Apex Listener config recommendations

Question

Our DBA is installing Apex Listener 1.1.2.131.15.23 for the first time, and had a question regarding some setup. Right now it's just a stand alone copy. In the JDBC Settings, what are your recommendations for the following settings?
Initial Pool Size: 3
Maximum Statements: 10
Minimum Connections: 1
Inactivity Timeout: 1800 seconds
Maximum Connections: 10
Abandoned Connection Timeout: 900 seconds
If there is some recommended reading on how to determine the best way to set this up, that would be great.

Answer 1

Hello Rick,
it's hard to give you actual values. These settings concern, more or less, your load expectations. The numbers you need are
- average number of concurrent sessions (work load)
- maximum number of concurrent sessions (peek load)
Some settings might as well depend on your applications.
Recommended reading would be the Table A-1 of the Installation and Developers Guide, where the parameters you picked are described among other configuration parameters.
Just some thoughts on connection handling:
The APEX Listener uses a pool of connections to the database that is shared among all users. Usually it would be a waste of resources to have a dedicated connection for each application session, as there are usually times when there's no user activity, e.g. when a user is reading a report. So you want to make the pool size as small as possible without negative impact on your user experience. To achieve this, you may initialize your pool to be able to serve your average work load and allow it to grow to the expected peek. You may want to set the minimum number of connections below that value, so resource consumption is reduced in times of low charge.
The timeouts concern the reduction of the pool size due to reduced load (inactivity timeout - a connection isn't needed any more) or failures or unexpected long database reaction times (abandoned connection).
Statements caching can reduce database load and response times, but increases resource consumption of the Listener and may result in inacurate results if cached values are outdated.
If you have more practical questions on that topic, don't hesitate to ask.
-Udo