log4php Failed connecting to mysql cluster database & could not find driver

My log4php gets this error in a new server environment.

PHP Warning: log4php: [LoggerAppenderPDO:default]: Failed connecting to database. Closing appender. Error: could not find driver in ../log4php/LoggerAppender.php on line 283

I have the same settings for log4php (1. config.xml file 2.same log4php version) as my local development, which works perfectly. I tried simply log to a file in the new server, it works, which means the log4php lib has no problem. And I can even log to the database in the new server from my local script using local log4php lib, which means my server can recognize log4php logging.

Reasons:

After some searches and tests(script using PDO, not mysqli to connect to the database, good reference here and wiki) , I confirm the problem is caused by lacking of pdo_mysql related driver. As log4php uses PDO extensions in PHP to  log to mysql database. Then PDO extension is needed. As PDO is defaultly included from PHP5.1, and our mysql-cluster use mysql 5.5, it should be included. But it is not.  I tried to re-install php5-mysql, but it failed, got server related errors; I tried to modify php.ini and add pdo extensions, got more errors. I guess that is because the mysql-cluster settings are different from normal mysql.  But not sure about this. 

To check whether you have PDO driver, you can use:

$php -i

Then you can see the info in the PDO part:

PDO

PDO support => enabled

PDO drivers =>
Normally, if the PDO has driver, the info should be like this:
PDO

PDO support => enabled
PDO drivers => mysql

pdo_mysql

PDO Driver for MySQL => enabled
Client API version => 5.5.35

Directive => Local Value => Master Value

pdo_mysql.default_socket => /var/run/mysqld/mysqld.sock => /var/run/mysqld/mysqld.sock

Work around:

As the new server is a production server, we decide not to touch it and move the scripts to other server with normal mysql settings, which log4php works perfectly.