btr0cur.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

	if (UNIV_UNLIKELY(err != DB_SUCCESS)) {

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

	block = buf_block_align(rec);
	ut_ad(!!page_is_comp(buf_block_get_frame(block))
				== index->table->comp);

	if (block->is_hashed) {
		/* The function row_upd_changes_ord_field_binary works only
		if the update vector was built for a clustered index, we must
		NOT call it if index is secondary */

	        if (!(index->type & DICT_CLUSTERED)
		    || row_upd_changes_ord_field_binary(NULL, index, update)) {

		        /* Remove possible hash index pointer to this record */
	                btr_search_update_hash_on_delete(cursor);
	        }

		rw_lock_x_lock(&btr_search_latch);
	}

	if (!(flags & BTR_KEEP_SYS_FLAG)) {
		row_upd_rec_sys_fields(rec, index, offsets, trx, roll_ptr);
	}

	/* FIXME: in a mixed tree, all records may not have enough ordering
	fields for btr search: */

	was_delete_marked = rec_get_deleted_flag(rec,
				page_is_comp(buf_block_get_frame(block)));

	row_upd_rec_in_place(rec, offsets, update);

	if (block->is_hashed) {
		rw_lock_x_unlock(&btr_search_latch);
	}

	btr_cur_update_in_place_log(flags, rec, index, update, trx, roll_ptr,
									mtr);
	if (was_delete_marked && !rec_get_deleted_flag(rec,
				page_is_comp(buf_block_get_frame(block)))) {
		/* The new updated record owns its possible externally
		stored fields */

		btr_cur_unmark_extern_fields(rec, mtr, offsets);
	}

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

/*****************************************************************
Tries to update a record on a page in an index tree. It is assumed that mtr
holds an x-latch on the page. The operation does not succeed if there is too
little space on the page or if the update would result in too empty a page,
so that tree compression is recommended. We assume here that the ordering
fields of the record do not change. */

ulint
btr_cur_optimistic_update(
/*======================*/
				/* out: DB_SUCCESS, or DB_OVERFLOW if the
				updated record does not fit, DB_UNDERFLOW
				if the page would become too empty */
	ulint		flags,	/* in: undo logging and locking flags */
	btr_cur_t*	cursor,	/* in: cursor on the record to update;
				cursor stays valid and positioned on the
				same record */
	upd_t*		update,	/* in: update vector; this must also
				contain trx id and roll ptr fields */
	ulint		cmpl_info,/* in: compiler info on secondary index
				updates */
	que_thr_t*	thr,	/* in: query thread */
	mtr_t*		mtr)	/* in: mtr */
{
	dict_index_t*	index;
	page_cur_t*	page_cursor;
	ulint		err;
	page_t*		page;
	rec_t*		rec;
	ulint		max_size;
	ulint		new_rec_size;
	ulint		old_rec_size;
	dtuple_t*	new_entry;
	dulint		roll_ptr;
	trx_t*		trx;
	mem_heap_t*	heap;
	ibool		reorganized	= FALSE;
	ulint		i;
	ulint*		offsets;

	page = btr_cur_get_page(cursor);
	rec = btr_cur_get_rec(cursor);
	index = cursor->index;
	ut_ad(!!page_rec_is_comp(rec) == index->table->comp);
	
	heap = mem_heap_create(1024);
	offsets = rec_get_offsets(rec, index, NULL, ULINT_UNDEFINED, &heap);

#ifdef UNIV_DEBUG
	if (btr_cur_print_record_ops && thr) {
		btr_cur_trx_report(thr_get_trx(thr), index, "update ");
		rec_print_new(stderr, rec, offsets);
	}
#endif /* UNIV_DEBUG */

	ut_ad(mtr_memo_contains(mtr, buf_block_align(page),
							MTR_MEMO_PAGE_X_FIX));
	if (!row_upd_changes_field_size_or_external(index, offsets, update)) {

		/* The simplest and the most common case: the update does not
		change the size of any field and none of the updated fields is
		externally stored in rec or update */
		mem_heap_free(heap);
		return(btr_cur_update_in_place(flags, cursor, update,
							cmpl_info, thr, mtr));
	}

	for (i = 0; i < upd_get_n_fields(update); i++) {
		if (upd_get_nth_field(update, i)->extern_storage) {

