drm lock

Alibabacloud.com offers a wide variety of articles about drm lock, easily find your drm lock information here online.

MySQL shared lock-exclusive lock

Turn InnoDB row-level locksInnoDB Row-level locksCategory: Database 2013-03-13 16:40 1745 people read comments (0) favorite reports Nnodb lock mode and lock methodInnoDB implements the following two types of row locks.? Shared Lock (S): Allows a transaction to read one line, preventing other transactions from acquiring an exclusive

MySQL lock usage-row-Level Lock

MySQL lock usage-row-Level Lock is the smallest lock in MySQL, which can greatly reduce database operation conflicts. However, the smaller the granularity, the higher the implementation cost. The MYISAM engine only supports table-level locks, while the INNODB Engine supports row-level locks. The following content is also for INNODB row-level locks. Row-level lock

Oracle table-level Lock (TM Lock)

Suppose a user (assuming a) issues the following statement to update a record: Sql> Update Employees set last_name= ' Hansijie ' where employee_id=100; Example above, at which point a user has issued an SQL statement that updates the record for employee_id 100. When a has not yet been submitted, another user D issues the following statement: sql> drop table employees; Because user A has not committed a transaction yet, the transaction has not ended, and other users cannot delete the table,

Optimistic lock and pessimistic lock

The comparison between optimistic lock and pessimistic lock: Category Realize Characteristics Risk Pessimistic lock Rely on the lock mechanism of database layer Exclusive Nature The large overhead of database performance is often unsustainable, especially for

Java Multithreading Series--"Juc lock" 04 Fair Lock (II)

Tag: Code member jdk1.7 read illegal boolean return port OwnerRelease Fair Lock (based on jdk1.7.0_40)1. Unlock ()Unlock () implemented in Reentrantlock.java, the source code is as follows: Public void unlock () { sync.release (1);}Description :Unlock () is an unlock function, which is implemented by Aqs's release () function.Here, the meaning of "1" is the same as the "Get Lock function acquire (1)", wh

Why does the database need a lock mechanism? What are the lock mechanisms? __ Database

"Why do you want to lock?" A database is a shared resource that is used by a multi-user, such as a user table T_user, two people in front of the browser login to the same account, the phone number changed. When multiple users have concurrent access to the data, multiple transactions are generated in the database while the same data is being accessed. If the concurrency operation is not controlled, it may read and store incorrect data, destroy the cons

Learn about update lock (U) and exclusive lock (X)

have not been seriously understood UPDATE operation of the lock, recently in MSDN Forums See a problem, ask the heap table update deadlock problem, the problem is very simple, there are similar tables and data: CREATE TABLE DBO.TB ( C1 int, C2 char (Ten), c3 varchar) ; GO DECLARE @id int; SET @id = 0; While @id In query one, perform the update operation: BEGIN TRAN UPDATE dbo.tb SET c2 = ' xx ' WHERE c1 = 2; WAITFOR DELAY ' 00:00:30

Mysql lock mechanism usage summary, mysql Lock Mechanism

Mysql lock mechanism usage summary, mysql Lock Mechanism 1. isolation level (1) Read uncommitted (RU) At this isolation level, transactions are completely isolated and dirty reads are generated. uncommitted records can be read, which is not used in actual cases. (2) Read committed (RC) Only committed records can be read. At this isolation level, phantom read occurs. Phantom read refers to executing the same

Java concurrent Programming--abstractqueuedsynchronizer lock and Lock Analysis (ii) __java

There are many implementation classes of lock in the Java.util.concurrent.locks package, commonly used in Reentrantlock, Readwritelock (Implementation class Reentrantreadwritelock), Its realization all relies on Java.util.concurrent.AbstractQueuedSynchronizer class, realizes the idea to be similar, therefore we take reentrantlock as the explanation cut-in point. 1. Reentrantlock's call Process After observation Reentrantlock all

MySQL lock mechanism and PHP lock mechanism

Tags: handle dirty \ n Client pre Opera read data reporting requestThe lock in MySQL:Grammar:LOCK Table table Name 1 read| WRITE, table name 2 read| WRITE ... "Lock-up table" ... "..".UNLOCK TABLES "Release table"READ: Reading Lock | Shared Lock: All clients can only read this table and cannot write this tableWrite:

A murder caused by a lock-free message queue: How to be a real programmer? (b)--month: Spin lock

