info only */

	buf_pool->n_page_gets++;

	return(TRUE);	

	/*-------------------------------------------*/
failure_unlock:
	if (UNIV_LIKELY(!has_search_latch)) {
		rw_lock_s_unlock(&btr_search_latch);
	}
failure:
	info->n_hash_fail++;

	cursor->flag = BTR_CUR_HASH_FAIL;

#ifdef UNIV_SEARCH_PERF_STAT
	if (info->n_hash_succ > 0) {
		info->n_hash_succ--;
	}
#endif
	info->last_hash_succ = FALSE;

	return(FALSE);
}

/************************************************************************
Drops a page hash index. */

void
btr_search_drop_page_hash_index(
/*============================*/
	page_t*	page)	/* in: index page, s- or x-latched, or an index page
			for which we know that block->buf_fix_count == 0 */
{
	hash_table_t*	table;
	buf_block_t*	block;
	ulint		n_fields;
	ulint		n_bytes;
	rec_t*		rec;
	ulint		fold;
	ulint		prev_fold;
	dulint		tree_id;
	ulint		n_cached;
	ulint		n_recs;
	ulint*		folds;
	ulint		i;
	mem_heap_t*	heap;
	dict_index_t*	index;
	ulint*		offsets;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(!rw_lock_own(&btr_search_latch, RW_LOCK_SHARED));
	ut_ad(!rw_lock_own(&btr_search_latch, RW_LOCK_EX));
#endif /* UNIV_SYNC_DEBUG */
retry:
	rw_lock_s_lock(&btr_search_latch);

	block = buf_block_align(page);

	if (UNIV_LIKELY(!block->is_hashed)) {

		rw_lock_s_unlock(&btr_search_latch);

		return;
	}

	table = btr_search_sys->hash_index;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(rw_lock_own(&(block->lock), RW_LOCK_SHARED)
	      			|| rw_lock_own(&(block->lock), RW_LOCK_EX)
	      			|| (block->buf_fix_count == 0));
#endif /* UNIV_SYNC_DEBUG */

	n_fields = block->curr_n_fields;
	n_bytes = block->curr_n_bytes;
	index = block->index;

	/* NOTE: The fields of block must not be accessed after
	releasing btr_search_latch, as the index page might only
	be s-latched! */

	rw_lock_s_unlock(&btr_search_latch);
	
	ut_a(n_fields + n_bytes > 0);

	n_recs = page_get_n_recs(page);

	/* Calculate and cache fold values into an array for fast deletion
	from the hash index */

	folds = mem_alloc(n_recs * sizeof(ulint));

	n_cached = 0;

	rec = page_get_infimum_rec(page);
	rec = page_rec_get_next(rec);

	tree_id = btr_page_get_index_id(page);
	
	ut_a(0 == ut_dulint_cmp(tree_id, index->id));

	prev_fold = 0;

	heap = NULL;
	offsets = NULL;

	while (!page_rec_is_supremum(rec)) {
		/* FIXME: in a mixed tree, not all records may have enough
		ordering fields: */
		offsets = rec_get_offsets(rec, index, offsets,
					n_fields + (n_bytes > 0), &heap);
		ut_a(rec_offs_n_fields(offsets) == n_fields + (n_bytes > 0));
		fold = rec_fold(rec, offsets, n_fields, n_bytes, tree_id);

		if (fold == prev_fold && prev_fold != 0) {

			goto next_rec;
		}

		/* Remove all hash nodes pointing to this page from the
		hash chain */

		folds[n_cached] = fold;
		n_cached++;
next_rec:
		rec = page_rec_get_next(rec);
		prev_fold = fold;
	}

	if (UNIV_LIKELY_NULL(heap)) {
		mem_heap_free(heap);
	}

	rw_lock_x_lock(&btr_search_latch);

	if (UNIV_UNLIKELY(!block->is_hashed)) {
		/* Someone else has meanwhile dropped the hash index */

		goto cleanup;
	}

	ut_a(block->index == index);

	if (UNIV_UNLIKELY(block->curr_n_fields != n_fields)
	    || UNIV_UNLIKELY(block->curr_n_bytes != n_bytes)) {