			/* Externally stored fields are treated in pessimistic
			update */

			mem_heap_free(heap);
			return(DB_OVERFLOW);
		}
	}

	if (rec_offs_any_extern(offsets)) {
		/* Externally stored fields are treated in pessimistic
		update */

		mem_heap_free(heap);
		return(DB_OVERFLOW);
	}
	
	page_cursor = btr_cur_get_page_cur(cursor);
	
	new_entry = row_rec_to_index_entry(ROW_COPY_DATA, index, rec, heap);

	row_upd_index_replace_new_col_vals_index_pos(new_entry, index, update,
									NULL);
	old_rec_size = rec_offs_size(offsets);
	new_rec_size = rec_get_converted_size(index, new_entry);
	
	if (UNIV_UNLIKELY(new_rec_size >= page_get_free_space_of_empty(
				page_is_comp(page)) / 2)) {

		mem_heap_free(heap);		

		return(DB_OVERFLOW);
	}

	max_size = old_rec_size
			+ page_get_max_insert_size_after_reorganize(page, 1);

	if (UNIV_UNLIKELY(page_get_data_size(page)
					- old_rec_size + new_rec_size
					< BTR_CUR_PAGE_COMPRESS_LIMIT)) {

		/* The page would become too empty */

		mem_heap_free(heap);

		return(DB_UNDERFLOW);
	}

	if (!(((max_size >= BTR_CUR_PAGE_REORGANIZE_LIMIT)
	       				&& (max_size >= new_rec_size))
	      || (page_get_n_recs(page) <= 1))) {

		/* There was not enough space, or it did not pay to
		reorganize: for simplicity, we decide what to do assuming a
		reorganization is needed, though it might not be necessary */

		mem_heap_free(heap);		

		return(DB_OVERFLOW);
	}

	/* Do lock checking and undo logging */
	err = btr_cur_upd_lock_and_undo(flags, cursor, update, cmpl_info, thr,
								&roll_ptr);
	if (err != DB_SUCCESS) {

		mem_heap_free(heap);

		return(err);
	}
        
        /* Ok, we may do the replacement. Store on the page infimum the
	explicit locks on rec, before deleting rec (see the comment in
	.._pessimistic_update). */

	lock_rec_store_on_page_infimum(page, rec);

	btr_search_update_hash_on_delete(cursor);

	page_cur_delete_rec(page_cursor, index, offsets, mtr);

	page_cur_move_to_prev(page_cursor);
        
	trx = thr_get_trx(thr);

	if (!(flags & BTR_KEEP_SYS_FLAG)) {
		row_upd_index_entry_sys_field(new_entry, index, DATA_ROLL_PTR,
								roll_ptr);
		row_upd_index_entry_sys_field(new_entry, index, DATA_TRX_ID,
								trx->id);
	}

	rec = btr_cur_insert_if_possible(cursor, new_entry, &reorganized, mtr);

	ut_a(rec); /* <- We calculated above the insert would fit */

	if (!rec_get_deleted_flag(rec, page_is_comp(page))) {
		/* The new inserted record owns its possible externally
		stored fields */

		offsets = rec_get_offsets(rec, index, offsets,
						ULINT_UNDEFINED, &heap);
		btr_cur_unmark_extern_fields(rec, mtr, offsets);
	}

	/* Restore the old explicit lock state on the record */

	lock_rec_restore_from_page_infimum(rec, page);

        page_cur_move_to_next(page_cursor);

	mem_heap_free(heap);		

	return(DB_SUCCESS);
}

/*****************************************************************
If, in a split, a new supremum record was created as the predecessor of the
updated record, the supremum record must inherit exactly the locks on the
updated record. In the split it may have inherited locks from the successor
of the updated record, which is not correct. This function restores the
right locks for the new supremum. */
static
void
btr_cur_pess_upd_restore_supremum(
/*==============================*/
	rec_t*	rec,	/* in: updated record */
	mtr_t*	mtr)	/* in: mtr */
{
	page_t*	page;
	page_t*	prev_page;
	ulint	space;
	ulint	prev_page_no;
	
