欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页  >  php教程

php持久化连接数据库

程序员文章站 2022-05-31 10:13:32
...

php的持久化数据库连接已经不是一个新鲜的名词了,由于php语言生命周期的问题,如果每次连接数据库都重新打开一个连接会很低效,所以引入了长连接机制(应该是实现在sapi部分,例如cli sapi就不支持db长连接),本文探究apache2handler sapi和 fpm sapi是否支持db长

php的持久化数据库连接已经不是一个新鲜的名词了,由于php语言生命周期的问题,如果每次连接数据库都重新打开一个连接会很低效,所以引入了长连接机制(应该是实现在sapi部分,例如cli sapi就不支持db长连接),本文探究apache2handler sapi和 fpm sapi是否支持db长连接.使用方法以pdo为例在实例化pdo对象时传入:

PDO::ATTR_PERSISTENT => true

即可实现长连接,但是隐约在哪里听说过在apache下由于是以线程的方式执行,所以连接在线程关闭时也会释放掉.本着实践是检验真理的唯一标准态度,遂决定做个实验测试下.

测试环境:
mysql-5.1.50
php-5.4.19
apache && nginx

php测试代码:

 PDO::FETCH_ASSOC,
        PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8',
        //PDO::ATTR_PERSISTENT => true #pdo默认为false
    )
);

var_dump($pdo->query('select now()')->fetchColumn());

测试php-fpm sapi(nginx):
首先查看数据库连接:

mysql> show full processlist;
+----+------+-----------------+------+---------+------+-------+-----------------------+
| Id | User | Host            | db   | Command | Time | State | Info                  |
+----+------+-----------------+------+---------+------+-------+-----------------------+
|  1 | root | localhost:61513 | test | Query   |    0 | NULL  | show full processlist |
+----+------+-----------------+------+---------+------+-------+-----------------------+
1 row in set (0.00 sec)

访问php测试脚本后查看数据库连接:

mysql> show full processlist;
+----+------+-----------------+------+---------+------+-------+-----------------------+
| Id | User | Host            | db   | Command | Time | State | Info                  |
+----+------+-----------------+------+---------+------+-------+-----------------------+
|  1 | root | localhost:61513 | test | Query   |    0 | NULL  | show full processlist |
+----+------+-----------------+------+---------+------+-------+-----------------------+
1 row in set (0.00 sec)

将测试脚本中PDO::ATTR_PERSISTENT => true的注释取消掉后执行脚本,再查看数据库连接:

mysql> show full processlist;
+----+------+-----------------+------+---------+------+-------+-----------------------+
| Id | User | Host            | db   | Command | Time | State | Info                  |
+----+------+-----------------+------+---------+------+-------+-----------------------+
|  1 | root | localhost:61513 | test | Query   |    0 | NULL  | show full processlist |
|  3 | test | localhost:61525 | test | Sleep   |    2 |       | NULL                  |
+----+------+-----------------+------+---------+------+-------+-----------------------+
2 rows in set (0.00 sec)

结论1:fpm sapi支持db长连接

测试apache2handler sapi(apache):
首先关闭掉长连接会话:

mysql> kill 3;
Query OK, 0 rows affected (0.00 sec)

查看数据库会话列表:

mysql> show full processlist;
+----+------+-----------------+------+---------+------+-------+-----------------------+
| Id | User | Host            | db   | Command | Time | State | Info                  |
+----+------+-----------------+------+---------+------+-------+-----------------------+
|  1 | root | localhost:61513 | test | Query   |    0 | NULL  | show full processlist |
+----+------+-----------------+------+---------+------+-------+-----------------------+
1 row in set (0.00 sec)

执行测试脚本(注释掉PDO::ATTR_PERSISTENT => true,即未设置长连接的脚本)并查看数据库会话:

mysql> show full processlist;
+----+------+-----------------+------+---------+------+-------+-----------------------+
| Id | User | Host            | db   | Command | Time | State | Info                  |
+----+------+-----------------+------+---------+------+-------+-----------------------+
|  1 | root | localhost:61513 | test | Query   |    0 | NULL  | show full processlist |
+----+------+-----------------+------+---------+------+-------+-----------------------+
1 row in set (0.00 sec)

然后执行设置好长连接的脚本并查看数据库会话:

mysql> show full processlist;
+----+------+-----------------+------+---------+------+-------+-----------------------+
| Id | User | Host            | db   | Command | Time | State | Info                  |
+----+------+-----------------+------+---------+------+-------+-----------------------+
|  1 | root | localhost:61513 | test | Query   |    0 | NULL  | show full processlist |
|  5 | test | localhost:61569 | test | Sleep   |    2 |       | NULL                  |
+----+------+-----------------+------+---------+------+-------+-----------------------+
2 rows in set (0.00 sec)

结论2:apache2handler sapi也是支持db长连接的