Question

why set 10 in hibernate config file for connection pooling ? size = 1 is built in size.why need to increase size ?

<?xml version='1.0' encoding='utf-8'?>

    <!DOCTYPE hibernate-configuration PUBLIC
            "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
            "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
    
    <hibernate-configuration>
    
        <session-factory>
         ....
    
           <property name="connection.pool_size">10</property>
    
         ....
        </session-factory>
    
    </hibernate-configuration>

Answer 1

From the Hibernate API Docs.

Hibernate’s own connection pooling algorithm is, however, quite rudimentary. It is intended to help you get started and is not intended for use in a production system, or even for performance testing. You should use a third party pool for best performance and stability. Just replace the hibernate.connection.pool_size property with connection pool specific settings. This will turn off Hibernate’s internal pool. For example, you might like to use c3p0.

connection.pool_size indicates the maximum number of pooled connections. So it is better to keep it at a logical count. It depends on your application and DB how much it can handle. 10 is a reasonable count that will typically used as it is sufficient for most cases.