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California Digital Library deadlock00richiala (User talk:Fæ/IA books#Fork20) (batch #29962) File usage No pages on the English Wikipedia use this file (pages on other projects are not listed).
In a SQL database, a record is typically called a "row". The introduction of granular (subset) locks creates the possibility for a situation called deadlock. Deadlock is possible when incremental locking (locking one entity, then locking one or more additional entities) is used. To illustrate, if two bank customers asked two clerks to obtain ...
Distributed deadlocks can be detected either by constructing a global wait-for graph, from local wait-for graphs at a deadlock detector or by a distributed algorithm like edge chasing. Phantom deadlocks are deadlocks that are detected in a distributed system due to system internal delays but no longer actually exist at the time of detection.
This approach may be used in dealing with deadlocks in concurrent programming if they are believed to be very rare and the cost of detection or prevention is high. A set of processes is deadlocked if each process in the set is waiting for an event that only another process in the set can cause.
California Digital Library deadlock00rich (User talk:Fæ/IA books#Fork20) (batch #29961) File usage No pages on the English Wikipedia use this file (pages on other projects are not listed).
Phantom deadlocks are deadlocks that are falsely detected in a distributed system due to system internal delays but do not actually exist. For example, if a process releases a resource R1 and issues a request for R2 , and the first message is lost or delayed, a coordinator (detector of deadlocks) could falsely conclude a deadlock (if the ...
Banker's algorithm is a resource allocation and deadlock avoidance algorithm developed by Edsger Dijkstra that tests for safety by simulating the allocation of predetermined maximum possible amounts of all resources, and then makes an "s-state" check to test for possible deadlock conditions for all other pending activities, before deciding whether allocation should be allowed to continue.
Deadlock freedom can be expanded to implement one or both of these properties: Lockout-freedom guarantees that any process wishing to enter the critical section will be able to do so eventually. This is distinct from deadlock avoidance , which requires that some waiting process be able to get access to the critical section, but does not require ...