typewell

The evolution of a class method for quickly creating objects:Original version:+ (Book *) book {return [[[Book Alloc] init] autorelease];}Evolutionary version:+ (ID) book {return [[[Self alloc] init] autorelease];}Evolution version Two:+ (instancetype) book {return [[[Self alloc] init] autorelease];The evolutionary version is better than the original version, it is in the subclass of the method of the parent class, the return is the subclass itself, not the original version of the parent class ca

　　types of data supported in PHP8 Types of data are supported in php . and A form of pseudo-type in 3. 8 Types of data are divided into the following 3 major categories, the first one is our scalar type, scalar type it can only store a single data, the second class is our composite type, the third is a special type, Divided into these three categories, that first we come to a category of the view. In the first class, the scalar type is divided into the following four small classes, the first o

, independent host users please contact the server administrator to optimize the configuration of MySQL server, can refer to:Modify the parameters in the MySQL configuration file (under Windows My.ini, Linux for my.cnf): CODE: [COPY] max_connections = + Wait_timeout = 5 If you do not have the ability to add, modify and restart MySQL, if you regularly report this error, please follow the server Environment Setup tutorial Check your server4. Parameters in the MySQL statement

eventually results in the entire system reaching a certain threshold and the performance is rapidly declining.1000~2000qps--fork/select, lock mode limit typeWell, in a word: The threading model determines throughput. The file system access lock is a disaster at this level, no matter what lock is the most common lock in your system. This requires the system can not exist in the central node, all the data must be distributed storage, the data needs to

entire system reaching a certain threshold and the performance is rapidly declining.1000~2000qps--fork/select, lock mode limit typeWell, in a word: The threading model determines throughput. The file system access lock is a disaster at this level, no matter what lock is the most common lock in your system. This requires the system can not exist in the central node, all the data must be distributed storage, the data needs to be distributed processing.

DB layer, which eventually led to the entire system to achieve a certain threshold, performance quickly decline. 1000~2000qps--fork/select, lock mode limit typeWell, in a word: The threading model determines throughput. Regardless of what locks are most common in your system, file system access locks are a disaster at this level. This requires that the system can not exist in the central node, all the data must be distributed storage, data needs to b