Google Analytics CDN Cookie Issue on a Non-www domain -

i trying apply cloudfront cdn on 1 of wordpress websites, using w3 total cache.

someone know told me change google analytics ['_setdomainname', 'www.example.com'] in order explicitly track main site , not cdn sub domains

but site non-www site , has been indexed in google according that.

will change prevent tracking? necessary?

first: change not prevent tracking.

second: why want prevent tracking user accessing site through cdn?

this contrary should do. final user shouldn't matter if seeing cached version or not. in terms on analytics it's better have view of big picture.