Redirection increase the length of my URL

[eluser]dunicorn[/eluser]
if it was

Code:

http://localhost/abc/index.php?ref=main

after redirection, the url in the browser will be

Code:

http://localhost/abc/index.php/index.php?ref=home

[eluser]Narkboy[/eluser]
RTFM.

From user guide:

Please note: If you are using query strings you will have to build your own URLs, rather than utilizing the URL helpers (and other helpers that generate URLs, like some of the form helpers) as these are designed to work with segment based URLs.

Redirect is a URL Helper function - ALL of which go some way to building the URL for you.

Either:

Code:

$config['index_page'] = '';

and use mod_rewrite to direct things, or manually redirect using PHP functions, not CI.

The user_guide is your friend. Know it and love it.