I am facing one issue with master and slave replication setup on Magento 1.12. I am using MYSQL for master and slave replication and replication is working fine on MYSQL level. After this I am using local.xml for telling Magento about the default read database for SLAVE.
This works fine when I try to save anything from admin. I had verified that in most of the cases the SELECT queries are getting fired properly from SLAVE and INSERT or UPDATE queries are getting fired on MASTER by logging the queries. But in few scenarios this is failing.
E.g. If I run the the very first page of Magento admin (i.e. Login Page) then observed that the indexer query is getting fired from MASTER. Please check the following sample query log along with the backtrace.
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DB TYPE: Master
QUERY
SQL: SELECT `index_process`.`indexer_code` FROM `index_process`
TRACE: #1 Varien_Db_Adapter_Pdo_Mysql#0000000073e6271600000000edf479e5#->_debugStat(2, 'SELECT `index_pr...', array(), &Varien_Db_Statement_Pdo_Mysql#0000000073e6277100000000edf479e5#) called at [lib\Varien\Db\Adapter\Pdo\Mysql.php:424]
#2 Varien_Db_Adapter_Pdo_Mysql#0000000073e6271600000000edf479e5#->query(&Varien_Db_Select#0000000073e6272600000000edf479e5#, array()) called at [lib\Zend\Db\Adapter\Abstract.php:791]
#3 Varien_Db_Adapter_Pdo_Mysql[Zend_Db_Adapter_Abstract]#0000000073e6271600000000edf479e5#->fetchCol(&Varien_Db_Select#0000000073e6272600000000edf479e5#) called at [app\code\core\Mage\Index\Model\Resource\Setup.php:66]
#4 Mage_Index_Model_Resource_Setup#0000000073e6275d00000000edf479e5#->_syncIndexes() called at [app\code\core\Mage\Index\Model\Resource\Setup.php:45]
#5 Mage_Index_Model_Resource_Setup#0000000073e6275d00000000edf479e5#->applyUpdates() called at [app\code\core\Mage\Core\Model\Resource\Setup.php:235]
#6 Mage_Core_Model_Resource_Setup::applyAllUpdates() called at [app\code\core\Mage\Core\Model\App.php:417]
#7 Mage_Core_Model_App#0000000073e6271d00000000edf479e5#->_initModules() called at [app\code\core\Mage\Core\Model\App.php:343]
#8 Mage_Core_Model_App#0000000073e6271d00000000edf479e5#->run(array('scope_code' => '', 'scope_type' => 'store', 'options' => array())) called at [app\Mage.php:683]
#9 Mage::run('', 'store') called at [index.php:87]
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I am seeking guidance from anyone who faced similar kind of issues and able to find some work around about this issue. Otherwise I will have to forward this issue to Magento Support in order to get answer.
