transaction and concurrency control

, into the payment link, see who deft on hand, at this time less people, plus lock what is simple.Scenario three, if it is a single server, you can use the memcache lock to achieveProduct_key Key for the ticketProduct_lock_key for Ticket lock keyWhen Product_key is present in memcached, all users can enter the order process.When entering the payment process, first store add (Product_lock_key, "1″") to memcached,If the return succeeds, enter the payment process.If not, it means that someone has e

mod_limitipconn-0.24.tar.bz2Cd mod_limitipconn-0.24/Usr/local/apache2/bin/apxs-c-I mod_limitipconn.cEdit httpd. confExtendedStatus OnLoadModule limitipconn_module modules/mod_limitipconn.soMaxConnPerIP 5 # maximum concurrency of 5NoIPLimit image/* # no restrictions on imagesMaxConnPerIP 2 # maximum concurrency of 2To limit the number of concurrent ip connections to a VM, modify the extra/httpd-vhost.conf t

addition to the mainstream relational database management systems such as SQL Server,oracle and DB2 provide transactional support, transactional data manipulation can also be applied to other data storage resources, such as MSMQ. Since Windows Vista began to incorporate the file system (NTFS) to the registry into the category of transactional resources (transactional Resource). Ii. explicit control of transactions Although there are more and more f

atomic variable, assigned a value of 1*/ Static intXxx_open (structInode *inode,structFile *Filp) { ... if(!atomic_dec_and_test (xxx_available))/*A test value of 0 returns true otherwise false*/{atomic_inc (xxx_available); return-Ebusy;/*has been opened*/ } ... return 0;/*Success*/ } Static intXxx_release (structInode *inode,structFile *Filp) {Atomic_inc (xxx_available);/*releasing the device*/ return 0; }Spin lockspinlock_t lock; /* Definition */Spin_lock_init (

go home. This demand has just avoided the danger of leaving some children in school, especially in kindergartens or primary school students ~~ Package com. zhy. concurrency. cyclic; import java. util. concurrent. brokenBarrierException; import java. util. concurrent. cyclicBarrier;/*** Secure Access Control System ** @ author zhy **/public class CyclicBarrierTest {/*** Total number of students */private f

In order to prevent users from repeatedly clicking on the page or initiating multiple requests at the same time, request processing requires the operation of the Redis cache, which requires concurrent lock control of the concurrency boundary to realize the idea:Since the token of each page's request is unique, token can be used as the lock (key) and the current time as value for concurrent lock

In this paper, we introduce the different configuration methods of the session management and concurrency control of Spring security in four different situations, as well as the result.(1) First, you write session_error.jsp page, for displaying Session related error message. The error message is passed in through the page parameter ID . P > Session error:${param.id}p>p>${spring_ Security_last_exception.mes

Many projects, especially web projects, basically use frameworks such as struts1, struts2., spring, hibernate, springmvc, and ibatise to improve development efficiency. In terms of transaction processing, spring is particularly prominent. It encapsulates transactions well. With the configuration of AOP, You can flexibly configure the transaction on any layer. However, in many cases, it is necessary to direc

"Xiao Tao, how many other things do you think I was joking about train tickets, plane tickets, and Mm? You are dancing in front of your eyes, and you are not finishing the dance ..." "Ah? How can this problem be solved? In a dormitory, the difference between people is so big. I don't study well at ordinary times. If I have any questions, I will give you free teaching and complain, too many friends .... "I hammer the table and say. "My friends, I'm not enough friends. Haven't you heard of me?

Document directory 1.1 Definition 1.2 operation functions 1.3 Reader/writer flag Semaphore and mutex for Linux driver Learning In the driver, when multiple threads simultaneously access the same resource (global variables or hardware resources), it may lead to a race. Therefore, we must control the concurrency of shared resources. The most common methods to solve

In an Apache system, the concurrency in Linux is not very high, and it looks like 3 K (in fact, the HTTP request may only be 300/s). Common servers may encounter problems to varying degrees. the concurrency control of Apache is mainly controlled by one of prefork and worker. we can use httpd-L to determine whether the currently used MPM is prefork. c, or worker.

Four concurrency control mechanisms: Atomic operations, spin locks, semaphores, and completion quantities.Atomic variable operationAtomic variable operations are never interrupted by any other task or event until they are executed. Atomic operations require hardware support and are therefore schema-dependent, and their API and atomic type definitions are defined in the Include/asm/atomic.h file in the kerne

The concept of concurrency control----concurrency refers to the parallel execution of multiple execution units, while concurrent execution units share resources (hardware resources andAccess to global variables, static variables, and so on,----software, can easily lead to race.What happens in a race----Multiple CPUs with symmetric multiprocessor (SMP)----A single

Continue the Concurrency topic ~This introduction Cyclicbarrier: Take a look at the API gaze:/** * A synchronization aid that allows a set of threads to all wait for * each other to reach A common barrier point. cyclicbarriers is * useful in programs involving a fixed sized party of threads it * must occasionally wait for each o Ther. The barrier is called * A synchronous helper class that allows a group of threads to block to a location at th

++; System.out.println (Thread.CurrentThread (). GetId () + ": I is" + i); Thread.Sleep (3000); catch (Exception e) {System.out.println (E.getmessage ()); finally {Lock.unlock (); } public static void Main (string[] args) {Executorservice exEcutorservice = Executors.newfixedthreadpool (3); Threadwithreentrantlock thread = new Threadwithreentrantlock (); for (int i=0; i Run Result: You can see that thread 111 holds

all forwarded to a payment server, into the payment link, see who deft on hand, at this time less people, plus lock what is simple. scenario Three, if it is a single server, you can use the Memcache lock to achieve Product_key key for the ticket Product_lock_key for ticket lock key when Product_key is present in memcached, all users can enter the order process. when entering the payment process, first store add (Product_lock_key, "1″") to Memcached, If the return succeeds, enter the p

, into the payment link, see who deft on hand, at this time less people, plus lock what is simple.Scenario three, if it is a single server, you can use the memcache lock to achieveProduct_key Key for the ticketProduct_lock_key for Ticket lock keyWhen Product_key is present in memcached, all users can enter the order process.When entering the payment process, first store add (Product_lock_key, "1″") to memcached,If the return succeeds, enter the payment process.If not, it means that someone has e

/*************************************** ******************************/Master/Slave table transaction control solution EJB3.0Author: chinayaosirQQ: 44633197 QQ Group: 8284865,000048Blog http://blog.csdn.net/chinayaosir 0. Transaction Consistency Control explanation:Bank Card transfer operation transactions:The user tr

Php + mysqli transaction control for bank transfer instances. Php + mysqli transaction control implement bank transfer instance this article mainly introduces php + mysqli transaction control implement bank transfer, the example a

with her. Let's buy a ticket together at, so we have a ticket for each conductor on both sides, the two of us can be together. "Xiao Wang smiled. "Stupid, I sprayed a salt water on you, and I had a ticket. You two went to two different ticket sites at the same time to buy it. It was still a ticket, how could it be said that I went to two different places and both the conductor saw a ticket, and then sold the only one to both of you at the same time? "I interrupted. "Forget it, look at the ide