page0cur.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

	rec_set_n_owned(insert_rec, comp, 0);
	rec_set_heap_no(insert_rec, comp, heap_no);

	/* 6. Update the last insertion info in page header */	

	last_insert = page_header_get_ptr(page, PAGE_LAST_INSERT);
	ut_ad(!last_insert || !comp
		|| rec_get_node_ptr_flag(last_insert)
		== rec_get_node_ptr_flag(insert_rec));

	if (last_insert == NULL) {
	    	page_header_set_field(page, PAGE_DIRECTION, PAGE_NO_DIRECTION);
	    	page_header_set_field(page, PAGE_N_DIRECTION, 0);

	} else if ((last_insert == current_rec)
	    && (page_header_get_field(page, PAGE_DIRECTION) != PAGE_LEFT)) {

	    	page_header_set_field(page, PAGE_DIRECTION, PAGE_RIGHT);
	    	page_header_set_field(page, PAGE_N_DIRECTION,
			page_header_get_field(page, PAGE_N_DIRECTION) + 1);

	} else if ((page_rec_get_next(insert_rec) == last_insert)
	    && (page_header_get_field(page, PAGE_DIRECTION) != PAGE_RIGHT)) {

	    	page_header_set_field(page, PAGE_DIRECTION, PAGE_LEFT);
	    	page_header_set_field(page, PAGE_N_DIRECTION,
			page_header_get_field(page, PAGE_N_DIRECTION) + 1);
	} else {
	    	page_header_set_field(page, PAGE_DIRECTION, PAGE_NO_DIRECTION);
	    	page_header_set_field(page, PAGE_N_DIRECTION, 0);
	}
	
	page_header_set_ptr(page, PAGE_LAST_INSERT, insert_rec);

	/* 7. It remains to update the owner record. */		
	
	owner_rec = page_rec_find_owner_rec(insert_rec);
	n_owned = rec_get_n_owned(owner_rec, comp);
	rec_set_n_owned(owner_rec, comp, n_owned + 1);

	/* 8. Now we have incremented the n_owned field of the owner
	record. If the number exceeds PAGE_DIR_SLOT_MAX_N_OWNED,
	we have to split the corresponding directory slot in two. */

	if (n_owned == PAGE_DIR_SLOT_MAX_N_OWNED) {
		owner_slot = page_dir_find_owner_slot(owner_rec);
		page_dir_split_slot(page, owner_slot);
	}

	/* 9. Write log record of the insert */
	page_cur_insert_rec_write_log(insert_rec, rec_size, current_rec,
				index, mtr);
	
	if (UNIV_LIKELY_NULL(heap)) {
		mem_heap_free(heap);
	}
	return(insert_rec);
}

/**************************************************************
Writes a log record of copying a record list end to a new created page. */
UNIV_INLINE
byte*
page_copy_rec_list_to_created_page_write_log(
/*=========================================*/
				/* out: 4-byte field where to
				write the log data length */
	page_t*		page,	/* in: index page */
	dict_index_t*	index,	/* in: record descriptor */
	mtr_t*		mtr)	/* in: mtr */
{
	byte*	log_ptr;

	ut_ad(!!page_is_comp(page) == index->table->comp);

	log_ptr = mlog_open_and_write_index(mtr, page, index,
			page_is_comp(page)
			? MLOG_COMP_LIST_END_COPY_CREATED
			: MLOG_LIST_END_COPY_CREATED, 4);
	ut_a(log_ptr);
	mlog_close(mtr, log_ptr + 4);

	return(log_ptr);
}

/**************************************************************
Parses a log record of copying a record list end to a new created page. */

byte*
page_parse_copy_rec_list_to_created_page(
/*=====================================*/
				/* out: end of log record or NULL */
	byte*		ptr,	/* in: buffer */
	byte*		end_ptr,/* in: buffer end */
	dict_index_t*	index,	/* in: record descriptor */
	page_t*		page,	/* in: page or NULL */
	mtr_t*		mtr)	/* in: mtr or NULL */
{
	byte*	rec_end;
	ulint	log_data_len;
	
	if (ptr + 4 > end_ptr) {

		return(NULL);
	}

	log_data_len = mach_read_from_4(ptr);
	ptr += 4;

