Editing Record locking (section)

===Exclusive locks===
Exclusive locks are exclusively held by a single entity, usually for the purpose of writing to the record. If the locking schema was represented by a list, the '''holder list''' would contain only one entry. Since this type of lock effectively blocks any other entity that requires the lock from processing, care must be used to:
*ensure the lock is held for the shortest time possible;
*not hold the lock across system or function calls where the entity is no longer running on the processor – this can lead to deadlock;
*ensure that if the entity is unexpectedly exited for any reason, the lock is freed.

Non-holders of the lock (a.k.a. '''waiters''') can be held in a list that is serviced in a round-robin fashion, or in a [[FIFO (computing and electronics)|FIFO]] queue. This would ensure that any possible waiter would get equal chance to obtain the lock and not be locked out. To further speed up the process, if an entity has gone to sleep waiting for a lock, performance is improved if the entity is notified of the grant, instead of discovering it on some sort of system timeout driven wake-up.