I got this error in ULS log file while using one SharePoint application which was developed by third party. I have checked the code and it was disposing the SP objects correctly.
The site was running really slow, and it takes about 40 seconds to load the home page.
Our application has 5 sites under a site collection and about 500 sub sites underneath those 5 sites.
Reason of error:
The “show subsites” option in navigation setting was checked, so when the page loads it also load 5 sites in navigation menu and all 500 sub sites links as a dropdown link menu. The navigation menu is shipped with SharePoint product, the way it is designed that it use SP Request object to build each navigation link and doesn’t dispose those object automatically (Reason: if the page do refresh, it does not need to re-create all object again)
Go to site collection home page
Click site action> site settings
Click “Navigation” link under “Look and Feel” section
Uncheck “Show sub sites” under “global navigation” and “current navigation” as shown below
If you need that navigation link for all sub sites should be available for user, think about other ways to getting this functionality (e.g. custom navigation), or reconsider your application structure.
After doing the above changes, I did not see any log saying “Potentially excessive number of SPRequest objects“. Also site performance increased dramatically as the home page loads in 4 seconds. J
Hope this will help.