I was working on an ASP page today that included an AJAX call off to trigger various SQL updates, amongst which was a call to a stored procedure. The page started to error with:

Microsoft OLE DB Provider for SQL Server error ‘80040e31’
Timeout expired

The error line was the call to the stored procedure. After a bit of fiddling around I traced the issue to the ADO ConnectionTimeOut value. By default this is 30 seconds.

There are, I guess, 3 timeout values of interest on an ASP page:

1. Session timeout

How long the user’s browser session will last. On IIS this is defaulted to 20 minutes

2. Script timeout

How long a page can take to complete. On IIS this is defaulted to 90 seconds.

3. Connection timeout

How long a single call to the database can take to complete. This defaults to 30 seconds.

The stored procedure was taking > 30 seconds, hence throwing an error. I solved the problem by increasing the ConnectionTimeOut value for the particular call to the stored procedure, eg:

Dim cmdC
Set cmdC = Server.CreateObject("ADODB.Command")
with cmdC
.ActiveConnection = conn
.CommandText = "[procedure name]"
.CommandType =adCmdStoredProc
.CommandTimeout = 3000
.Execute
end with

The value is in seconds, so 3000 seconds = 5 minutes. You can read more about ConnectionTimeOut here.

Of course, there’s a whole other discussion why we have a stored procedure taking so long to run as part of an AJAX call. We’ll probably shift it off to a scheduled job or something eventually but we needed a quick fix for the interim.