Is it good idea that the old URL are being submitted in sitemap to crawled faster and Google will index those old URL and only new URL will be shown in the results?
JOHN MEULLER (Webmaster Analyst from Google):
Usually we pick up on those kind of redirects fairly quickly. If we’re not picking up on them individually, then you can let us know about that through a site map, for example, depending on how big your site is, how big those changes are there. But in general, you wouldn’t need to do that. So that’s something that will happen on our side anyway. Sometimes what will happen is you will redirect from one URL to another URL. But if you specifically search for the older URL, you’ll still find that in search. So that’s specifically visible when you move from one site to another. If you do a site query for the old domain, then maybe you’ll still find hundreds or thousands of URLs there. But if you search for that content by looking for the keywords that you’re normally ranked for, you’ll see that your new domain actually ranks for that content, so in a case like that, we know about the old URLs. We know about the new URLs. We know that if you’re specifically searching for those old URLs, then maybe that’s something we would show you because we know about that. So it’s not the case that it’s a technical problem or that you’ll be penalized for duplicate content or anything like that. It’s just we understand the old URLs are still around, and if someone explicitly searches for them, maybe we should just show them.