Search code examples
phpzend-frameworkdatamappermaster-slave

Master / Slave switch in the Zend Framework application layer


I am writing an application which requires the Master/Slave switch to happen inside the application layer. As it is right now, I instantiate a Zend_Db_Table object on creation of the mapper, and then setDefaultAdapter to the slave.

Now inside of the base mapper classe, I have the following method:

public function useWriteAdapter()
{
    if(Zend_Db_Table_Abstract::getDefaultAdapter() != $this->_writeDb)
    {
        Zend_Db_Table_Abstract::setDefaultAdapter($this->_writeDb);
        $this->_tableGateway = new Zend_Db_Table($this->_tableName);
    }
}

I need a sanity check on this. I don't think the overhead is too much, I just suspect there must be a better way.


Solution

  • An object of type Zend_Db_Table_Row_Abstract remembers what Table object produced it. But you can change the associated Table before you call save().

    $readDb = Zend_Db::factory(...);  // replica
    $writeDb = Zend_Db::factory(...); // master
    Zend_Db_Table::setDefaultAdapter($readDb);
    
    $myReadTable = new MyTable(); // use default adapter
    $myWriteTable = new MyTable($writeDb);
    
    $row = $myTable->find(1234)->current();
    
    $row->column1 = 'value';
    
    $row->setTable($myWriteTable);
    
    $row->save();