How can I tell connection pool utilization in eclipselink

Question

I am working on a eclipseLink backed project, I want to use internal connection pool with EclipseLink, but I don't know how can I see it really working before it goes online.

I think I should enable logging for EclipseLink but I don't know what am I suppose to looking at in the log.

Another question is what is the best strategy to set connection pool size.

score 2 · Accepted Answer · answered Jan 23 '12 at 14:42

If you enable logging you should see when connections are acquired and released to the pool. At least on the latest version.

For the pool size, you want the size to be the same as your expected number of threads (threads, not clients). If you app server has a thread pool, a similar size should be used. Normally from 20-150 depending on your hardware, for big hardware you would use more.

Make the max and min sizes the same to avoid thrashing. Do not use a separate read connection pool, a combined read/write pool normally is more efficient (unless using JTA).

That helps a lot, I'll see if I can make it right, thanks man. — Lopakhin, Jan 24 '12 at 15:27

score 0 · Answer 2 · edited Jun 20 '20 at 09:12

Having a proper load generated use might be able to check an amount of connections in use in log output, which could be enabled with:

        <property name="eclipselink.logging.level" value="FINE" />
        <property name="eclipselink.logging.session" value="true" />
        <property name="eclipselink.logging.thread" value="true" />
        <property name="eclipselink.logging.timestamp" value="true" />
        <property name="eclipselink.logging.connection" value="true" />

Otherwise, you can check your connection pool's settings with your IDE's debugger:

Hope it helps.

score 0 · Answer 3 · answered May 21 '21 at 09:05

To get stats on the connection pool, you can use the following code:

    EntityManager entityManager = entityManagerFactory.createEntityManager();
    ServerSession serverSession = entityManager.unwrap(ServerSession.class);
    for (Entry<String, ConnectionPool> entry : serverSession.getConnectionPools().entrySet()) {
        System.out.println("Connection Pool Name: " + entry.getKey());
        System.out.println("Max Number Of Connections: " + entry.getValue().getMaxNumberOfConnections());
        System.out.println("Connections In Use: " + (entry.getValue().getMaxNumberOfConnections() - entry.getValue().getConnectionsAvailable().size()));
    }
    entityManager.close();

How can I tell connection pool utilization in eclipselink

3 Answers3