500 http sessions result in low database connection utilization

Question

We have an Alfresco server running on Tomcat6 and a look at the manager/html page tells us that there are approx. 500 active http session during an usual workday.

Is it normal/expected that this kind of load only utilizes one of the 8 open jdbc-connections? I would expect that there is a lot more load on the database as all the node metadata cannot already be in the ehcache.

My assumption would be that there is load on approx 30 DB connections.

Am I completely wrong on this?

Alfresco 4.0.2.9, Tomcat6, Java6, Window Server 2008R2, MSSQL

#alfresco-global.properties
db.pool.initial=30
db.pool.max=300
db.pool.idle=-1
hibernate.jdbc.fetch_size=150

Answer 1

For HTTP, 500 simultaneous connections is not really that many. Remember that HTTP 1.1 keeps the connection open after the current request or requests, to make subsequent requests faster, so these are not necessarily doing anything.

Rather than simultaneous connections, you should consider how many simultaneous requests there are - where the server is processing two requests simultaneously. Only then is there a reason to use more than one database connection.