Questions about Google XML Sitemap

[Marfola]

I submit my updated sitemap via an HTTP request as outlined in the page [google.com...]

The sitemap includes all of my pages - new, recently modified and otherwise. I use both the priority and last modified tags. Is it necessary to ping google daily with all the urls? Would it be wiser to include only the urls for new and modified pages? Or possibly, only ping google when there are changes, ie new or modified pages?

Moreover, according to this article "The Submitted column will continue to show the last time you manually clicked the link, but the Last Downloaded column will be updated to show the last time our system has fetched your Sitemap."

Webmaster tools is, however, always shows the same date for both. Of note, I haven't manually resubmitted the sitemap for several months.

[tedster]

The date in WMT may be buggy - sounds like it is in your case anyway. You only need to ping Google (via http) when the sitemap changes, but manually submitting it again might help to move things along for you. Can't hurt, right?

[Marfola]

Thanks Tedster. I have another problem:

The overview page of Sitemaps section in Webmaster tools is showing:

Sitemap statistics:
URLs submitted: 2272
Indexed URLs: 1

Yet a quick shows that nearly all of the pages are indexed. Could the ping be the cause of the discrepancy also?

[Marfola]

Based on the suggestions to this question in the google webmaster forum, I've removed the daily ping. The 'Submitted Date' is now showing the last ping date. The 'Download Date' updates daily. Looks like the ping is really unnecessary.