Description

There are several known issues that might cause degradation of media request performance when xDB is enabled. Their symptoms are:

• Slower response times for images compared to the previous versions.
• The same images might load slower from time to time randomly.

The issue is caused while the session state is added for media requests. The following exceptions might appear in the log records:

ERROR Application error.
Exception: System.Web.HttpException
Message: The request queue limit of the session is exceeded.
Source: System.Web
   at System.Web.SessionState.SessionStateModule.QueueRef()
   at System.Web.SessionState.SessionStateModule.PollLockedSession()
   at System.Web.SessionState.SessionStateModule.GetSessionStateItem()
   at System.Web.SessionState.SessionStateModule.BeginAcquireState(Object source, EventArgs e, AsyncCallback cb, Object extraData)
   at System.Web.HttpApplication.AsyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step)
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

Solution

To resolve the issue, consider one of the following options:

• Upgrade Sitecore XP instance to Sitecore XP 9.3 or later.
• Download and install the hotfix compatible with the affected product version:
  
  • For Sitecore XP 9.2: SC Hotfix 413550-1.zip
  • For Sitecore XP 9.1.1: SC Hotfix 436925-1.zip
  • For Sitecore XP 9.1.0: SC Hotfix 475575-1.zip

  Be aware that the hotfixes were built for specific Sitecore XP versions, and must not be installed on other Sitecore XP versions or in combination with other hotfixes. In case any other hotfixes have already been installed on a certain Sitecore XP instance, send a request for a compatibility check to Sitecore Support.

  Note that the ZIP file contents must be extracted to locate installation instructions and related files inside. The hotfixes must be installed on a CM instance and then synced with other instances using standard development practices.