The Blogger / Google CDN, And Logout Problems

Recently, we've been seeing queries from some anxious blog owners

Why should I have to sign out a total of three, four, or more times?

With blogs that use a template that shows the navbar, the owner may logout, using the "Sign out" link - but the navbar may continue to suggest that they remain loggedin.

This problem may start with how we connect to Blogger, as part of the mysterious Internet cloud.

Blogger provides multiple connection points ("nodes") to their databases, through the Blogger / Google Content Distribution Network ("CDN"), in many different cities worldwide.

Generally, a blog owner will connect to Blogger, using the closest CDN node. Thanks to Internet Protocol networking with Multipath Routing, the "closest" node won't always be the node with the shortest distance, "as the crow flies", from the owner.

Determining logical distance between 2 computers involves more detail than simple geographical distance. Some blog owners will be equally "close" to multiple nodes - and this is where the problem starts.

All Blogger databases, in all CDN nodes, won't update immediately.

If a blog owner logs out from Blogger, when connected to one node, the Blogger database in other nodes won't always be updated immediately, to reflect the log out status. The CDN nodes update each other periodically - and there is always going to be some delay between updates.

The logical distance between a blog owner and a nearby node can change - and a different node may become "closer", at any time. With multiple nodes equally "close", the slightest change in the network between the blog owner and any "close" nodes can make the blog owner connect to a different node. The blog owner can fluctuate between 2, 3, or more "close" nodes, within seconds.

If the blog owner logs out while connected to one node, then re connects to a second node - before the first node updates with the second - the owner will appear to be still logged in.

Different CDN nodes may show a blog owner as logged in, until updated.

In some cases, the owner can continue to appear as "logged in", when connected to a different node. After logout (log out, signout, sign out) using the "Sign out" link, and the display refreshes, the navbar status will continue to display the account name and "Sign out" link.

Some blog owners will be equally "close" to multiple nodes. They may go through 2, 3, or more sign outs - until all nearby nodes are properly updated, or updated by repeated "Sign out".

Long ago, update delay led to a different mysterious problem.

Long ago, blog owners reported the mysterious advice

You have logged out from another location. Do you want to log in again?

Now, they continue to see the navbar "Sign out" link.

This monolithic error used to make many scream, in anguish.


Previous advice, to workaround the mysterious "You have logged out from another location. Do you want to log in again?", may work for the logout problem.

1. Check cookie and script filters.
2. Clear cache, cookies, and sessions (yes, all 3).
3. Restart the browser.
4. Click on the link below, to login to Blogger.
   

   https://www.blogger.com

A similar example of CDN node update delay involves post editor / template editor.

I see this problem currently, when updating posts. I update my posts, frequently - and see this error message, almost daily.

An error occurred while trying to save or publish your post. Please try again.

Post Editor, showing another monolithic error, after clicking "Update" - just as I updated this post.


There's nothing to do now, but hope for the best. The above procedure may or may not fix this problem.

Template editor will be subject to the same frustration. Any Blogger dashboard change that involves significant delay between opening and saving changes (such as editing) will have a similar problem potential. And here may be one more detail that affects stability of long term draft mode post editor sessions.

If you connect to multiple CDN nodes, while you update a post or edit a template, you end up with "conflicting edits". How should we expect the different database nodes to update each other, consistently, with different edits made to the different nodes?

Some blog owners connect through nodes in different countries.

With "nearby" nodes in different countries, it's possible that country local domains, affected by intrusive cookie or script filters, can complicate this problem. A cookie or script filter can prevent the "Sign out", until the blog owner is connected to a node in a different country.

A cookie or script filter can be a part of many network, performance, or security accessories, on the computer or network. Some filters are updated without knowledge of the blog or computer owner.

Network connections may change in milliseconds.

Multipath routing can cause network connection changes within milliseconds. CDN node updates won't be that frequent. Impatient blog owners may observe the lack of update from "Sign out", and report the problem.

Why would I have to sign out a total of three or more times?

No matter where Google locates their many nodes, some blog owners will be equally "close" to multiple nodes - and their connections can change frequently. The more equally "close" nodes, the more random path changes, and the more this problem will be seen, by different blog owners. Other blog owners won't care, because they may never see this happen.

The new "Responsive" templates may serve as a solution.

The new, "Responsive" class templates lack the navbar, and "Sign out". Blog owners, who publish their blogs to the new templates, won't use the "Sign out" link in the navbar - and they will not observe the delay in CDN node updates.

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Some blog owners report that after logging out from #Blogger, the navbar continues to show that they remain logged in.

Thanks to the Blogger / Google Content Distribution Network, where an owner can connect to any of many different nearby CDN Nodes, this will probably always be with us.