lock0lock.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

	bit_index = i % 8;

	b = (ulint)*((byte*)lock + sizeof(lock_t) + byte_index);

	return(ut_bit_get_nth(b, bit_index));
}	

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

#define lock_mutex_enter_kernel()	mutex_enter(&kernel_mutex)
#define lock_mutex_exit_kernel()	mutex_exit(&kernel_mutex)

/*************************************************************************
Checks that a transaction id is sensible, i.e., not in the future. */

ibool
lock_check_trx_id_sanity(
/*=====================*/
					/* out: TRUE if ok */
	dulint		trx_id,		/* in: trx id */
	rec_t*		rec,		/* in: user record */
	dict_index_t*	index,		/* in: index */
	const ulint*	offsets,	/* in: rec_get_offsets(rec, index) */
	ibool		has_kernel_mutex)/* in: TRUE if the caller owns the
					kernel mutex */
{
	ibool	is_ok		= TRUE;
	
	ut_ad(rec_offs_validate(rec, index, offsets));

	if (!has_kernel_mutex) {
		mutex_enter(&kernel_mutex);
	}

	/* A sanity check: the trx_id in rec must be smaller than the global
	trx id counter */

	if (ut_dulint_cmp(trx_id, trx_sys->max_trx_id) >= 0) {
		ut_print_timestamp(stderr);
		fputs("  InnoDB: Error: transaction id associated"
			" with record\n",
			stderr);
		rec_print_new(stderr, rec, offsets);
		fputs("InnoDB: in ", stderr);
		dict_index_name_print(stderr, NULL, index);
		fprintf(stderr, "\n"
"InnoDB: is %lu %lu which is higher than the global trx id counter %lu %lu!\n"
"InnoDB: The table is corrupt. You have to do dump + drop + reimport.\n",
			       (ulong) ut_dulint_get_high(trx_id),
			       (ulong) ut_dulint_get_low(trx_id),
			       (ulong) ut_dulint_get_high(trx_sys->max_trx_id),
			       (ulong) ut_dulint_get_low(trx_sys->max_trx_id));

		is_ok = FALSE;
	}
	
	if (!has_kernel_mutex) {
		mutex_exit(&kernel_mutex);
	}

	return(is_ok);
}

/*************************************************************************
Checks that a record is seen in a consistent read. */

ibool
lock_clust_rec_cons_read_sees(
/*==========================*/
				/* out: TRUE if sees, or FALSE if an earlier
				version of the record should be retrieved */
	rec_t*		rec,	/* in: user record which should be read or
				passed over by a read cursor */
	dict_index_t*	index,	/* in: clustered index */
	const ulint*	offsets,/* in: rec_get_offsets(rec, index) */
	read_view_t*	view)	/* in: consistent read view */
{
	dulint	trx_id;

	ut_ad(index->type & DICT_CLUSTERED);
	ut_ad(page_rec_is_user_rec(rec));
	ut_ad(rec_offs_validate(rec, index, offsets));

	/* NOTE that we call this function while holding the search
	system latch. To obey the latching order we must NOT reserve the
	kernel mutex here! */

	trx_id = row_get_rec_trx_id(rec, index, offsets);
	
	return(read_view_sees_trx_id(view, trx_id));
}

/*************************************************************************
Checks that a non-clustered index record is seen in a consistent read. */

ulint
lock_sec_rec_cons_read_sees(
/*========================*/
				/* out: TRUE if certainly sees, or FALSE if an
				earlier version of the clustered index record
				might be needed: NOTE that a non-clustered
				index page contains so little information on
				its modifications that also in the case FALSE,
				the present version of rec may be the right,
				but we must check this from the clustered
				index record */
	rec_t*		rec,	/* in: user record which should be read or
				passed over by a read cursor */
	dict_index_t*	index,	/* in: non-clustered index */
	read_view_t*	view)	/* in: consistent read view */
{
	dulint	max_trx_id;
	
	UT_NOT_USED(index);
	
	ut_ad(!(index->type & DICT_CLUSTERED));
	ut_ad(page_rec_is_user_rec(rec));

