Yii框架数据库多数据库、主从、读写分离 实现
功能描述：
1.实现主从数据库读写分离 主库：写 从库(可多个)：读
2.主数据库无法连接时 可设置从数据库是否 可写
3.所有从数据库无法连接时 可设置主数据库是否 可读
4.如果从数据库连接失败 可设置N秒内不再连接
利用yii扩展实现：
| 代码如下 | 复制代码 |
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<?php /** * 主数据库 写 从数据库（可多个）读 * 实现主从数据库 读写分离 主服务器无法连接 从服务器可切换写功能 * 从务器无法连接 主服务器可切换读功 * by lmt * */ class DbConnectionMan extends CDbConnection { public $timeout = 10; //连接超时时间 public $markDeadSeconds = 600; //如果从数据库连接失败 600秒内不再连接 //用 cache 作为缓存全局标记 public $cacheID = 'cache'; /** * @var array $slaves.Slave database connection(Read) config array. * 配置符合 CDbConnection. * @example * 'components'=>array( * 'db'=>array( * 'connectionString'=>'mysql://<master>', * 'slaves'=>array( * array('connectionString'=>'mysql://<slave01>'), * array('connectionString'=>'mysql://<slave02>'), * ) * ) * ) * */ public $slaves = array(); /** * * 从数据库状态 false 则只用主数据库 * @var bool $enableSlave * */ public $enableSlave = true; /** * @var slavesWrite 紧急情况主数据库无法连接 切换从服务器（读写）. */ public $slavesWrite = false; /** * @var masterRead 紧急情况从主数据库无法连接 切换从住服务器（读写）. */ public $masterRead = false; /** * @var _slave */ private $_slave; /** * @var _disableWrite 从服务器（只读）. */ private $_disableWrite = true; /** * * 重写 createCommand 方法,1.开启从库 2.存在从库 3.当前不处于一个事务中 4.从库读数据 * @param string $sql * @return CDbCommand * */ public function createCommand($sql = null) { if ($this->enableSlave && !empty($this->slaves) && is_string($sql) && !$this->getCurrentTransaction() && self::isReadOperation($sql) && ($slave = $this->getSlave()) ) { return $slave->createCommand($sql); } else { if (!$this->masterRead) { if ($this->_disableWrite && !self::isReadOperation($sql)) { throw new CDbException("Master db server is not available now!Disallow write operation on slave server!"); } } return parent::createCommand($sql); } } /** * 获得从服务器连接资源 * @return CDbConnection * */ public function getSlave() { if (!isset($this->_slave)) { shuffle($this->slaves); foreach ($this->slaves as $slaveConfig) { if ($this->_isDeadServer($slaveConfig['connectionString'])) { continue; } if (!isset($slaveConfig['class'])) $slaveConfig['class'] = 'CDbConnection'; $slaveConfig['autoConnect'] = false; try { if ($slave = Yii::createComponent($slaveConfig)) { Yii::app()->setComponent('dbslave', $slave); $slave->setAttribute(PDO::ATTR_TIMEOUT, $this->timeout); $slave->setAttribute(PDO::MYSQL_ATTR_USE_BUFFERED_QUERY, true); $slave->setActive(true); $this->_slave = $slave; break; } } catch (Exception $e) { $this->_markDeadServer($slaveConfig['connectionString']); Yii::log("Slave database connection failed!ntConnection string:{$slaveConfig['connectionString']}", 'warning'); continue; } } if (!isset($this->_slave)) { $this->_slave = null; $this->enableSlave = false; } } return $this->_slave; } public function setActive($value) { if ($value != $this->getActive()) { if ($value) { try { if ($this->_isDeadServer($this->connectionString)) { throw new CDbException('Master db server is already dead!'); } //PDO::ATTR_TIMEOUT must set before pdo instance create $this->setAttribute(PDO::ATTR_TIMEOUT, $this->timeout); $this->open(); } catch (Exception $e) { $this->_markDeadServer($this->connectionString); $slave = $this->getSlave(); Yii::log($e->getMessage(), CLogger::LEVEL_ERROR, 'exception.CDbException'); if ($slave) { $this->connectionString = $slave->connectionString; $this->username = $slave->username; $this->password = $slave->password; if ($this->slavesWrite) { $this->_disableWrite = false; } $this->open(); } else { //Slave also unavailable if ($this->masterRead) { $this->connectionString = $this->connectionString; $this->username = $this->username; $this->password = $this->password; $this->open(); } else { throw new CDbException(Yii::t('yii', 'CDbConnection failed to open the DB connection.'), (int) $e->getCode(), $e->errorInfo); } } } } else { $this->close(); } } } /** * 检测读操作 sql 语句 * * 关键字： SELECT,DECRIBE,SHOW ... * 写操作:UPDATE,INSERT,DELETE ... * */ public static function isReadOperation($sql) { $sql = substr(ltrim($sql), 0, 10); $sql = str_ireplace(array('SELECT', 'SHOW', 'DESCRIBE', 'PRAGMA'), '^O^', $sql); //^O^,magic smile return strpos($sql, '^O^') === 0; } /** * 检测从服务器是否被标记 失败. */ private function _isDeadServer($c) { $cache = Yii::app()->{$this->cacheID}; if ($cache && $cache->get('DeadServer::' . $c) == 1) { return true; } return false; } /** * 标记失败的slaves. */ private function _markDeadServer($c) { $cache = Yii::app()->{$this->cacheID}; if ($cache) { $cache->set('DeadServer::' . $c, 1, $this->markDeadSeconds); } } } |
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main.php配置：components 数组中
| 代码如下 | 复制代码 |
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'db'=>array( 'class'=>'application.extensions.DbConnectionMan',//扩展路径 'connectionString' => 'mysql:host=192.168.1.128;dbname=db_xcpt',//主数据库 写 'emulatePrepare' => true, 'username' => 'root', 'password' => 'root', 'charset' => 'utf8', 'tablePrefix' => 'xcpt_', //表前缀 'enableSlave'=>true,//从数据库启用 'urgencyWrite'=>true,//紧急情况 主数据库无法连接 启用从数据库 写功能 'masterRead'=>true,//紧急情况 从数据库无法连接 启用主数据库 读功能 'slaves'=>array(//从数据库 array( //slave1 'connectionString'=>'mysql:host=localhost;dbname=db_xcpt', 'emulatePrepare' => true, 'username'=>'root', 'password'=>'root', 'charset' => 'utf8', 'tablePrefix' => 'xcpt_', //表前缀 ), array( //slave2 'connectionString'=>'mysql:host=localhost;dbname=db_xcpt', 'emulatePrepare' => true, 'username'=>'root', 'password'=>'root', 'charset' => 'utf8', 'tablePrefix' => 'xcpt_', //表前缀 ), ), ), |
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时间： 2024-10-26 17:01:24