PHP PDO为SELECT FOUND_ROWS()返回不一致的结果 [英] PHP PDO returning inconsistent results for SELECT FOUND_ROWS()

问题描述

我在使用PHP/PDO和MySQL时遇到问题

I have an issue with PHP/PDO and MySQL

当我使用SQL_CALC_FOUND_ROWS运行查询然后选择FOUND_ROWS()时，80％的时间返回0，其余时间FOUND_ROWS是准确的

When I run a query with SQL_CALC_FOUND_ROWS and then select FOUND_ROWS(), 80% of the time its returning 0, and the rest of the time FOUND_ROWS is accurate

我已经将其简化为一个简单的测试循环，但这在我的开发服务器上可以正常工作，但是在生产中，测试用例存在不一致问题.

I've reduced it to a simple test loop, but this works fine on my dev server, but in production the test case is having the inconsistency problem.

即使在生产环境中，从MySQL命令行运行相同的查询也可以正常工作，因此这似乎是PHP/PDO问题

Running the same queries from MySQL command line works correctly even in production, so it appears to be a PHP/PDO problem

PHP 5.5.28-使用mysqlnd 5.0.11-dev CentOS 6.6(最终版)上的Percona Server 5.6.25-73.1-日志

PHP 5.5.28 - using mysqlnd 5.0.11-dev Percona Server 5.6.25-73.1-log on CentOS 6.6 (Final)

任何人都可以帮忙吗?我已经尽力想了一切，然后把头发拔掉了

Can anyone help please? I've tried everything I can think of, and I'm tearing my hair out

<?php
require_once "../consts.php";

$nolimit_query = "select SQL_CALC_FOUND_ROWS targetusers.u_id
  FROM 
    users targetusers 
    LEFT JOIN user_extra targetuserextra ON (targetuserextra.ue_userid = targetusers.u_id) 
    LEFT JOIN countries ON (c_id = targetusers.u_country) 
    LEFT JOIN cities ON (cities.ct_countryid = c_id and cities.ct_id = targetusers.u_city) 
    LEFT JOIN userimages ON (targetusers.u_primaryimage = userimages.ui_id and userimages.ui_userid = targetusers.u_id and userimages.ui_imagetype = 'P') 
  WHERE 
    (targetusers.u_deleted = 0) and 
    (targetusers.u_id NOT IN (19, 32, 115)) and 
    (targetusers.u_active = 1) and 
    (targetusers.u_confirmed=5) order by u_lastupdated DESC LIMIT 10, 10";

// already tried this soln suggested elsewhere -- defaults to off for my PHP anyway though
ini_set("mysql.trace_mode", 0);
ini_set("display_errors", 1);

// set up PDO connection
$dbh = new PDO(
    "mysql:host=" . Config::Get()->DB_SERVER . ";dbname=" . Config::Get()->DATABASE_NAME . ";charset=utf8", 
    Config::Get()->DB_USERNAME, 
    Config::Get()->DB_PASSWORD
);
$dbh->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);
$dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$dbh->setAttribute(PDO::ATTR_PERSISTENT, false);

echo $dbh->getAttribute(PDO::ATTR_CLIENT_VERSION) . "<br>";
echo $dbh->getAttribute(PDO::ATTR_DRIVER_NAME) . "<br>";
echo $dbh->getAttribute(PDO::ATTR_SERVER_INFO) . "<br>";
echo $dbh->getAttribute(PDO::ATTR_SERVER_VERSION) . "<br><br>";

echo date("r") . "<br>";
for ($i=0; $i<5; $i++)
{
    // run query above
    $stmt = $dbh->prepare($nolimit_query);
    if ($stmt === FALSE)
    {
        die($stmt->errorInfo());
    }

    // get result set 
    if (($result = $stmt->execute()) === TRUE)
    {
        $a = $stmt->fetchAll(PDO::FETCH_ASSOC);
        $stmt->closeCursor();
        $stmt = NULL;

        // this query returns inconsistent results (80% of the time it returns 0!)
        $b = $dbh->query("SELECT FOUND_ROWS() as cnt")->fetch(PDO::FETCH_ASSOC);
        echo "FOUND ROWS = " . $b["cnt"] . "<br>";      
    }
}

此脚本的输出如下.

请注意，在5个循环中，只有2个返回了FOUND_ROWS的正确值，其他3个返回为0

Note that only 2 of the 5 loops are returning the correct value for FOUND_ROWS, with the other 3 coming back as 0

mysqlnd 5.0.11-dev - 20120503 - $Id: 15d5c781cfcad91193dceae1d2cdd127674ddb3e $
mysql
Uptime: 1857223 Threads: 1 Questions: 4446069 Slow queries: 32 Opens: 465 Flush tables: 1 Open tables: 403 Queries per second avg: 2.393
5.6.25-73.1

Fri, 04 Sep 2015 12:01:10 +0100
FOUND ROWS = 0
FOUND ROWS = 0
FOUND ROWS = 59836
FOUND ROWS = 0
FOUND ROWS = 59836

推荐答案

问题已解决.事实证明，NewRelic Application Monitoring守护程序或扩展正在干扰FOUND_ROWS()的结果

Problem solved. It turns out the NewRelic Application Monitoring Daemon or extension was interfering with the results of FOUND_ROWS()

那太糟糕了:(

禁用扩展名和FOUND_ROWS再次防弹

Disabling the extension and FOUND_ROWS is bulletproof again

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