	rec_end = ptr + log_data_len;

	if (rec_end > end_ptr) {

		return(NULL);
	}

	if (!page) {

		return(rec_end);
	}

	while (ptr < rec_end) {
		ptr = page_cur_parse_insert_rec(TRUE, ptr, end_ptr,
							index, page, mtr);
	}

	ut_a(ptr == rec_end);
	
	page_header_set_ptr(page, PAGE_LAST_INSERT, NULL);
	page_header_set_field(page, PAGE_DIRECTION, PAGE_NO_DIRECTION);
	page_header_set_field(page, PAGE_N_DIRECTION, 0);

	return(rec_end);	
}

/*****************************************************************
Copies records from page to a newly created page, from a given record onward,
including that record. Infimum and supremum records are not copied. */

void
page_copy_rec_list_end_to_created_page(
/*===================================*/
	page_t*		new_page,	/* in: index page to copy to */
	page_t*		page,		/* in: index page */
	rec_t*		rec,		/* in: first record to copy */
	dict_index_t*	index,		/* in: record descriptor */
	mtr_t*		mtr)		/* in: mtr */
{
	page_dir_slot_t* slot = 0; /* remove warning */
	byte*	heap_top;
	rec_t*	insert_rec = 0; /* remove warning */
	rec_t*	prev_rec;
	ulint	count;
	ulint	n_recs;
	ulint	slot_index;
	ulint	rec_size;
	ulint	log_mode;
	byte*	log_ptr;
	ulint	log_data_len;
	ulint		comp		= page_is_comp(page);
	mem_heap_t*	heap		= NULL;
	ulint		offsets_[REC_OFFS_NORMAL_SIZE];
	ulint*		offsets		= offsets_;
	*offsets_ = (sizeof offsets_) / sizeof *offsets_;
	
	ut_ad(page_dir_get_n_heap(new_page) == 2);
	ut_ad(page != new_page);
	ut_ad(comp == page_is_comp(new_page));
	
	if (rec == page_get_infimum_rec(page)) {

		rec = page_rec_get_next(rec);
	}

	if (rec == page_get_supremum_rec(page)) {

		return;
	}
	
#ifdef UNIV_DEBUG
	/* To pass the debug tests we have to set these dummy values
	in the debug version */
	page_dir_set_n_slots(new_page, UNIV_PAGE_SIZE / 2);
	page_header_set_ptr(new_page, PAGE_HEAP_TOP,
					new_page + UNIV_PAGE_SIZE - 1);
#endif

	log_ptr = page_copy_rec_list_to_created_page_write_log(new_page,
								index, mtr);

	log_data_len = dyn_array_get_data_size(&(mtr->log));

	/* Individual inserts are logged in a shorter form */

	log_mode = mtr_set_log_mode(mtr, MTR_LOG_SHORT_INSERTS);
	
	prev_rec = page_get_infimum_rec(new_page);
	if (comp) {
		heap_top = new_page + PAGE_NEW_SUPREMUM_END;
	} else {
		heap_top = new_page + PAGE_OLD_SUPREMUM_END;
	}
	count = 0;
	slot_index = 0;
	n_recs = 0;

	/* should be do ... until, comment by Jani */
	while (rec != page_get_supremum_rec(page)) {
		offsets = rec_get_offsets(rec, index, offsets,
					ULINT_UNDEFINED, &heap);
		insert_rec = rec_copy(heap_top, rec, offsets);

		rec_set_next_offs(prev_rec, comp, insert_rec - new_page);

		rec_set_n_owned(insert_rec, comp, 0);
		rec_set_heap_no(insert_rec, comp, 2 + n_recs);

		rec_size = rec_offs_size(offsets);

		heap_top = heap_top + rec_size;
		
		ut_ad(heap_top < new_page + UNIV_PAGE_SIZE);

		count++;
		n_recs++;

		if (count == (PAGE_DIR_SLOT_MAX_N_OWNED + 1) / 2) {

			slot_index++;

			slot = page_dir_get_nth_slot(new_page, slot_index);

			page_dir_slot_set_rec(slot, insert_rec);
			page_dir_slot_set_n_owned(slot, count);

