General error: 2006 MySQL server has gone away
- 错误原因
- 制造错误
- 解决办法
- 最新办法
错误原因
Mysql has gone away
- MySQL 服务宕了
- mysql连接超时 show global variables like ‘%timeout’;
- mysql请求链接进程被主动kill show global status like ‘com_kill’;
- Your SQL statement was too large. show global variables like ‘max_allowed_packet’;
制造错误
造一个表
-- ----------------------------
-- Table structure for t_biubiu
-- ----------------------------
DROP TABLE IF EXISTS `t_biubiu`;
CREATE TABLE `t_biubiu` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`value` varchar(255) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;然后造一个程序
public function actionInsert(){
Biubiu::model()->findAll();
$result = Yii::app()->db->createCommand("show global variables like '%timeout'")->queryAll();
self::show_vars($result);
for($index = 1 ;$index< 10;$index++){
$model_ = new Biubiu();
$model_->value = "insert".$index;
if($index == 8){
sleep(31);
}
$model_->save();
}
$model = new Biubiu();
$model->value = "insert4";
$model->save();
}设置你的MYSQL的wait_timeout = 30，interactive_timeout也要设置，否则不生效
执行的时候就会抛异常：
exception 'CDbException' with message 'CDbCommand failed to execute the SQL statement: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away. The SQL statement executed was: INSERT INTO `t_biubiu` (`value`) VALUES (:yp0). Bound with :yp0='insert8'' in E:\phpWorks\framework\db\CDbCommand.php:362sleep有效果了。
大部分情况就是超时导致的，尤其是脚本执行时间太长
解决办法
如果运维不同意 改变wait_timeout的值：
| 方法 | 做法 |
|---|---|
| 1 | wait_timeout改大一些，并不能一劳永逸 |
| 2 | 代码中遇到超时重连 |
| 3 | 检查是不是Mysql连接过多，并发太高，忘记释放连接 |
解决方法推荐
例如，读写分离的 JDbConnection。在调用save delete方法的时候执行ensureActive() 。注意 @，否则异常发生的时候PHP ERROR直接挂掉。
<?php
/**
* JDbConnection(Database Connection Manager) class is a manager of database connections.
*
* for the purpose of database read/write splitting.
* It override the createCommand method,
* detect the sql statement to decide which connection will be used.
* Default it use the master connection.
*
*/
class JDbConnection extends CDbConnection
{
/**
* @var array $slaves.Slave database connection(Read) config array.
* The array value's format is the same as CDbConnection.
* <code>
* 'components'=>array(
* 'db'=>array(
* 'class' => 'JDbConnection',
* 'connectionString'=>'MySQL://<master>',
* 'slaves'=>array(
* array('connectionString'=>'mysql://<slave01>'),
* array('connectionString'=>'mysql://<slave02>'),
* )
* )
* )
* </code>
*/
public $slaves = array();
/**
* Whether enable the slave database connection.
* Defaut is true.Set this property to false for the purpose of only use the master database.
*
* @var bool $enableSlave
*/
public $enableSlave = true;
/**
* @var CDbConnection
*/
private $_slave;
/**
* Creates a CDbCommand object for excuting sql statement.
* It will detect the sql statement's behavior.
* While the sql is a simple read operation.
* It will use a slave database connection to contruct a CDbCommand object.
* Default it use current connection(master database).
*
* @override
* @param string $sql
* @return CDbCommand
*/
public function createCommand($query = null)
{
if ($this->enableSlave && !$this->getCurrentTransaction() && self::isReadOperation($query)) {
return $this->getSlave()->createCommand($query);
} else {
return parent::createCommand($query);
}
}
/**
* Construct a slave connection CDbConnection for read operation.
*
* @return CDbConnection
*/
public function getSlave()
{
if (!isset($this->_slave)) {
foreach ($this->slaves as $slaveConfig) {
if (!isset($slaveConfig['class']))
$slaveConfig['class'] = 'CDbConnection';
try {
if ($slave = Yii::createComponent($slaveConfig)) {
Yii::app()->setComponent('dbslave', $slave);
$this->_slave = $slave;
break;
}
} catch (Exception $e) {
Yii::log('Create slave database connection failed!', 'warn');
continue;
}
}
if (!$this->_slave) {
$this->_slave = clone $this;
$this->_slave->enableSlave = false;
}
}
return $this->_slave;
}
/**
* Detect whether the sql statement is just a simple read operation.
