Lock

Locks entries so only one transaction can use tham at a time. More...

Functions
s4_lock_t *	_lock_alloc ()
void	_lock_free (s4_lock_t *lock)
int	_lock_exclusive (s4_lock_t *lock, s4_transaction_t *trans)
int	_lock_shared (s4_lock_t *lock, s4_transaction_t *trans)
void	_lock_unlock_all (s4_transaction_t *trans)

Detailed Description

Locks entries so only one transaction can use tham at a time.

Locks can be locked in three ways, read-only, upgradable and exclusive.

• Read-only is for read-only transactions that know they will not want an exclusive version of the lock later one
• Upgradable is for transactions that might want to upgrade it to an exclusive lock later on.
• Exclusive locks can only be held by one transaction.

Function Documentation

s4_lock_t* _lock_alloc

(

void

)

Referenced by _index_create().

int _lock_exclusive	(	s4_lock_t *	lock,
		s4_transaction_t *	trans
	)

Referenced by _index_lock_exclusive().

void _lock_free

(

s4_lock_t *

lock

)

Referenced by _free_relations(), and _index_free().

int _lock_shared	(	s4_lock_t *	lock,
		s4_transaction_t *	trans
	)

Referenced by _index_lock_shared().

void _lock_unlock_all

(

s4_transaction_t *

trans

)

Referenced by _transaction_dummy_free().