Connection Pools Size vs. Number of concurrent requests

I have to develop a high scalable webservice, but the connection pool size (Oracle DB) is set to 50.

Having this size means that the number of开发者_开发技巧 concurrent request served will be max 50 ,otherwise the no new connections will be available right ?

But by configuration is possible for the Weblogic or Glassfish server to accept more then 50 requests simultaneously ?

I read that the server accepts the request which are 'queued' until a thread is handling them.

Regarding 'scalability' I have a question mark as well because the average DB calls take 1,2 sec. + the soap overhead...==> in a 2,3 sec response time on each call.

Can I estimate how many concurrent users the server will support (Weblogic or Glasfish 4gb) ?

Thank you

Having a maximum of 50 connections in the pool doesn't mean you can only handle 50 users at any one time. Each page request should generate queries that can interleave with each other: so while you can only have 50 queries running at any one time, should be able to handle many more page requests. This can be helped by making sure you only connect to the database for short periods.

The use of connection pools is primarily to avoid the cost of setting up new connections all the time (plus prepared statements are cached etc.), so the intention is to re-use them as frequently as possible.

When you say the average DB call takes 1.2 secs: if this a single query I think you want to look at the query or table indexes to reduce this time (otherwise I'm afraid you are going to get scalability problems no matter what), but if it is multiple queries then they should interleave with other requests quite happily.

As regards queuing: weblogic will queue queries, but you can set a timeout so the query is returned unfulfilled after a set time. You can then decide to try again or tell the user the system is busy and perhaps try again later.

When you are talking about web service, you need to keep a optimum balance between your connection pool and concurrent requests. For the concept you can refer: https://dzone.com/articles/optimum-database-connection-pool-size