Hi,
I use hibernate 3.1. My configuration of connection pool is following:



When I start two web clients from two terminal, hibernate's performace is very slow. But after I set the pool_size to be larger than 2, the performace improve a lot.

Does it mean that if I have millions of clients, then I have to the pool_size to be larger than one million to support millions of clients to concurrently acess DB using hibernate?

And what is the maximum pool_size that hibernate support?

Thanks.

Pool size of 1 means you only allow one client to access the resource at any one time. The result is all requests to the database will be serialised. Yes clients can be very slow and I would suggest yuou have atleast 2 for development (I tend to have 4).

Production pool size depends on your application. The pooling scales well so no you do not need 1 connection-per-client You will find if you test it. Pool of 2 will handle more than 2 clients and it scales further the greater the pool. If you have millions of clients and they don't have much concurrency then 10 might do or maybe 100 is necessary. Monitoring the application is the key to getting the sizing of resources correct.

The DB connection pooling is performed by support libraries. In youre case CP30 check their docs for any limits and sizing of pools eg min max and resource recovery semantics.