在 JBoss 中指定数据源的最小和最大池大小

Question

I will deploy a web application that will run on JBoss 4.2.3 on a production environment. I would appreciate if you can give me some information or references about how can I estimate the minimum ( <min-pool-size> ) and maximum ( <max-pool-size> ) pool size for the datasource.

Answer 1

It really depends on the load: how many users do access your application in a concurrent manner. And since people really seldom do things really concurrently it will be tough to guess.

Your best strategy might be to set the value pretty high and use a management console to observe connections. As far as I can recall the management console would show peaks, so take this value and set your max to a bigger value.

I would set min-pool-size to an value little less then average concurrent connection count or just leave it on default if you app doesn't show performance problems. Having ready to use connections speeds up the app but if you don't see performance problems why bother.

And of course you should take your database into accounts: how many concurrent connections does it allow, do you pay anything by concurrent connections or not.

Observe performance: does your database server runs on the same machine as JBoss? More possible connections mean more concurrent work for the database server means more CPU usage - this may also affect performance of the app server.

So again the best bet is a management console and a load test.