More of an ADO Connection Pooling Question

  • ... but I didn't know who else to turn to. 🙂

    We have a web application that recently started throwing "Connection Timeout... connection pool" errors daily. The traffic on the site is comparable to other days. We've been checking the sysprocesses table and have been watching the connections range from 2 - 85. As expected in quiet times the connections are reclaimed. Most of the time the connections are listed as sleeping. We're using the default 100 connections.

    My question is, even if we hit 100 connections, if they're sleeping they should be available in the connection pool, right? I'm thinking that the issue isn't that a connection can't be made, but that something else is happening to cause the timeout.

    Any thoughts?

    We've increased the connection pool to 200 but I feel it's shooting in the dark.

    Thanks

    ST

  • souLTower (11/19/2015)


    ... but I didn't know who else to turn to. 🙂

    We have a web application that recently started throwing "Connection Timeout... connection pool" errors daily. The traffic on the site is comparable to other days. We've been checking the sysprocesses table and have been watching the connections range from 2 - 85. As expected in quiet times the connections are reclaimed. Most of the time the connections are listed as sleeping. We're using the default 100 connections.

    My question is, even if we hit 100 connections, if they're sleeping they should be available in the connection pool, right? I'm thinking that the issue isn't that a connection can't be made, but that something else is happening to cause the timeout.

    Any thoughts?

    We've increased the connection pool to 200 but I feel it's shooting in the dark.

    Thanks

    ST

    You almost certainly have some rogue code somewhere that is not properly disposing of the connection object. The connection must be release back to the pool before it can be reused. What you are describing is the classic symptom of not releasing the connection.

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  • But the system has been operational for 1 1/2 years without throwing this error. The load has not changed dramatically. In the past week a number of MS Server patches and a symantec update have been installed on the servers (Win2008R2, SQL2008R2). The application code has not changed in this time.

    When watching the number of connections I see it increasing and decreasing as I would expect as the pool manages itself. I don't disagree that there could be a connection that's not being closed but would that appear differently when looking at the sysprocesses data or would it also be listed as sleeping?

    Thanks for the response

    ST

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