	page = buf_frame_align(rec);

	if (page_rec_get_next(page_get_infimum_rec(page)) != rec) {
		/* Updated record is not the first user record on its page */ 
	
		return;
	}

	space = buf_frame_get_space_id(page);
	prev_page_no = btr_page_get_prev(page, mtr);
	
	ut_ad(prev_page_no != FIL_NULL);
	prev_page = buf_page_get_with_no_latch(space, prev_page_no, mtr);

	/* We must already have an x-latch to prev_page! */
	ut_ad(mtr_memo_contains(mtr, buf_block_align(prev_page),
		      				MTR_MEMO_PAGE_X_FIX));

	lock_rec_reset_and_inherit_gap_locks(page_get_supremum_rec(prev_page),
									rec);
}

/*****************************************************************
Performs an update of a record on a page of a tree. It is assumed
that mtr holds an x-latch on the tree and on the cursor page. If the
update is made on the leaf level, to avoid deadlocks, mtr must also
own x-latches to brothers of page, if those brothers exist. We assume
here that the ordering fields of the record do not change. */

ulint
btr_cur_pessimistic_update(
/*=======================*/
				/* out: DB_SUCCESS or error code */
	ulint		flags,	/* in: undo logging, locking, and rollback
				flags */
	btr_cur_t*	cursor,	/* in: cursor on the record to update */
	big_rec_t**	big_rec,/* out: big rec vector whose fields have to
				be stored externally by the caller, or NULL */
	upd_t*		update,	/* in: update vector; this is allowed also
				contain trx id and roll ptr fields, but
				the values in update vector have no effect */
	ulint		cmpl_info,/* in: compiler info on secondary index
				updates */
	que_thr_t*	thr,	/* in: query thread */
	mtr_t*		mtr)	/* in: mtr */
{
	big_rec_t*	big_rec_vec	= NULL;
	big_rec_t*	dummy_big_rec;
	dict_index_t*	index;
	page_t*		page;
	dict_tree_t*	tree;
	rec_t*		rec;
	page_cur_t*	page_cursor;
	dtuple_t*	new_entry;
	mem_heap_t*	heap;
	ulint		err;
	ulint		optim_err;
	ibool		dummy_reorganized;
	dulint		roll_ptr;
	trx_t*		trx;
	ibool		was_first;
	ibool		success;
	ulint		n_extents	= 0;
	ulint		n_reserved;
	ulint*		ext_vect;
	ulint		n_ext_vect;
	ulint		reserve_flag;
	ulint*		offsets		= NULL;
	
	*big_rec = NULL;
	
	page = btr_cur_get_page(cursor);
	rec = btr_cur_get_rec(cursor);
	index = cursor->index;
	tree = index->tree;

	ut_ad(mtr_memo_contains(mtr, dict_tree_get_lock(tree),
							MTR_MEMO_X_LOCK));
	ut_ad(mtr_memo_contains(mtr, buf_block_align(page),
							MTR_MEMO_PAGE_X_FIX));

	optim_err = btr_cur_optimistic_update(flags, cursor, update,
							cmpl_info, thr, mtr);

	if (optim_err != DB_UNDERFLOW && optim_err != DB_OVERFLOW) {

		return(optim_err);
	}

	/* Do lock checking and undo logging */
	err = btr_cur_upd_lock_and_undo(flags, cursor, update, cmpl_info,
							thr, &roll_ptr);
	if (err != DB_SUCCESS) {

		return(err);
	}

	if (optim_err == DB_OVERFLOW) {
		/* First reserve enough free space for the file segments
		of the index tree, so that the update will not fail because
		of lack of space */

		n_extents = cursor->tree_height / 16 + 3;

		if (flags & BTR_NO_UNDO_LOG_FLAG) {
			reserve_flag = FSP_CLEANING;
		} else {
			reserve_flag = FSP_NORMAL;
		}
		