	/* NOTE that we might call this function while holding the search
	system latch. To obey the latching order we must NOT reserve the
	kernel mutex here! */

	if (recv_recovery_is_on()) {

		return(FALSE);
	}

	max_trx_id = page_get_max_trx_id(buf_frame_align(rec));

	if (ut_dulint_cmp(max_trx_id, view->up_limit_id) >= 0) {

		return(FALSE);
	}

	return(TRUE);
}

/*************************************************************************
Creates the lock system at database start. */

void
lock_sys_create(
/*============*/
	ulint	n_cells)	/* in: number of slots in lock hash table */
{
	lock_sys = mem_alloc(sizeof(lock_sys_t));

	lock_sys->rec_hash = hash_create(n_cells);

	/* hash_create_mutexes(lock_sys->rec_hash, 2, SYNC_REC_LOCK); */

	lock_latest_err_file = os_file_create_tmpfile();
	ut_a(lock_latest_err_file);
}

/*************************************************************************
Gets the size of a lock struct. */

ulint
lock_get_size(void)
/*===============*/
			/* out: size in bytes */
{
	return((ulint)sizeof(lock_t));
}

/*************************************************************************
Gets the mode of a lock. */
UNIV_INLINE
ulint
lock_get_mode(
/*==========*/
			/* out: mode */
	lock_t*	lock)	/* in: lock */
{
	ut_ad(lock);

	return(lock->type_mode & LOCK_MODE_MASK);
}

/*************************************************************************
Gets the wait flag of a lock. */
UNIV_INLINE
ibool
lock_get_wait(
/*==========*/
			/* out: TRUE if waiting */
	lock_t*	lock)	/* in: lock */
{
	ut_ad(lock);

	if (lock->type_mode & LOCK_WAIT) {

		return(TRUE);
	}

	return(FALSE);
}

/*************************************************************************
Gets the source table of an ALTER TABLE transaction.  The table must be
covered by an IX or IS table lock. */

dict_table_t*
lock_get_src_table(
/*===============*/
				/* out: the source table of transaction,
				if it is covered by an IX or IS table lock;
				dest if there is no source table, and
				NULL if the transaction is locking more than
				two tables or an inconsistency is found */
	trx_t*		trx,	/* in: transaction */
	dict_table_t*	dest,	/* in: destination of ALTER TABLE */
	ulint*		mode)	/* out: lock mode of the source table */
{
	dict_table_t*	src;
	lock_t*		lock;

	src = NULL;
	*mode = LOCK_NONE;

	for (lock = UT_LIST_GET_FIRST(trx->trx_locks);
	     lock;
	     lock = UT_LIST_GET_NEXT(trx_locks, lock)) {
		lock_table_t*	tab_lock;
		ulint		lock_mode;
		if (!(lock_get_type(lock) & LOCK_TABLE)) {
			/* We are only interested in table locks. */
			continue;
		}
		tab_lock = &lock->un_member.tab_lock;
		if (dest == tab_lock->table) {
			/* We are not interested in the destination table. */
			continue;
		} else if (!src) {
			/* This presumably is the source table. */
			src = tab_lock->table;
			if (UT_LIST_GET_LEN(src->locks) != 1 ||
			    UT_LIST_GET_FIRST(src->locks) != lock) {
				/* We only support the case when
				there is only one lock on this table. */
				return(NULL);
			}
		} else if (src != tab_lock->table) {
			/* The transaction is locking more than
			two tables (src and dest): abort */
			return(NULL);
		}

		/* Check that the source table is locked by
		LOCK_IX or LOCK_IS. */
		lock_mode = lock_get_mode(lock);
		switch (lock_mode) {
		case LOCK_IX:
		case LOCK_IS:
			if (*mode != LOCK_NONE && *mode != lock_mode) {
				/* There are multiple locks on src. */
				return(NULL);
			}
			*mode = lock_mode;
			break;
		}
	}

	if (!src) {
		/* No source table lock found: flag the situation to caller */
		src = dest;
	}

	return(src);
}

/*************************************************************************
Determine if the given table is exclusively "owned" by the given
transaction, i.e., transaction holds LOCK_IX and possibly LOCK_AUTO_INC
on the table. */

ibool
lock_is_table_exclusive(
/*====================*/
				/* out: TRUE if table is only locked by trx,
				with LOCK_IX, and possibly LOCK_AUTO_INC */
	dict_table_t*	table,	/* in: table */
	trx_t*		trx)	/* in: transaction */
{
	lock_t*	lock;
	ibool	ok	= FALSE;

	ut_ad(table && trx);

