The timeout period elapsed prior to obtaining a connection from the pool

Posted on 2011-10-09
Medium Priority
Last Modified: 2012-05-12
We have a web site running on .net + sql server. Recently we are getting the below error:

"Timeout expired.  The timeout period elapsed prior to obtaining a connection from the pool.
This may have occurred because all pooled connections were in use and max pool size was reached. Inner Exception:>>"

It occured not very often. 4,5 times in the last year. The website will return to normal after restarting IIS.

This error clearly states that applicaiton pool have reached the max pool size and it does not have any more connection left for the application to be made to SQL Server.

We doubt that in the code, database connections are being opened but never closed. However, after examining some suspecious moduels, we could not find any of this type of connection. All connections are closed properly.

Is there any way to trouble shoot this problem or to locate the exact problematic point?
Question by:SGSCTC
  • 2
LVL 10

Expert Comment

ID: 36942398
I use IISPeek to determine what is using resources on the webserver in real time.


Author Comment

ID: 37035453
how about IISPeek's impact on the performance? We need to make sure production enviornment won't be affected by our monitoring.  

any other suggestions? I need to find a way to locate where it goes wrong.  
LVL 10

Expert Comment

ID: 37039025
IISPeek's impact is negligible.  It will enable you to find out if there's a page spinning and hanging up your application pool.  It consumes less than 3%CPU and under 100MB RAM when I run it.

I don't know of another solution that would give you the information you need.
LVL 17

Accepted Solution

Rovastar earned 1500 total points
ID: 37186440
I know this is old but you have misunderstood the error message.

This has nothing to do with IIS application pools as you thought  and IISpeek will not help here.

It is to do with connection pools to the database. Connection pools are database terminology and they will differ which DB you are using.


Look at the db end to see the connections being exhausted.

For the question "request attention" and add more zones for the database technology you are using. for more detailed help.

Featured Post


Modern healthcare requires a modern cloud. View this brief video to understand how the Concerto Cloud for Healthcare can help your organization.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Color can increase conversions, create feelings of warmth or even incite people to get behind a cause. If you want your website to really impact site visitors, then it is vital to consider the impact color has on them.
Q&A with Course Creator, Mark Lassoff, on the importance of HTML5 in the career of a modern-day developer.
The viewer will learn how to look for a specific file type in a local or remote server directory using PHP.
The viewer will get a basic understanding of what section 508 compliance can entail, learn about skip navigation links, alt text, transcripts, and font size controls.
Suggested Courses
Course of the Month15 days, 10 hours left to enroll

850 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question