If you are outside of the country for over 6 months (182 days I believe is the exact figure) the your world wide income is still taxable but at a reduced rate, 25% i believe.
Once you declare yourself a non-resident, then no tax issues.
I consulted an accountant to handle my case, went smoothly, never questioned about it since.
As for investments, i.e. RRSP's etc, there is a 25% tax treaty in pace with the UAE. You have 2 choices; cash them in when you retire, or cash them in when you are living in the UAE and pay 25%. One note is that if you do decide to keep them while abroad, you cannot contribute to them at all.