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6. Using Slick to access your database

§Play Slick Advanced Topics

§Connection Pool

With Slick 3.0 release, Slick starts and controls both a connection pool and a thread pool for optimal asynchronous execution of your database actions.

It’s worth noting that while Slick allows using a different connection pool than HikariCP (though, Slick currently only offers built-in support for HikariCP, and requires you to provide an implementation of JdbcDataSourceFactory if you want to use a different connection pool), Play Slick currently doesn’t allow using a different connection pool than HikariCP. If you find yourself needing this feature, please drop us a note on the playframework-dev mailing list.

Note: As stated in the Slick documentation, a reasonable default for the connection pool size is calculated from the thread pool size. Therefore, you should only need to tune numThreads and queueSize in most cases, for each of your database configuration.

Note: Changing the value of play.db.pool won’t affect what connection pool Slick is using. In fact, it’s worth noting that Play Slick disables both the play.api.db.DBModule and play.api.db.HikariCPModule Play modules, and it will let Slick be in control of creating and managing the connection pool.

§Thread Pool

With Slick 3.0 release, Slick starts and controls both a thread pool and a connection pool for optimal asynchronous execution of your database actions.

For optimal execution, you may need to tune the numThreads and queueSize parameters, for each of your database configuration. Refer to the Slick documentation for details.

Next: Play Slick FAQ