Sitemap submitted to HTTPS profile also influenced HTTP profile in Google Webmaster Tools

Question

Recently I upgraded a site to use an SSL certificate and noticed strange behaviour with Google Webmaster Tools.

Before starting the changes Google WMT Sitemap for http://www.example.com was showing as 920 pages submitted and 774 indexed.

After getting the site fully working with the SSL certificate, removing the sitemap for http://www.example.com/ and submitting a new sitemap for https://www.example.com/, Google WMT Sitemap for https://www.example.com shows as 920 pages submitted and 799 indexed -- however, Google WMT Sitemap for http://www.example.com has changed to now show as 1840 pages submitted and 1573 indexed, so clearly this has been influenced by the recent submission of the https://www sitemap.

I would be grateful for your thoughts on why this might be.

The traffic (impressions and clicks per day) has remained roughly the same though has gradually moved from the http://www.example.com profile to the https://www.example.com profile as expected.

Answer 1

Google treats the base domain as roll-up of all the subdomains. I have a site with 10 subdomains each with about the same number of pages. In Google Webmaster Tools it reports that the base domain has the sum of the pages on all subdomains indexed, even though the base domain doesn't have that many pages itself.

Based on your findings, it would appear that they treat the http:// site as a roll-up of https:// site as well. Indexed https pages count towards the total of indexed http pages.