Thanks to all those who responded. Some web applications do use connection pooling and some don't. I will need to find out the upper limits on the session pool size and also the rate of session starts. Thanks for the pointers. Thanks, Sunil. On 9/18/07, Nigel Thomas <nigel_cl_thomas@xxxxxxxxx> wrote: > > ----- Original Message ---- > From: Sunil Kanderi sunil.kanderi@xxxxxxxxx > > > .... We have lots of web applications running from that database and once > in a while there is a sudden spike in the number of connections from a > Oracle user related to one of the web applications and the concurrent > connections for that particular web application user jumps from 10 or 15 > concurrent connections to 100s in less than a couple of minutes. The > database and the server hang until these connections are cleared. At times > we cannot even get a connection to the server when this happens. I usually > don't see any alerts in the alert log when this happens. > --------------- > > Sunil > > From this, I can't say why you see the initial slowdown - but I can say it > is common for connection pools to behave suicidally when faced with a slow > down. Traffic piling into the connection pool causes an explosion in the > number of connections - and there's nothing like a flood of new connections > to make the traffic jam worse. See > http://preferisco.blogspot.com/2007/02/avoiding-application-suicide-by-session.html > . > > Regards Nigel >