	for (lock = UT_LIST_GET_FIRST(table->locks);
	     lock;
	     lock = UT_LIST_GET_NEXT(locks, &lock->un_member.tab_lock)) {
		if (lock->trx != trx) {
			/* A lock on the table is held
			by some other transaction. */
			return(FALSE);
		}

		if (!(lock_get_type(lock) & LOCK_TABLE)) {
			/* We are interested in table locks only. */
			continue;
		}

		switch (lock_get_mode(lock)) {
		case LOCK_IX:
			ok = TRUE;
			break;
		case LOCK_AUTO_INC:
			/* It is allowed for trx to hold an
			auto_increment lock. */
			break;
		default:
			/* Other table locks than LOCK_IX are not allowed. */
			return(FALSE);
		}
	}

	return(ok);
}

/*************************************************************************
Sets the wait flag of a lock and the back pointer in trx to lock. */
UNIV_INLINE
void
lock_set_lock_and_trx_wait(
/*=======================*/
	lock_t*	lock,	/* in: lock */
	trx_t*	trx)	/* in: trx */
{
	ut_ad(lock);
	ut_ad(trx->wait_lock == NULL);
	
	trx->wait_lock = lock;
 	lock->type_mode = lock->type_mode | LOCK_WAIT;
}

/**************************************************************************
The back pointer to a waiting lock request in the transaction is set to NULL
and the wait bit in lock type_mode is reset. */
UNIV_INLINE
void
lock_reset_lock_and_trx_wait(
/*=========================*/
	lock_t*	lock)	/* in: record lock */
{
	ut_ad((lock->trx)->wait_lock == lock);
	ut_ad(lock_get_wait(lock));

	/* Reset the back pointer in trx to this waiting lock request */

	(lock->trx)->wait_lock = NULL;
 	lock->type_mode = lock->type_mode & ~LOCK_WAIT;
}

/*************************************************************************
Gets the gap flag of a record lock. */
UNIV_INLINE
ibool
lock_rec_get_gap(
/*=============*/
			/* out: TRUE if gap flag set */
	lock_t*	lock)	/* in: record lock */
{
	ut_ad(lock);
	ut_ad(lock_get_type(lock) == LOCK_REC);

	if (lock->type_mode & LOCK_GAP) {

		return(TRUE);
	}

	return(FALSE);
}

/*************************************************************************
Gets the LOCK_REC_NOT_GAP flag of a record lock. */
UNIV_INLINE
ibool
lock_rec_get_rec_not_gap(
/*=====================*/
			/* out: TRUE if LOCK_REC_NOT_GAP flag set */
	lock_t*	lock)	/* in: record lock */
{
	ut_ad(lock);
	ut_ad(lock_get_type(lock) == LOCK_REC);

	if (lock->type_mode & LOCK_REC_NOT_GAP) {

		return(TRUE);
	}

	return(FALSE);
}

/*************************************************************************
Gets the waiting insert flag of a record lock. */
UNIV_INLINE
ibool
lock_rec_get_insert_intention(
/*==========================*/
			/* out: TRUE if gap flag set */
	lock_t*	lock)	/* in: record lock */
{
	ut_ad(lock);
	ut_ad(lock_get_type(lock) == LOCK_REC);

	if (lock->type_mode & LOCK_INSERT_INTENTION) {

		return(TRUE);
	}

	return(FALSE);
}

/*************************************************************************
Calculates if lock mode 1 is stronger or equal to lock mode 2. */
UNIV_INLINE
ibool
lock_mode_stronger_or_eq(
/*=====================*/
			/* out: TRUE if mode1 stronger or equal to mode2 */
	ulint	mode1,	/* in: lock mode */
	ulint	mode2)	/* in: lock mode */
{
	ut_ad(mode1 == LOCK_X || mode1 == LOCK_S || mode1 == LOCK_IX
				|| mode1 == LOCK_IS || mode1 == LOCK_AUTO_INC);
	ut_ad(mode2 == LOCK_X || mode2 == LOCK_S || mode2 == LOCK_IX
				|| mode2 == LOCK_IS || mode2 == LOCK_AUTO_INC);
	if (mode1 == LOCK_X) {

		return(TRUE);

	} else if (mode1 == LOCK_AUTO_INC && mode2 == LOCK_AUTO_INC) {

		return(TRUE);

	} else if (mode1 == LOCK_S
				&& (mode2 == LOCK_S || mode2 == LOCK_IS)) {