How to log MySQL errors to the error file?

[eluser]MatteMatte[/eluser]
Hi Guys,

I have a website powered by CI. In CI, three connections are being made to three different databases at the same time. I wonder how can I log MySQL errors occurring to the log file from all those 3 database connections?

Following config parameters are already set and enabled:

Code:

$config['log_threshold'] = 1;
$config['log_path'] = '/path/to/log/dir';

Any suggestions?