Cannot finish Analytics page tracking

Question

I have the following exception appearing in my log files at a rate of 2-3 per second.

ERROR Cannot finish Analytics page tracking
Exception: Sitecore.Analytics.Exceptions.ContactLockException
Message: Failed to extend contact lease for contact c276821d-a524-419c-8bb5-7a952d1bb319
Source: Sitecore.Analytics
   at Sitecore.Analytics.Tracking.ContactManager.SaveAndReleaseContact(Contact contact)
   at Sitecore.Analytics.Pipelines.EndAnalytics.ReleaseContact.Process(PipelineArgs args)
   at (Object , Object[] )
   at Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args)
   at Sitecore.Analytics.Pipelines.EndAnalytics.EndAnalyticsPipeline.Run()
   at Sitecore.Analytics.Pipelines.HttpRequest.EndAnalytics.Process(HttpRequestArgs args)

The contact Guid is the same every time.

I've found a blog post that describes a similar error, but we're not calling Tracker (or any Sitecore.Analytics code) explicitly in our solution.

Answer 1

Configuring a dedicated Content Management server

Normally, pure CM servers should not read and write interactions and contacts in the collection database. See this official documentation page for more information:

Configure a content management server

The easiest fix for you would be to disable the Sitecore.Analytics.Tracking.Database.config. In any case, make sure to follow the configuration documentation to the letter.

Combined server roles

Your CM can also be combined with another server role. In that case, keep in mind that if the CM doesn't share session databases with your CDs, then it must be considered a part of a separate cluster. This means that it should have the setting Analytics.ClusterName set to a different value.

Further reading:

• Configure a content delivery server
• Clustered server environments

Answer 2

Sitecore has a proper fix for this issue

https://kb.sitecore.net/articles/640114

From the article:

A "failed to extend contact lease" error may occur if large amount of pages were requested within a single interaction.

The following exception can be found in the Sitecore XP log:

316 2017:12:10 16:05:50 ERROR Cannot finish Analytics page tracking
Exception: Sitecore.Analytics.Exceptions.ContactLockException
Message: Failed to extend contact lease for contact ce9c9d9e-2d42-4b82-a871-1a2dd96f050e
Source: Sitecore.Analytics
   at Sitecore.Analytics.Tracking.ContactManager.SaveAndReleaseContact(Contact contact)
   at Sitecore.Analytics.Pipelines.EndAnalytics.ReleaseContact.Process(PipelineArgs args)
   at (Object , Object[] )
   at Sitecore.Pipelines.CorePipeline.Run(PipelineArgs args)
   at Sitecore.Pipelines.DefaultCorePipelineManager.Run(String pipelineName, PipelineArgs args, Boolean failIfNotExists)
   at Sitecore.Analytics.Pipelines.EndAnalytics.EndAnalyticsPipeline.Run()
   at Sitecore.Analytics.Pipelines.HttpRequest.EndAnalytics.Process(HttpRequestArgs args)
Exception is thrown for each next page