idn locks

Read/write locks on WindowsThis section briefly introduces the read/write locks and their implementations on Windows. BackgroundWindows does not provide the read/write lock API after Vista and Server2008, that is, the SRW series functions (InitializeSRWLock, AcquireSRWLockShared, AcquireSRWLockExclusive, etc ). considering the current installation volume of Windows XP, only one read/write lock can be implem

ORACLE locks have the following modes:0: none1: null2: Row-S Row sharing (RS): Share table lock3: Row-X (RX): used for Row Modification4: Share lock (S): blocks other DML operations5: S/Row-X dedicated shared rows (SRX): block other transaction operations6: exclusive dedicated (X): used for independent access The larger the number, the higher the lock level, the more operations affected.Level 1 locks includ

Introduction: Advanced I/O includes non-blocking I/O, record locks, System V-flow mechanisms, I/O multiplexing (SELECT and poll functions), READV and Writev functions, and storage-mapped I/O.(i) Non-blocking I/OA class of system calls that may cause the process to block forever are:1. If data for some file types does not exist, the read operation may cause the caller to block forever.2, if the data is not immediately accepted by the same type of file,

Talking about high concurrency (vi) Implementation of several spin locks (i) This article has implemented two basic spin locks: Taslock and Ttaslock, their problem is frequent CAS operations, triggering a lot of cache consistency traffic, resulting in poor lock performance. An improvement to Ttaslock is Backofflock, which returns threads in the case of high contention, reduces competition, and reduces cach

, you do not allow any other transaction to manipulate the resource until the exclusive lock is released, preventing multiple operations on the same resource at the same time. Update Lock (U): Prevent deadlock in the lock mode, two transactions to a data resource read first in the case of modification, use of shared and exclusive locks sometimes deadlock phenomenon, and the use of update locks can avoid

until the exclusive lock is released, preventing multiple operations on the same resource at the same time. Update Lock (U): Prevent deadlock in the lock mode, two transactions to a data resource read first in the case of modification, use of shared and exclusive locks sometimes deadlock phenomenon, and the use of update locks can avoid the occurrence of deadlocks. A resource's update lock can only be

In Java5, the lock object is specially provided, and the lock can be used to control the concurrent access of competing resources, which is mainly concentrated under the Java.util.concurrent.locks package, which has three important interfaces condition, Lock, Readwritelock.Condition:Condition the object Monitor method (wait, notify, and Notifyall) into distinct objects to provide multiple wait set (Wait-set) for each object by combining these objects with any Lock implementation.Lock:The lock im

Basic and Control PrimitivesRead/write LockSimilar to mutex, but read-write locks allow for higher parallelism. Its characteristics are: Write exclusive, read share.Read-Write lock status:A read-write lock has three states:1. Lock status in read mode (read lock)2. Lock status in write mode (write lock)3. No lock statusRead/write lock characteristics: When a read-write lock is "write mode plus lock", all threads that lock on the lock are block

Objective There are three types of distributed locks:1. Database optimistic lock; 2. Redis-based distributed locks; 3. Zookeeper-based distributed locks . this blog will introduce the second way to implement distributed locks based on Redis. Although there are a variety of blogs on the web that introduce the impl

of shared and exclusive locks sometimes deadlock phenomenon, and the use of update locks can avoid the occurrence of deadlocks. A resource's update lock can only be assigned to one transaction at a time, and if the resource needs to be modified, the update lock becomes an exclusive lock, or it becomes a shared lock. Intent Lock: SQL Server needs to acquire shared l