* Read Operation means this sql will not change any thing ang aspect of the database.
* Such as SELECT,DECRIBE,SHOW etc.
* On the other hand:UPDATE,INSERT,DELETE is write operation.
*
* @return bool
*/
public function isReadOperation($sql)
{
return !!preg_match('/^\s*(SELECT|SHOW|DESCRIBE|PRAGMA)/i', $sql);
}
/**
* 确保数据库连接有效
*
* @params bool $isSlaveping主库还是从库
* @return void
*/
public function ensureActive($isSlave = true)
{
if ($this->getActive()) {
try {
@$this->getPdoInstance()->query('SELECT 1');
} catch (PDOException $e) {
$this->setActive(false);
$this->setActive(true);
}
}
}
}
调用示例：
Yii::app()->db->ensureActive();另外一种方法
执行SQL之前执行：
Yii::$app->db->createCommand('SET SESSION wait_timeout = 28800;')->execute();最新办法
避免每次多请求了一次数据库。只有在遇到问题时进入异常处理，重试的时候Yii会自动进行重连[不确定]。
public static function retry($params, $call){
for($retry = 0; $retry < 3;$retry++){
try{
if($params instanceof CModel){
return $params->$call();
}
}catch(CDbException $e){
if (!(strpos($e, "error: 2006") && !strpos($e, "error: 2013"))) {
throw new Exception($e->getMessage(), 520);
}
}
}
return false;
}2017年4月9日 更新
最近发现，公司所用的yii framework1.1的框架，和官方下载的不太一样。
下载最新框架，测试代码如下，我将mysql设置为wait_timeout=30, interactive_timeout=30
class DbTestCommand extends CConsoleCommand {
public function actionInsert(){
$sql = "insert into adv_pro ( `name` , `int_value`) values ('insert', 100)";
Yii::app()->localdb->createCommand($sql)->execute();
sleep(31);
$sql = "insert into adv_pro ( `name` , `int_value`) values ('insert', 200)";
Yii::app()->localdb->createCommand($sql)->execute();
}
}结果就出现了：
PHP Error[2]: PDOStatement::execute(): MySQL server has gone away
in file D:\work_project\framework\db\CDbCommand.php at line 336
#0 D:\work_project\framework\db\CDbCommand.php(336): PDOStatement->execute()
#1 D:\work_project\task\protected\commands\DbTestCommand.php(19): CDbCommand->execute()
#2 unknown(0): DbTestCommand->actionInsert()再加上@符号抑制错误
@Yii::app()->localdb->createCommand($sql)->execute();结果异常就抛出来了：
exception 'CDbException' with message 'CDbCommand failed to execute the SQL statement: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away. The SQL statement executed was: insert into adv_pro ( `name` , `int_value`) values ('insert', 200)' in D:\work_project\framework\db\CDbCommand.php:363
Stack trace:
#0 D:\work_project\task\protected\commands\DbTestCommand.php(19): CDbCommand->execute()那么可以把框架的db/CDbCommand.php内的execute方法改一下，改成：
if($params===array())
@$this->_statement->execute();
else
@$this->_statement->execute($params);这样就能捕获到这个异常了。
那么据此，可以为CDbCommand.php增加一个方法：
public function sqlDbExecute($params=array()){
$e = new Exception("sqlDbExecute failed three times", 10001);
for ($count=0;$count<3;$count++){
try {
$result = $this->execute($params);
return $result;
} catch (Exception $e) {
Yii::log('Error in sqlDbExecute SQL: '.$this->getText(),CLogger::LEVEL_ERROR,'system.db.CDbCommand');
$this->_connection->setActive(true);
//If not found 2006 then throw up
if (!strpos($e, "error: 2006")) {
throw new Exception($e,10001);
}
}
}
throw new Exception($e,10001);
}