I have recently migrated from C3P0 to HikariCP in a Spring and Hibernate based project and it was not as easy as I had imagined and here I am sharing my findings.
For Spring Boot see my answer here
I have the following setup
- Spring 4.3.8+
- Hiberante 4.3.8+
- Gradle 2.x
- PostgreSQL 9.5
Some of the below configs are similar to some of the answers above but, there are differences.
Gradle stuff
In order to pull in the right jars, I needed to pull in the following jars
//latest driver because *brettw* see https://github.com/pgjdbc/pgjdbc/pull/849
compile 'org.postgresql:postgresql:42.2.0'
compile('com.zaxxer:HikariCP:2.7.6') {
//they are pulled in separately elsewhere
exclude group: 'org.hibernate', module: 'hibernate-core'
}
// Recommended to use HikariCPConnectionProvider by Hibernate in 4.3.6+
compile('org.hibernate:hibernate-hikaricp:4.3.8.Final') {
//they are pulled in separately elsewhere, to avoid version conflicts
exclude group: 'org.hibernate', module: 'hibernate-core'
exclude group: 'com.zaxxer', module: 'HikariCP'
}
// Needed for HikariCP logging if you use log4j
compile('org.slf4j:slf4j-simple:1.7.25')
compile('org.slf4j:slf4j-log4j12:1.7.25') {
//log4j pulled in separately, exclude to avoid version conflict
exclude group: 'log4j', module: 'log4j'
}
Spring/Hibernate based configs
In order to get Spring & Hibernate to make use of Hikari Connection pool, you need to define the HikariDataSource and feed it into sessionFactory bean as shown below.
<!-- HikariCP Database bean -->
<bean id="dataSource" class="com.zaxxer.hikari.HikariDataSource" destroy-method="close">
<constructor-arg ref="hikariConfig" />
</bean>
<!-- HikariConfig config that is fed to above dataSource -->
<bean id="hikariConfig" class="com.zaxxer.hikari.HikariConfig">
<property name="poolName" value="SpringHikariPool" />
<property name="dataSourceClassName" value="org.postgresql.ds.PGSimpleDataSource" />
<property name="maximumPoolSize" value="20" />
<property name="idleTimeout" value="30000" />
<property name="dataSourceProperties">
<props>
<prop key="serverName">localhost</prop>
<prop key="portNumber">5432</prop>
<prop key="databaseName">dbname</prop>
<prop key="user">dbuser</prop>
<prop key="password">dbpassword</prop>
</props>
</property>
</bean>
<bean class="org.springframework.orm.hibernate4.LocalSessionFactoryBean" id="sessionFactory">
<!-- Your Hikari dataSource below -->
<property name="dataSource" ref="dataSource"/>
<!-- your other configs go here -->
<property name="hibernateProperties">
<props>
<prop key="hibernate.connection.provider_class">org.hibernate.hikaricp.internal.HikariCPConnectionProvider</prop>
<!-- Remaining props goes here -->
</props>
</property>
</bean>
Once the above are setup then, you need to add an entry to your log4j or logback and set the level to DEBUG to see Hikari Connection Pool start up.
Log4j1.2
<!-- Keep additivity=false to avoid duplicate lines -->
<logger additivity="false" name="com.zaxxer.hikari">
<level value="debug"/>
<!-- Your appenders goes here -->
</logger>
Logback
Via application.properties in Spring Boot
debug=true
logging.level.com.zaxxer.hikari.HikariConfig=DEBUG
Using logback.xml
<logger name="com.zaxxer.hikari" level="DEBUG" additivity="false">
<appender-ref ref="STDOUT" />
</logger>
With the above you should be all good to go! Obviously you need to customize the HikariCP pool configs in order to get the performance that it promises.
