check condition

from:http://blog.csdn.net/fengge8ylf/article/details/6896380 Author: Wang Dong 1.1 What is conditional variable and condition wait. To put it simply: A condition variable (condition variable) is a mechanism for synchronizing with global variables

Introduction: The related functions are as follows:1 int pthread_cond_init (pthread_cond_t * cond, pthread_condattr_t * cond_attr );2 int pthread_cond_wait (pthread_cond_t * cond, pthread_mutex_t * mutex );3 int pthread_cond_timewait (pthread_cond_t

MYSQL5.6.7-RC index condition pushdown indexed condition Push code interpretationHttp://jishu.zol.com.cn/4505.htmlMYSQL5.6.7-RC Index Condition pushdown code interpretation a-a+2013-08-07 11:10|Share to:Interested in the index condition Pushdown,

1. Description of the problemHow does a SQL work in a database? I believe a lot of people will be interested in this problem. Of course, to fully describe a SQL in the database life cycle, this is a very big problem, covering the SQL lexical parsing,

Source: Drill down into the MySQL kernel1 Problem DescriptionHow does a SQL work in a database? I believe a lot of people will be interested in this problem. Of course, to fully describe a SQL in the database life cycle, this is a very big problem,

Reprint Please specify source: http://blog.csdn.net/suool/article/details/38582521.Basic concepts and principlesMutexes can resolve mutually exclusive access to resources, but in some cases, mutual exclusion does not solve the problem, such as two

1. There is a problem with the mutex: mutexes are the necessary tools for threaded threads, but they are not omnipotent. For example, what happens if a thread is waiting for a condition in the shared data to appear? It can repeatedly lock and unlock

ICP Technology is an index optimization technique introduced in MySQL5.6. It reduces the number of back tables when using the two-level index to filter where conditions and reduces the number of interactions between the MySQL server layer and the

1. A question describes how an SQL statement is executed in a database? I believe many people will be interested in this issue. Of course, it is a huge problem to fully describe the lifecycle of an SQL statement in the database, it covers a series

1, problem descriptionHow does a SQL work in a database? I believe a lot of people will be interested in this problem. Of course, to fully describe a SQL in the database life cycle, this is a very big problem, covering the SQL lexical parsing,