When MySQL performs a large number of operations, it reports that the database cannot be connected to the error

problem: when MySQL performs a large number of socialize operations, the report fails to connect to the database, error details are as follows:

Fatal error:uncaught exception ' pdoexception ' with message ' sqlstate[hy000] [2003] Can ' t connect to MySQL server on ' 127. 0.0.1 ' In/mnt/change/www/html/data/conn.php:5 Stack trace: #0/mnt/change/www/html/data/conn.php (5): pdo->__ Construct (' mysql:host=127 ... ', ' aaa ', ' AAA ') #1/mnt/change/www/html/data/conn.php: Conn () #2/mnt/change/www/ html/test/zb/addhdg.php: Sql_query (' Select Loopdata ... ') #3 {main} thrown in/mnt/change/www/html/data/conn.php on Line 5

operating Environment:Linux+apache+php+mysql

Reason: Yes when MySQL executes the operation, need to connect the database, the connection is required to occupy the port, a large number of queries to run out of ports, the database will not be able to connect

See why:

When performing a large number of MySQL connections, execute in linux

Netstat-nt

You 'll see a lot of connections. time_out Status

Solutions

Step one: Optimize MySQL and close the MySQL connection immediately after you get the data

(1)PDO only needs to set the connection to null

$pdo =new PDO ("Mysql:host=127.0.0.1;dbname=aaa", "AAA", "AAA"), and/or execute the following statement to $pdo=null after getting the data;

Step Two: Optimize your Linux system

(1) write the following statement in the /etc/sysctl.cnf

Net.ipv4.tcp_fin_timeout = 2net.ipv4.tcp_tw_recycle = 1net.ipv4.tcp_tw_reuse = 1

Explain:

Net.ipv4.tcp_tw_recycle=1 is to turn on fast time-wait sockets Recovery, that is, to quickly reclaim the connection in time-wait , The default value is 0, which is the off state

Net.ipv4.tcp_fin_timeout : Set the connection time-out, in seconds, the default value is

Net.ipv4.tcp_tw_reuse =1: Allows the re-application of sockets in the time-wait State for new TCP Connection, the default value is 0, which is the off state

(2) execute in linux

Sysctl-p

Make the above configuration effective

This article is from the "Technology" blog, so be sure to keep this source http://heyu1.blog.51cto.com/13158032/1956343

When MySQL performs a large number of operations, it reports that the database cannot be connected to the error