lock computer

lock, after the thread gets the memory lock, other threads can not access the memory, in order to achieve simple synchronization in Java, mutex operation.* Understand this principle to understand why synchronized (this) differs from synchronized (static XXX),* Synchronized is to request memory lock for memory block, this keyword represents an object of class.* S

A large number of files need to be processed. Using a php process will be slow. How to lock a file when a process reads a file. Do not allow other processes to read and directly skip this step. Do you want to continue reading other processes? Rename the file being read. After reading the file, rename is returned, which is very inefficient .... A large number of files need to be processed. Using a php process will be slow. How to

This article mainly introduced the PHP program in the file lock, mutual exclusion lock, read-write lock using skills analysis, which focuses on the Sync module and pthreads module use examples, the need for friends can refer to. We hope to help you. File lockFull name advisory file lock, which is mentioned in the book

Original: Lock-free data structure (LOCK-FREE data structures)One weeks ago, I wrote an article about the latch (latches) and spin lock (Spinlocks) in SQL Server. The 2 synchronization primitives (synchronization primitives) are used to protect shared data structures in SQL Server, such as pages in the cache pool (via a latch (latches)), and locks in the

Tags: disable lag tom check update net about lease keepArticles Locking in Microsoft SQL Server (part 12–lock escalation) Http://dba.stackexchange.com/questions/12864/what-is-lock-escalation R2 Lock escalation (Database Engine) ---Forward from Locking in Microsoft SQL Server (part 12–lock escal

MYSQL unlock and lock Table introduction, mysql unlock lock table MySQL lock OverviewCompared with other databases, MySQL locks are relatively simple. The most notable feature is that different storage engines support different locks. For example, the MyISAM and MEMORY storage engines use table-level locking. The BDB storage engine uses page-level locking ), howe

One: Pessimistic lockPessimistic lock, that is, regardless of whether there is a multi-threaded conflict, as long as there is such a possibility, on each access is locked, locking will lead to the contention between the lock, there will be a fight to win or lose, the loser waits.Syncrhoized is an exclusive lock, that is, the thread that occupies the

The previous article introduced the INNODB synchronization mechanism lock: InnoDB Lock Series 1This article describes the transaction lock for InnoDB, only so called transaction lock, because the InnoDB is added as a table or row-level lock to implement the ACID properties o

1. PrefaceMultithreaded programming, we not only want to be able to achieve a logical sequencing between two threads, but also want to two unrelated threads when accessing the same resource, while only one thread can operate on the resources, otherwise there will be unpredictable results.For example, there are two threads need to add 1 to the same counter, we want the result is the counter finally add 2, but may also get to this counter, the first thread to the counter plus 1, but the second thr

In view of the previous introduction of the Swoole, the Swoole server/client and the multi-process mechanism are used to describe the lock. This article mainly introduces the PHP file lock and Process lock Use example, here only for the PHP lock mechanism to explain, because the SQL

First lock information is not part of the file? Next, will the power outage automatically disappear or will never be released (because the process of setting up the lock no longer exists)? Reply content: First lock information is not part of the file?Next, will the power outage automatically disappear or will never be released (because the process of setting

Recently I encountered a problem related to cursor locking. In short, it is related to http://support.microsoft.com/kb/953948. So far, reading Uncommitted has been a good experience, but the customer does not want dirty data. Method. I have never studied the cursor in depth because I think the cursor efficiency is low. This time I will talk about the lock and mention the cursor. 1. Basic ConceptsThe lock is

Thread synchronization, Object level lock, class level lock Synchronization is generally referred to in multi-threading, where a synchronous block code can be executed only in one thread at a time. Java supports multi-threaded execution, so there may be two or more threads accessing the same field or object. Synchronization is a process that keeps all concurrent threads executing synchronously. Synchroniza

Hibernate supports two types of locking mechanisms:The "Pessimistic lock (pessimistic Locking)" and "optimistic Lock (optimisticlocking)" are usually called. Pessimistic lock implementation, often rely on the database provided by the lock mechanism (also only the database layer provides a

One weeks ago, I wrote an article about the latch (latches) and spin lock (Spinlocks) in SQL Server. The 2 synchronization primitives (synchronization primitives) are used to protect shared data structures in SQL Server, such as pages in the cache pool (via a latch (latches)), and locks in the Lock Manager hash table (via a spin lock (Spinlock)). Next you will se

Lock (Locking)In the process of implementing business logic, it is often necessary to ensureexclusivity of data access。 As in the final settlement of the financial system, we want to process the data for a cut-off point in time, and we do not want the data to change again during the settlement process (which may be a few seconds or maybe a few hours). At this point, we need to have some mechanism to ensure that the data will not be modified by the out

Why is the row exclusive lock still unable to lock other processes to select the data row? Example: Table TMP, 10000 data records, with ID as the primary key. Run the following command in process 1 (spid = 55: Run the following command in process 2 (spid = 64: View lock information: We can see that the S lock