dict0boot.ic

来自「这是linux下运行的mysql软件包,可用于linux 下安装 php + m」· IC 代码 · 共 73 行

/******************************************************
Data dictionary creation and booting

(c) 1996 Innobase Oy

Created 4/18/1996 Heikki Tuuri
*******************************************************/

/**************************************************************************
Writes the current value of the row id counter to the dictionary header file
page. */

void
dict_hdr_flush_row_id(void);
/*=======================*/


/**************************************************************************
Returns a new row id. */
UNIV_INLINE
dulint
dict_sys_get_new_row_id(void)
/*=========================*/
			/* out: the new id */
{
	dulint	id;

	mutex_enter(&(dict_sys->mutex));

	id = dict_sys->row_id;
	
	if (0 == (ut_dulint_get_low(id) % DICT_HDR_ROW_ID_WRITE_MARGIN)) {

		dict_hdr_flush_row_id();
	}

	UT_DULINT_INC(dict_sys->row_id);

	mutex_exit(&(dict_sys->mutex));

	return(id);
}			

/**************************************************************************
Reads a row id from a record or other 6-byte stored form. */
UNIV_INLINE
dulint
dict_sys_read_row_id(
/*=================*/
			/* out: row id */
	byte*	field)	/* in: record field */
{
	ut_ad(DATA_ROW_ID_LEN == 6);

	return(mach_read_from_6(field));
}				

/**************************************************************************
Writes a row id to a record or other 6-byte stored form. */
UNIV_INLINE
void
dict_sys_write_row_id(
/*==================*/
	byte*	field,	/* in: record field */
	dulint	row_id)	/* in: row id */
{
	ut_ad(DATA_ROW_ID_LEN == 6);

	mach_write_to_6(field, row_id);
}