deadlock prevention

following is a classic question about thread deadlock: "The question of dining philosophers" as the last example of this section. The question is this: five philosophers sit around a table, with a bowl of rice and a chopstick in front of each person. Here each philosopher can be regarded as a separate thread, and each chopstick can be regarded as a lock. Each philosopher can sit, think, and eat in one of three states. It is important to note that eve

Deadlock ExampleMulti-threading often encounter deadlock problems, learning the operating system will talk about the deadlock related things, we use Python visual demonstration. One reason for a deadlock is a mutex. Assuming a banking system, user A tries to transfer 100 dollars to User B, while User B tries to transfe

deadlocks are listed at the beginning, so you can avoid deadlocks if you try to destroy any 1 or more of these conditions. The following methods help minimize deadlocks:A) Access the object in the same order;b) Avoid user interaction in the transaction, that is, do not include user interaction during the execution of the transaction; c) keep the transaction short and in a batch; d) SELECT statement Plus with (NOLOCK) hint;SELECT * from TABLE1 with (NOLOCK);SELECT * from TABLE2 with (NOLOCK);Thi

First, the preface MySQL InnoDB, support transaction and row level lock, can use row lock to handle the business such as user's mentioning. The use of MySQL locks sometimes deadlock, to do a good job of deadlock prevention. Second, MySQL row-level lock Row-level locks are divided into shared and exclusive locks. Shared locks: Noun Explanation: Shared lock is

A deadlock occurs when two or more processes compete for resources during execution. Four Conditions for deadlock: 1. mutex condition: A resource can only be used by one process at a time. 2. Request and retention conditions: when a process is blocked by requesting resources, it will not release the obtained resources. (Partial resource allocation) 3. No deprivation condition: the resources obtai

order is invalid. If P1 retains resource R1, P2 retains resource R2, and the system is insecure, because the two processes are pushed forward, a deadlock may occur. For example, when P1 runs to P1: Request (R2), it is blocked because R2 is occupied by P2. When P2 runs to P2: Request (R1, it will also be blocked because R1 is occupied by P1, so a process deadlock occurs. Iv. Handling Methods After a

deadlock prevention strategy. Deadlock prevention Strategy InnoDB engine interior (or all of the database inside), there are a variety of lock types: Transaction lock (Row lock, table lock), Mutex (Protection of internal shared variable operations), RWLock (also known as latch, to protect the internal page read and mo

column so that the range lock is applied to the index, rather than the table itself. This reduces the probability of deadlock. Deadlocks caused by improper promotion order This is also the cause of the deadlock in figure 3. A deadlock loop is formed when multiple transactions use resources improperly. The solution is to use resources in the same order as possib

are linked together to form a sufficient and necessary condition for deadlock. --------------------------------------------------------------------------------------------------------------- ---------- 4, how to solve the deadlock.Three solutions in the operating system: deadlock detection, prevention, and avoidance.①, Prev