Database

1. Turn on debugging as adb instanced in include/database/PearDatabase (at end of file)

if(empty($adb)) {

   $adb = new PearDatabase(); 
   $adb->connect();
   // ADD THIS LINE
   $adb->setDebug(true);

}

PHP

1. Turn on log4php.debug library usage, in file config.performance.php

'LOG4PHP_DEBUG' => true,

2. Set the log level, in file log4php.properties

log4php.rootLogger = DEBUG, A1

NOTE:

Make sure logs/ folder has write access to apache server process owner.

1. In file, Smarty_setup.php add the following to class consturctor function

function vtigerCRM_Smarty() {

   $this->Smarty();
   $this->template_dir = 'Smarty/templates';
   // ...
   // ADD THIS LINE
   $this->debugging = true;

}