		/* Someone else has meanwhile built a new hash index on the
		page, with different parameters */

		rw_lock_x_unlock(&btr_search_latch);

		mem_free(folds);
		goto retry;
	}

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

		ha_remove_all_nodes_to_page(table, folds[i], page);
	}

	block->is_hashed = FALSE;
	block->index = NULL;
cleanup:
	if (UNIV_UNLIKELY(block->n_pointers)) {
		/* Corruption */
		ut_print_timestamp(stderr);
		fprintf(stderr,
"  InnoDB: Corruption of adaptive hash index. After dropping\n"
"InnoDB: the hash index to a page of %s, still %lu hash nodes remain.\n",
			index->name, (ulong) block->n_pointers);
		rw_lock_x_unlock(&btr_search_latch);

		btr_search_validate();
	} else {
		rw_lock_x_unlock(&btr_search_latch);
	}

	mem_free(folds);
}

/************************************************************************
Drops a page hash index when a page is freed from a fseg to the file system.
Drops possible hash index if the page happens to be in the buffer pool. */

void
btr_search_drop_page_hash_when_freed(
/*=================================*/
	ulint	space,		/* in: space id */
	ulint	page_no)	/* in: page number */
{
	ibool	is_hashed;
	page_t*	page;
	mtr_t	mtr;

	is_hashed = buf_page_peek_if_search_hashed(space, page_no);

	if (!is_hashed) {

		return;
	}
	
	mtr_start(&mtr);

	/* We assume that if the caller has a latch on the page, then the
	caller has already dropped the hash index for the page, and we never
	get here. Therefore we can acquire the s-latch to the page without
	having to fear a deadlock. */
	
	page = buf_page_get_gen(space, page_no, RW_S_LATCH, NULL,
				BUF_GET_IF_IN_POOL, __FILE__, __LINE__,
				&mtr);

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

	btr_search_drop_page_hash_index(page);

	mtr_commit(&mtr);
}

/************************************************************************
Builds a hash index on a page with the given parameters. If the page already
has a hash index with different parameters, the old hash index is removed.
If index is non-NULL, this function checks if n_fields and n_bytes are
sensible values, and does not build a hash index if not. */
static
void
btr_search_build_page_hash_index(
/*=============================*/
	dict_index_t*	index,	/* in: index for which to build */
	page_t*		page,	/* in: index page, s- or x-latched */
	ulint		n_fields,/* in: hash this many full fields */
	ulint		n_bytes,/* in: hash this many bytes from the next
				field */
	ulint		side)	/* in: hash for searches from this side */
{
	hash_table_t*	table;
	buf_block_t*	block;
	rec_t*		rec;
	rec_t*		next_rec;
	ulint		fold;
	ulint		next_fold;
	dulint		tree_id;
	ulint		n_cached;
	ulint		n_recs;
	ulint*		folds;
	rec_t**		recs;
	ulint		i;
	mem_heap_t*	heap		= NULL;
	ulint		offsets_[REC_OFFS_NORMAL_SIZE];
	ulint*		offsets		= offsets_;
	*offsets_ = (sizeof offsets_) / sizeof *offsets_;

	ut_ad(index);

	block = buf_block_align(page);
	table = btr_search_sys->hash_index;

#ifdef UNIV_SYNC_DEBUG
	ut_ad(!rw_lock_own(&btr_search_latch, RW_LOCK_EX));
	ut_ad(rw_lock_own(&(block->lock), RW_LOCK_SHARED)
				|| rw_lock_own(&(block->lock), RW_LOCK_EX));
#endif /* UNIV_SYNC_DEBUG */

	rw_lock_s_lock(&btr_search_latch);
				
	if (block->is_hashed && ((block->curr_n_fields != n_fields)
	        			|| (block->curr_n_bytes != n_bytes)
	        			|| (block->curr_side != side))) {