			count = 0;
		}
		
 		page_cur_insert_rec_write_log(insert_rec, rec_size, prev_rec,
								index, mtr);
		prev_rec = insert_rec;
		rec = page_rec_get_next(rec);
	}

	if ((slot_index > 0) && (count + 1
				+ (PAGE_DIR_SLOT_MAX_N_OWNED + 1) / 2
			     	 <= PAGE_DIR_SLOT_MAX_N_OWNED)) {
		/* We can merge the two last dir slots. This operation is
		here to make this function imitate exactly the equivalent
		task made using page_cur_insert_rec, which we use in database
		recovery to reproduce the task performed by this function.
		To be able to check the correctness of recovery, it is good
		that it imitates exactly. */

		count += (PAGE_DIR_SLOT_MAX_N_OWNED + 1) / 2;
		
		page_dir_slot_set_n_owned(slot, 0);

		slot_index--;
	}

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

	log_data_len = dyn_array_get_data_size(&(mtr->log)) - log_data_len;

	ut_a(log_data_len < 100 * UNIV_PAGE_SIZE);

	mach_write_to_4(log_ptr, log_data_len);
	
	rec_set_next_offs(insert_rec, comp,
				comp ? PAGE_NEW_SUPREMUM : PAGE_OLD_SUPREMUM);

	slot = page_dir_get_nth_slot(new_page, 1 + slot_index);

	page_dir_slot_set_rec(slot, page_get_supremum_rec(new_page));
	page_dir_slot_set_n_owned(slot, count + 1);

	page_dir_set_n_slots(new_page, 2 + slot_index);
	page_header_set_ptr(new_page, PAGE_HEAP_TOP, heap_top);
	page_dir_set_n_heap(new_page, 2 + n_recs);
	page_header_set_field(new_page, PAGE_N_RECS, n_recs);
	
	page_header_set_ptr(new_page, PAGE_LAST_INSERT, NULL);
	page_header_set_field(new_page, PAGE_DIRECTION, PAGE_NO_DIRECTION);
	page_header_set_field(new_page, PAGE_N_DIRECTION, 0);

	/* Restore the log mode */

	mtr_set_log_mode(mtr, log_mode);
}

/***************************************************************
Writes log record of a record delete on a page. */
UNIV_INLINE
void
page_cur_delete_rec_write_log(
/*==========================*/
	rec_t*		rec,	/* in: record to be deleted */
	dict_index_t*	index,	/* in: record descriptor */
	mtr_t*		mtr)	/* in: mini-transaction handle */
{
	byte*	log_ptr;

	ut_ad(!!page_rec_is_comp(rec) == index->table->comp);

	log_ptr = mlog_open_and_write_index(mtr, rec, index,
			page_rec_is_comp(rec)
			? MLOG_COMP_REC_DELETE
			: MLOG_REC_DELETE, 2);

	if (!log_ptr) {
		/* Logging in mtr is switched off during crash recovery:
		in that case mlog_open returns NULL */
		return;
	}

	/* Write the cursor rec offset as a 2-byte ulint */
	mach_write_to_2(log_ptr, ut_align_offset(rec, UNIV_PAGE_SIZE));

	mlog_close(mtr, log_ptr + 2);
}	

/***************************************************************
Parses log record of a record delete on a page. */

byte*
page_cur_parse_delete_rec(
/*======================*/
				/* out: pointer to record end or NULL */
	byte*		ptr,	/* in: buffer */
	byte*		end_ptr,/* in: buffer end */
	dict_index_t*	index,	/* in: record descriptor */
	page_t*		page,	/* in: page or NULL */
	mtr_t*		mtr)	/* in: mtr or NULL */
{
	ulint		offset;
	page_cur_t	cursor;
	
	if (end_ptr < ptr + 2) {

		return(NULL);
	}

	/* Read the cursor rec offset as a 2-byte ulint */
	offset = mach_read_from_2(ptr);
	ptr += 2;

	ut_a(offset <= UNIV_PAGE_SIZE);

	if (page) {
		mem_heap_t*	heap		= NULL;
		ulint		offsets_[REC_OFFS_NORMAL_SIZE];
		rec_t*		rec		= page + offset;
		*offsets_ = (sizeof offsets_) / sizeof *offsets_;

		page_cur_position(rec, &cursor);

