Problem with oracle session

[yyf]

Hi, I connect to an oracle database using OleDbConnection and run quite a number of queries. In the connection string I use everything default, that means the min pool size is 0, max pool size is 100 etc. I don't keep any connection open, as soon as I finish one query I will close the connection and do something else. Also, this is not a multi-thread program. The problem I have now is that I found my program will create more than one sessions in Oracle, the highest number of sessions I found so far is 24, the lowest is 2. I don't know why. Can anyone explain it a little bit and tell me what is the relationship with connection, connection pooling and the actual session in database? Thanks in advance.