drm lock

We used the Synchronized keyword in front of the thread synchronization problem, and today we look at the thread lock lock provided after Java 5.0.The implementation class of the lock interface provides a more flexible and extensive locking object operation than using the Synchronized keyword, and it is an object-oriented way to

I. Use mutex lock 1. initialize mutex Pthread_mutex_t mutex = pthread_mutex_initializer; // static initialization mutex Int pthread_mutex_init (pthread_mutex_t * mutex, pthread_mutexattr_t * ATTR); // dynamically initialize mutex Int pthread_mutex_destory (pthread_mutex_t * mutex); // cancel a mutex. You cannot copy a mutex variable, but you can copy a pointer to the mutex, in this way, multiple functions or threads can share the mutex for synchroniza

Previous Article: Java thread (6) Lock is the interface under the java. util. Concurrent. Locks package,LockThe implementation providesSynchronizedMore extensive lock operations can be obtained by methods and statements. It can handle thread synchronization problems in a more elegant way. We use Java threads (2) the sample code is as follows: Public class locktest {public static void main (string [] ARGs)

Lock Convoy (lock Guard)[1]lock Convoy is a performance degradation problem caused by the use of locks in a multithreaded concurrency environment. Lock convoy problems can arise when multiple threads of the same priority frequently scramble for the same lock, and in general,

the same time to get I and the self-add operation, and finally print output, so I showed the value of 3, followed by three threads are successively get I and make changes, so the output is 4,5,6. If you want to access the shared resource variable I in a sequential manner, you need to add a lock, then the first thought is to use synchronized to control the lock. Public synchronized void Run () { try{

Performance Comparison In JDK1.5, synchronized is inefficient. Because this is a heavyweight operation, its greatest performance impact is the implementation, suspend the thread and recover the thread of the operation need to go into the kernel state of completion, these operations to the system's concurrency has brought great pressure. By contrast, using the lock object provided by Java, the performance is higher. In the multi-threaded environment,

Lock (Locking)In the process of implementing business logic, it is often necessary to guarantee the exclusivity of data access. such as in the final settlement of the financial systemProcessing, we want to process the data for a cut-off point in time, and we don't want to be in the process of closing(may be a few seconds, or maybe a few hours), and the data will change again. At this point, we need to pass some machineSystem to ensure that this data i

I. Introduction to OPTIMISTIC lockingOptimistic lock is a relative pessimistic lock, but also to avoid the database phantom reading, business processing time too long and other reasons cause data processing error of a mechanism, but optimistic lock will not deliberately use the database itself lock mechanism, but accor

This article mainly introduces TM lock in Oracle, understand that when we access the same table object in the database through SQL statements, if more than one user operates on the same table object, it may result in inconsistent data and data inconsistency, please refer to the consistency and atomicity of database transactions. Oracle solves the problem of data inconsistency in multi-threaded situations, mainly through two kinds of locks, one is pess

Why do I need a lock (Concurrency Control )? In a multi-user environment, multiple users may update the same records at the same time, which may cause conflicts. This is a well-known concurrency problem. Typical conflicts include: L loss update: the update of a transaction overwrites the UPDATE results of other transactions, which is called update loss. For example, if user a changes the value from 6 to 2, and user B changes the value from 2 to 6, use

transactions can still Insert new records, but must comply with the search criteria of the current transaction-this means that when the current transaction re-queries the record, there will be phantom read ).1.4 Snapshot The records read by any statement in the snapshot transaction are the data at the startup of the transaction. This is equivalent to a dedicated "snapshot" generated by the database for the transaction when the transaction is started ". In the current transaction, no data change