		page_cur_delete_rec(&cursor, index,
				rec_get_offsets(rec, index, offsets_,
				ULINT_UNDEFINED, &heap), mtr);
		if (UNIV_LIKELY_NULL(heap)) {
			mem_heap_free(heap);
		}
	}

	return(ptr);
}	

/***************************************************************
Deletes a record at the page cursor. The cursor is moved to the next
record after the deleted one. */

void
page_cur_delete_rec(
/*================*/
	page_cur_t*  	cursor,	/* in: a page cursor */
	dict_index_t*	index,	/* in: record descriptor */
	const ulint*	offsets,/* in: rec_get_offsets(cursor->rec, index) */
	mtr_t*		mtr)	/* in: mini-transaction handle */
{
	page_dir_slot_t* cur_dir_slot;
	page_dir_slot_t* prev_slot;
	page_t*		page;
	rec_t*		current_rec;
	rec_t*		prev_rec	= NULL;
	rec_t*		next_rec;
	ulint		cur_slot_no;
	ulint		cur_n_owned;
	rec_t*		rec;
	
	ut_ad(cursor && mtr);
	
	page = page_cur_get_page(cursor);
	current_rec = cursor->rec;
	ut_ad(rec_offs_validate(current_rec, index, offsets));
	ut_ad(!!page_is_comp(page) == index->table->comp);

	/* The record must not be the supremum or infimum record. */
	ut_ad(current_rec != page_get_supremum_rec(page));	
	ut_ad(current_rec != page_get_infimum_rec(page));	
	
	/* Save to local variables some data associated with current_rec */
	cur_slot_no = page_dir_find_owner_slot(current_rec);
	cur_dir_slot = page_dir_get_nth_slot(page, cur_slot_no);
	cur_n_owned = page_dir_slot_get_n_owned(cur_dir_slot);

	/* 0. Write the log record */
	page_cur_delete_rec_write_log(current_rec, index, mtr);

	/* 1. Reset the last insert info in the page header and increment
	the modify clock for the frame */

	page_header_set_ptr(page, PAGE_LAST_INSERT, NULL);

	/* The page gets invalid for optimistic searches: increment the
	frame modify clock */

	buf_frame_modify_clock_inc(page);
	
	/* 2. Find the next and the previous record. Note that the cursor is
	left at the next record. */

	ut_ad(cur_slot_no > 0);
	prev_slot = page_dir_get_nth_slot(page, cur_slot_no - 1);
	
	rec = page_dir_slot_get_rec(prev_slot);
	
	/* rec now points to the record of the previous directory slot. Look
	for the immediate predecessor of current_rec in a loop. */

	while(current_rec != rec) {
		prev_rec = rec;
		rec = page_rec_get_next(rec);
	}

	page_cur_move_to_next(cursor);
	next_rec = cursor->rec;
	
	/* 3. Remove the record from the linked list of records */

	page_rec_set_next(prev_rec, next_rec);
	page_header_set_field(page, PAGE_N_RECS,
				(ulint)(page_get_n_recs(page) - 1));

	/* 4. If the deleted record is pointed to by a dir slot, update the
	record pointer in slot. In the following if-clause we assume that
	prev_rec is owned by the same slot, i.e., PAGE_DIR_SLOT_MIN_N_OWNED
	>= 2. */
	
	ut_ad(PAGE_DIR_SLOT_MIN_N_OWNED >= 2);
	ut_ad(cur_n_owned > 1);

	if (current_rec == page_dir_slot_get_rec(cur_dir_slot)) {
		page_dir_slot_set_rec(cur_dir_slot, prev_rec);
	}
	
	/* 5. Update the number of owned records of the slot */

	page_dir_slot_set_n_owned(cur_dir_slot, cur_n_owned - 1);

	/* 6. Free the memory occupied by the record */
	page_mem_free(page, current_rec, offsets);

	/* 7. Now we have decremented the number of owned records of the slot.
	If the number drops below PAGE_DIR_SLOT_MIN_N_OWNED, we balance the
	slots. */
	
	if (cur_n_owned <= PAGE_DIR_SLOT_MIN_N_OWNED) {
		page_dir_balance_slot(page, cur_slot_no);
	}
}