Previous continuedA murder caused by a lock-free message queue: How to be a real programmer? (a)--ground: CauseA murder caused by a lock-free message queue: How to be a real programmer? (b)--month: Spin lockParallel spaceIn the copy of the above line I stopped first, is considered to occupy a position, although I know how to write, but the feeling is still very messy.I suddenly thought, since so tangled, so

Display lock Reentrantlock and read-write lock for multi-threaded concurrent programming

Prior to Java5.0, only synchronized (built-in lock) and volatile. The display lock Reentrantlock is introduced after Java5.0. Reentrantlock OverviewThe Reentrantlock is a reentrant lock, which differs from the built-in lock, which needs to display the lock and unlock fo

Java Multithreading: "Juc lock" 03 of the Fair Lock (i)

Basic concepts In this chapter, we will explain the principle of "thread gain fair lock", and we need to understand several basic concepts before we explain it. The following are all based on these concepts; These concepts may be tedious, but from these concepts it is possible to glimpse some of the architecture of the "Java Lock", which is helpful in understanding the

Oracle lock 1: DML lock

Oracle lock 1: DML lockDML lock, also known as data lock, is used to ensure data integrity when multiple users operate on data. DML lock prevents conflicting DML and DDL operations at the same time. DML Locks include Row Locks (TX) and Table Locks (TM). Different DML operations will automatically request the correspond

Semaphores mutex lock spin lock atomic operation

This article from: http://blog.163.com/hbu_lijian/blog/static/126129153201261722410353/ Kernel synchronization measures (for Linux kernel) To avoid concurrency and prevent competition. The kernel provides a set of Synchronization Methods to protect shared data. Our focus is not to introduce the detailed usage of these methods, but to emphasize the difference between these methods and them.The synchronization mechanism used in Linux has been continuously improved since 2.0 to 2.6. From the initia

A bloodcase caused by a lock-free Message Queue: how to be a real programmer? (2) -- month: spin lock, queue spin

A bloodcase caused by a lock-free Message Queue: how to be a real programmer? (2) -- month: spin lock, queue spinPrefix A bloodcase caused by a lock-free Message Queue: how to be a real programmer? (1) -- location: Cause A bloodcase caused by a lock-free Message Queue: how to be a real programmer? (2) -- month: spin lo

Redis Lock Structure and redis lock

Redis Lock Structure and redis lockSingle thread and isolation Redis uses a single thread to execute transactions. transactions are run in a serial manner. That is to say, the execution of a single command in Redis and the execution of a transaction are thread-safe and will not affect each other, isolation. In multi-threaded programming, be careful when accessing shared resources: import threadingnum = 1lock = threading.Lock()def change_num(): glob

Lock _rac environment killed status after Kill lock table session (resolved)

Original works, from "Deep Blue Blog" blog, dark blue blog:http://blog.csdn.net/huangyanlong/article/details/46876961RAC Production library kill lock table session killed state processing occursEnvironment:Operating system: CentOS 6.4 64BITDatabase: Oracle RAC 11.2.0.4 R2 64bitIn a project, when you perform a big data extraction task, the extraction error occurs and the large table needs to be re-extracted. The insert operation is canceled and then th

Android Black Technology Series-modified lock screen password and malicious lock machine Sample principle Analysis

first, the encryption algorithm in AndroidThe previous article has introduced the Android System lock screen cipher algorithm principle, here to summarize said:The first type: input cipher algorithmEnter the plaintext password + The salt value of the device, then manipulate MD5 and SHA1 after the conversion to hex value for stitching, the final encryption information is saved to the local directory:/data/system/password.keyThe second type: gesture cip

Analysis of inter-thread communication two: read-write lock and Spin lock

The above discusses the mutex and conditional variables used for thread synchronization, this article will discuss the use of read and write locks and spin locks , and give the corresponding code and considerations, the relevant code can also be downloaded on my GitHub . read/write lock The mutex is either locked or unlocked, and only one thread can lock it at a time, while a read-write

Total Pages: 15 1 .... 9 10 11 12 13 .... 15 Go to: Go

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

not found

404! Not Found!

Sorry, you’ve landed on an unexplored planet!

Return Home
phone Contact Us
not found

404! Not Found!

Sorry, you’ve landed on an unexplored planet!

Return Home
phone Contact Us

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.