		success = fsp_reserve_free_extents(&n_reserved,
						index->space,
						n_extents, reserve_flag, mtr);
		if (!success) {
			err = DB_OUT_OF_FILE_SPACE;

			return(err);
		}
	}
	
	heap = mem_heap_create(1024);
	offsets = rec_get_offsets(rec, index, NULL, ULINT_UNDEFINED, &heap);

	trx = thr_get_trx(thr);
	
	new_entry = row_rec_to_index_entry(ROW_COPY_DATA, index, rec, heap);

	row_upd_index_replace_new_col_vals_index_pos(new_entry, index, update,
									heap);
	if (!(flags & BTR_KEEP_SYS_FLAG)) {
		row_upd_index_entry_sys_field(new_entry, index, DATA_ROLL_PTR,
								roll_ptr);
		row_upd_index_entry_sys_field(new_entry, index, DATA_TRX_ID,
								trx->id);
	}

	if (flags & BTR_NO_UNDO_LOG_FLAG) {
		/* We are in a transaction rollback undoing a row
		update: we must free possible externally stored fields
		which got new values in the update, if they are not
		inherited values. They can be inherited if we have
		updated the primary key to another value, and then
		update it back again. */

		ut_a(big_rec_vec == NULL);
		
		btr_rec_free_updated_extern_fields(index, rec, offsets,
			update, TRUE, mtr);
	}

	/* We have to set appropriate extern storage bits in the new
	record to be inserted: we have to remember which fields were such */

	ext_vect = mem_heap_alloc(heap, sizeof(ulint)
					* dict_index_get_n_fields(index));
	ut_ad(!page_is_comp(page) || !rec_get_node_ptr_flag(rec));
	offsets = rec_get_offsets(rec, index, offsets,
					ULINT_UNDEFINED, &heap);
	n_ext_vect = btr_push_update_extern_fields(ext_vect, offsets, update);

	if (UNIV_UNLIKELY(rec_get_converted_size(index, new_entry) >=
		ut_min(page_get_free_space_of_empty(page_is_comp(page)) / 2,
		REC_MAX_DATA_SIZE))) {

                big_rec_vec = dtuple_convert_big_rec(index, new_entry,
                					ext_vect, n_ext_vect);
		if (big_rec_vec == NULL) {

			err = DB_TOO_BIG_RECORD;
			goto return_after_reservations;
		}
	}

	page_cursor = btr_cur_get_page_cur(cursor);

	/* Store state of explicit locks on rec on the page infimum record,
	before deleting rec. The page infimum acts as a dummy carrier of the
	locks, taking care also of lock releases, before we can move the locks
	back on the actual record. There is a special case: if we are
	inserting on the root page and the insert causes a call of
	btr_root_raise_and_insert. Therefore we cannot in the lock system
	delete the lock structs set on the root page even if the root
	page carries just node pointers. */

	lock_rec_store_on_page_infimum(buf_frame_align(rec), rec);

	btr_search_update_hash_on_delete(cursor);

	page_cur_delete_rec(page_cursor, index, offsets, mtr);

	page_cur_move_to_prev(page_cursor);

	rec = btr_cur_insert_if_possible(cursor, new_entry,
						&dummy_reorganized, mtr);
	ut_a(rec || optim_err != DB_UNDERFLOW);

	if (rec) {
		lock_rec_restore_from_page_infimum(rec, page);
		rec_set_field_extern_bits(rec, index,
						ext_vect, n_ext_vect, mtr);

		offsets = rec_get_offsets(rec, index, offsets,
					ULINT_UNDEFINED, &heap);

		if (!rec_get_deleted_flag(rec, rec_offs_comp(offsets))) {
			/* The new inserted record owns its possible externally
			stored fields */
			btr_cur_unmark_extern_fields(rec, mtr, offsets);
		}

		btr_cur_compress_if_useful(cursor, mtr);

		err = DB_SUCCESS;
		goto return_after_reservations;
	}

	if (page_cur_is_before_first(page_cursor)) {
		/* The record to be updated was positioned as the first user
		record on its page */

		was_first = TRUE;
	} else {
		was_first = FALSE;
	}