SEO - really long URLs

[MPDev]

Does anyone know if Google looks at the length of a URL when indexing it or giving it its relevence? If I have a URL that is, say, 400 characters long versus 50 characters long; will it make any kind of different to the positioning in search engines?

I ask this because I have a choice in passing data from one page to the next for a project - I can either store the data in a database with an index key as a parameter, or I can tack the data onto the URL for each subsequent page clicked on. If I do it without the database, the URL will grow very quickly and contain actual URLs to pages in the history that took them to where they are. Would having a really long URL or multiple web addresses effect the indexing of the pages when the spiders traverse through the pages?

The difference would be:

http://www.mysite.com/thisparm-data/thatparm-data/key-nnnn

versus

http://www.mysite.com/thisparm-data/thatparm-data/h1-http:~~www.mysite.com~thisparm-data~thatparm-data~n1-search1/n1-searchx/h2-http:~~www.mysite.com~thisparm-data~thatparm-data/h1-http:~~www.mysite.com~thisparm-data~thatparm-data~n1-search1/n2-search2

(this URL would grow for every level the user drills down, so those hX/nX parameters would get really long after 2 or 3 levels) and could easily exceed hundreds of characters - if not more than 1k.