PHP Pthreads-使用mysqli

我第一次尝试在我的web应用程序中使用pthreads。我使用pthreads处理简单的测试用例，但在pthreads中使用mysql查询时遇到了问题。这是我的php文件：

class SqlThread extends Thread
{
    private $dbc;
    public $log;
    public $return;

    public function __construct(){
        $this->dbc = mysqli_connect("localhost", "root", "rootpassword", "my_database");

        $this->log = "<br>(".__LINE__.") construct finished.";
    }

    //gets called when thread is started
    public function run(){
        $val = $this->testSqlCall();

        $this->log .= "<br>(".__LINE__.") testSqlCall() has finished";

        $this->return = $val;
    }

    /**
     * testing sql queries
     */
    function testSqlCall(){

        $sql = "SELECT *
                FROM client_detail";

        $this->log .= "<br>(".__LINE__.") testSqlCall() - sql: ".$sql;

        $r= @mysqli_query($this->dbc,$sql);
        $num = mysqli_affected_rows($this->dbc);

        $this->log .= "<br>(".__LINE__.") testSqlCall() - total number of returned rows: ".$num;

        return $num;

    }
}

/**
 * threaded test
 */
$thread = new SqlThread();
$thread->start();
$thread->join();

echo "<br><br><br>thread return value:";
var_dump($thread->return);
echo $thread->log;

/**
 * same test, but not threaded
 */

$dbc = mysqli_connect("localhost", "root", "rootpassword", "my_database");
$sql = "SELECT *
        FROM client_detail";
$r = @mysqli_query($dbc,$sql);
$num = mysqli_affected_rows($dbc);
echo "<br><br> --- non-threaded return value: $num";

如您所见，SqlThread内的mysqli查询不返回任何内容，而SqlThread类外的完全相同的查询返回我所期望的内容

---

有什么想法吗？有人在php线程中使用sql查询吗？

问题是mysqli对象不适合在多个线程中使用，您希望为启动的每个线程创建一个mysqli实例，因此每个线程都有一个唯一的连接

<?php
define("SQLHOST", "localhost");
define("SQLUSER", "root");
define("SQLPASS", "");
define("SQLDB",   "test");
define("SQLPORT", 3306);
define("SQLSOCK", "/var/lib/mysql/mysql.sock");

class Mine extends Thread {
    public function run() {
        try {
            $my = new mysqli(SQLHOST, SQLUSER, SQLPASS, SQLDB, SQLPORT, SQLSOCK);
            if ($my) {
                $result = $my->query("SHOW DATABASES;");

                if (is_object($result)) {
                    while (($row = $result->fetch_assoc())) {
                        var_dump($row);
                    }
                }
            }
        } catch(Exception $ex) {
            var_dump($ex);
        }
    }
}

$mine = new Mine();
$mine->start();
?>

请注意，MySQLi对象永远不会存储在Threads对象范围内，因为您应该只在对象范围内存储要共享的内容，并且由于您无法共享MySQLi连接，因此最好在方法范围内对其进行操作

github上有许多示例，包括一个SQLWorker示例，您应该全部阅读

---

进一步阅读：

您需要在线程内部建立连接。在外部实例化它将使每个线程使用相同的连接，这是不推荐的，如果没有错误的话，在任何多线程体系结构中也是如此。我第一次发现这一点是在用Python进行多线程数据库查询时。

<?php
define("SQLHOST", "localhost");
define("SQLUSER", "root");
define("SQLPASS", "");
define("SQLDB",   "test");
define("SQLPORT", 3306);
define("SQLSOCK", "/var/lib/mysql/mysql.sock");

class Mine extends Thread {
    public function run() {
        try {
            $my = new mysqli(SQLHOST, SQLUSER, SQLPASS, SQLDB, SQLPORT, SQLSOCK);
            if ($my) {
                $result = $my->query("SHOW DATABASES;");

                if (is_object($result)) {
                    while (($row = $result->fetch_assoc())) {
                        var_dump($row);
                    }
                }
            }
        } catch(Exception $ex) {
            var_dump($ex);
        }
    }
}

$mine = new Mine();
$mine->start();
?>

array(1) {
  ["Database"]=>
  string(18) "information_schema"
}
array(1) {
  ["Database"]=>
  string(5) "mysql"
}
array(1) {
  ["Database"]=>
  string(18) "performance_schema"
}
array(1) {
  ["Database"]=>
  string(4) "test"
}