We have a Delphi 7 application that runs as an ISAPI extension in IIS6. The code use ADO to connect to a MS SQL 2000 database and performs many reads on the database (no writes). If I watch the audit login and logout events in SQL profiler I can see that numerous requests to the app result in only 1 audit login event. However, if I run that same code from outside IIS (i.e. a test app calling the same method in the dll) I see many login and logout events. My guess is that IIS is performing some automatic connection pooling without my doing anything. I’d like to see the same behavior when I run the dll from outside of IIS for performance reasons – the app is almost 100% slower in this situation. How can I get ADO connection pooling when the dll runs outside of IIS?
EDIT – I’m actually using the SQL ole provider. The connection string looks like this:
Provider=SQLOLEDB.1;Initial Catalog=%s;Data Source=%s;Password=%s;User ID=%s;Pooling=True;Min Pool Size=5;Max Pool Size=50;Connection Lifetime=120
I tried adding the Pooling=True attribute but this doesn’t change things. Also, I learned that audit login and logout events don’t necessarily change for connection pooling so I started using the Logins/sec, Logouts/sec and User Connections performance counters (SQLServer:GeneralStatistics) to determine if connection pooling occurs. From inside IIS I see many logins/sec and no logouts/sec. Outside of IIS I see many logins and logouts per second and user connections fluctuates (it holds steady in IIS).
It’s hard to say based on the info given, but connection pooling is definitely based off of the connection string – if the connection string is exactly the same then the connection can be pooled… it sounds like your outside application may be altering the connection string?
IIS isn’t pooling ADO connections. It is likely caching the ISAPI dll though. Are you starting/stopping your outside application continuously? Or is it a single run causing multiple login events?