stack on lock

pessimistic lock, optimistic lock, only applicable to update operation In the actual production environment, if the concurrency is not small, can use pessimistic locking method, this method is very convenient and simple to use.However, if the concurrency of the system is very large, pessimistic locking can lead to very large performance problems, so choose optimistic locking method. Pessimistic locking ass

Shared lock "s lock"Also called a read lock, if the transaction T with the data object a plus s lock, then the transaction T can read a but cannot modify a, the other transaction can only a plus s lock, and cannot add x lock, unti

The exclusive lock is also called the Write lock ((eXclusive lock, précis-writers is the x lock), if the transaction T to the data object a plus x lock, then only allow T to read and modify a, no other transaction can be a plus any type of

shared lock (S lock) and exclusive lock (x Lock) Category: Database 2008-11-07 10:53 4409 people read reviews (2) favorite report Shared lock "s lock"Also called a read lock, if the t

Java synchronized keyword usage and level of Lock: Method Lock, Object lock, Class lock Reproduced from: http://blog.csdn.net/le_le_name/article/details/52348314 Java built-in locks: Each Java object can be used as a lock that implements synchronization, and these locks be

Example of the stack data structure implemented by PHP [stack entry, stack exit, and stack traversal] and data structure example This example describes the stack data structure implemented by PHP. We will share this with you for your reference. The details are as follows: Us

Shared lock "s lock"Also called a read lock, if the transaction T with the data object a plus s lock, then the transaction T can read a but cannot modify a, the other transaction can only a plus s lock, and cannot add x lock, unti

1. Features:The thread that has acquired the lock requests the lock again, which can be obtained directly.2. Realize:Custom internal class Sync, inheriting Abstarctqueuedsynchronizer:2.1. Get lock : Lock ()A, Fair lock:Acquire (1)B, non-fair lock:if (compareandsetstate (0, 1))CAS, the current state is 0, the current th

Original link: http://www.cnblogs.com/laoyangHJ/archive/2011/08/17/gc-Stack.htmlDrill down into Java Virtual machines: stacks and heap in the JVMIn the JVM, memory is divided into two parts, stack (stack) and heap (heap), where we know the stack and heap from the perspective of the memory management principle of the JVM, and these principles recognize the problem

One: Write an algorithm that arranges the elements in the stack in ascending order. The implementation of the stack is unknown, the algorithm can only be completed by the stack, the function can be used to push, pop, top, empty and so on.Idea: You can use a different stack to do the sorting.1, from the original

) if the lock does not exist, create a lock and insert the lock object into the hash linked list. C) If yes, determine whether the transaction has a stronger lock (lock_rec_has_expl) D) If yes, jump to 5. If not, jump to 6 (lock_rec_lock_slow) E) set the bit according to heap_no on the page. F) Determine whether the re

In the computer field, stack is a concept that cannot be ignored. The C language programs we write are basically used. But for many beginners, stack is a very vague concept. STACK: a data structure, a place to store when the program is running, which may be a recognition of many beginners, because I used to think so and confuse the word

page level: Engine BDB. Table level: Engine MyISAM, understood to lock the entire table, you can read at the same time, write No Line level: Engine INNODB, a separate row of record lock table level, directly lock the entire table, during your lock, other processes cannot write to the table. If you are a write

Reentrantlock is a reentrant lock that can support a thread to repeatedly lock resources, and he also supports fair locking and unequal locking. The Synchronized keyword also implicitly supports re-enter, such as a recursive method of synchronized modification, when the method executes, The execution thread can still obtain the lock multiple times after acquiring

Tags: memory load Attach description spec buffer add Content list pictureWrite-C + + programs are most afraid of the emergence of such a hint, fortunately, in the debugging environment displayed, in the non-debug state of the direct crash exit.From the above assembly code found in the memory address eax+38h the value of error, which means that the address is illegal Bai, can not access, is generally accessed by the null pointer.The direct call to the Qlist::append () method also makes an error,

Original link: http://www.jb51.net/article/50047.htmPage level: Engine BDB.Table level: Engine MyISAM, understood to lock the entire table, can read at the same time, write NoRow level: Engine INNODB, single row of records plus lockTable level, which locks the entire table directly, and other processes cannot write to the table during your lock. If you are writing a loc