My server runs CentOS 6.4 with MySQL 5.1.69 installed using yum with CentOS's repos, and PHP 5.4.16 installed using yum with ius's repos. Edit3 Upgraded to MySQL Server version: 5.5.31 Distributed by The IUS Community Project, and error still exists. Then changed library to mysqlnd, and seems to eliminate the error. Still, with this back and forth, need to know why this error only sometimes manifests.
When using PDO and creating the PDO object using PDO::ATTR_EMULATE_PREPARES=>false, I sometimes get the following error:
Table Name - zipcodes
Error in query:
SELECT id FROM cities WHERE name=? AND states_id=?
SQLSTATE[HY000]: General error: 2014 Cannot execute queries while other unbuffered queries are active. Consider using PDOStatement::fetchAll(). Alternatively, if your code is only ever going to run against mysql, you may enable query buffering by setting the PDO::MYSQL_ATTR_USE_BUFFERED_QUERY attribute.
File Name: /var/www/initial_install/build_database.php
Line: 547
Time of Error: Tuesday July 2, 2013, 5:52:48 PDT
Line 547 is the last line of:
$stmt_check_county->execute(array($data[5],$data[4]));
if(!$county_id=$stmt_check_county->fetchColumn())
{
$stmt_counties->execute(array($data[5]));
$county_id=db::db()->lastInsertId();
}
//$stmt_check_county->closeCursor(); //This will fix the error
$stmt_check_city->execute(array($data[3],$data[4]));
I had a similar problem several years ago, but upgraded from PHP 5.1 to PHP 5.3 (and MySQL probably was updated as well), and the problem magically went away, and now I have it with PHP 5.5.
Why does it only manifest itself when PDO::ATTR_EMULATE_PREPARES=>false, and with only alternating version of PHPs?
I've also found that closeCursor() will also fix the error. Should this always be done after every SELECT query where fetchAll() is not used? Note that the error still occurs even if the query is something like SELECT COUNT(col2) which only returns one value.
Edit By the way, this is how I create my connection. I've only recently added MYSQL_ATTR_USE_BUFFERED_QUERY=>true, however, it doesn't cure the error. Also, the following script could be used as is to create the error.
function sql_error($e,$sql=NULL){return('<h1>Error in query:</h1><p>'.$sql.'</p><p>'.$e->getMessage().'</p><p>File Name: '.$e->getFile().' Line: '.$e->getLine().'</p>');}
class db {
private static $instance = NULL;
private function __construct() {} //Make private
private function __clone(){} //Make private
public static function db() //Get instance of DB
{
if (!self::$instance)
{
//try{self::$instance = new PDO("mysql:host=localhost;dbname=myDB;charset=utf8",'myUsername','myPassword',array(PDO::ATTR_EMULATE_PREPARES=>false,PDO::ATTR_ERRMODE=>PDO::ERRMODE_EXCEPTION,PDO::ATTR_DEFAULT_FETCH_MODE=>PDO::FETCH_ASSOC));}
try{self::$instance = new PDO("mysql:host=localhost;dbname=myDB;charset=utf8",'myUsername','myPassword',array(PDO::ATTR_EMULATE_PREPARES=>false,PDO::MYSQL_ATTR_USE_BUFFERED_QUERY=>true,PDO::ATTR_ERRMODE=>PDO::ERRMODE_EXCEPTION,PDO::ATTR_DEFAULT_FETCH_MODE=>PDO::FETCH_ASSOC));}
//try{self::$instance = new PDO("mysql:host=localhost;dbname=myDB;charset=utf8",'myUsername','myPassword',array(PDO::ATTR_ERRMODE=>PDO::ERRMODE_EXCEPTION,PDO::ATTR_DEFAULT_FETCH_MODE=>PDO::FETCH_ASSOC));}
catch(PDOException $e){echo(sql_error($e));}
}
return self::$instance;
}
}
$row=array(
'zipcodes_id'=>'55555',
'cities_id'=>123
);
$data=array($row,$row,$row,$row);
$sql = 'CREATE TEMPORARY TABLE temp1(temp_id INT UNSIGNED NOT NULL AUTO_INCREMENT, PRIMARY KEY (temp_id) )';
db::db()->exec($sql);
$sql='SELECT COUNT(*) AS valid FROM cities_has_zipcodes WHERE cities_id=? AND zipcodes_id=?';
$stmt1 = db::db()->prepare($sql);
$sql ='SELECT temp_id FROM temp1';
$stmt2 = db::db()->prepare($sql);
foreach($data AS $row)
{
try
{
$stmt1->execute(array($row['zipcodes_id'],$row['cities_id']));
$rs1 = $stmt1->fetch(PDO::FETCH_ASSOC);
//$stmt1->closeCursor();
syslog(LOG_INFO,'$rs1: '.print_r($rs1,1).' '.rand());
$stmt2->execute();
$rs2 = $stmt2->fetch(PDO::FETCH_ASSOC);
syslog(LOG_INFO,'$rs2: '.print_r($rs2,1).' '.rand());
}
catch(PDOException $e){echo(sql_error($e));}
}
echo('done');