ZF oracle连接池

各位高手能不能指点下在ZF框架下如何实现ORACLE数据库的连接池，我的程序并发700数据库访问不到了直接报错。错误如下：

Fatal error: Uncaught exception 'Zend_Db_Adapter_Oracle_Exception' with message '12519 ORA-12519: TNS:no appropriate service handler found *' in /data/www/caijing/libs/Zend/Db/Adapter/Oracle.php:122 Stack trace: #0 /data/www/caijing/libs/Zend/Db/Adapter/Abstract.php(713): Zend_Db_Adapter_Oracle->_connect() #1 /data/www/caijing/libs/Zend/Db/Adapter/Abstract.php(777): Zend_Db_Adapter_Abstract->quote('TB_ORDER', NULL) #2 /data/www/caijing/libs/Zend/Db/Adapter/Oracle.php(299): Zend_Db_Adapter_Abstract->quoteInto('UPPER(TC.TABLE_...', 'TB_ORDER') #3 /data/www/caijing/libs/Zend/Db/Table/Abstract.php(595): Zend_Db_Adapter_Oracle->describeTable('TB_ORDER', NULL) #4