Does anyone ever has an experince, filling in embassy and got their Green card within 6 weeks?

Are you talking about the visa or the actual green card? It is highly dependent on your embassy how fast the process goes for the visa. To get a better answer to your question, you should ask did anyone file at your embassy at which you are eligible to file and how long did it take. For the green card, that normally comes 4 weeks or so after arrival in the US.

I am talking about immigrant visa CR1, UAE embassy

I have no knowledge of the UAE, but we are moving pretty fast here for DCF in India, and from I-130 petition being filed to our CR1 Interview it is 8 weeks... Maybe things move faster there, but WOW, that would be super-duper fast.

Try posting in the appropriate regional category, someone might be able to give you a clearer answer for your Embassy/Consulate.

Good Luck!

From filing to green card in 6 weeks? I hardly think so. Even with DCF, suposedly faster, I've never heard of anyone getting their visa in 6 weeks. And remember, the green card is not issued until you move to the US.