HikariCP poolName not read from config

[rickynils]

In HikariCPJdbcDataSource.forConfig, the pool name is not read from the config value (poolName, as documented on the HikariCP wiki), but instead picked up from the name argument (see https://github.com/slick/slick/blob/master/slick-hikaricp/src/main/scala/slick/jdbc/hikaricp/HikariCPJdbcDataSource.scala#L47).

Furthermore, the name argument is actually the path argument of the JdbcBackend.forConfig call (see https://github.com/slick/slick/blob/master/slick/src/main/scala/slick/jdbc/JdbcBackend.scala#L268), which is confusing since you get an empty pool name if you use a top-level config.

Is there any reasoning why the pool name is set like this and not simply picked up from the config?

[balagez]

This is actually a rather serious and annoying issue for play-slick users which manages Slick configuration itself so if poolName is not read from configuration there's no way for end users to set the pool name and all pools are created with the same db pool name. And since MBeans are looked up by poolName, without being able to configure the pool name it's impossible to monitor HikariCP connection pools if there are more than one in an application.

Example play-slick configuration based on the Play framework documentation:

slick.dbs.read.driver = "slick.driver.MySQLDriver$"
slick.dbs.read.db.driver = "com.mysql.jdbc.Driver"
slick.dbs.read.db.url = "jdbc:mysql://localhost:3306/dbname"
slick.dbs.read.db.poolName = "read"
slick.dbs.read.db.registerMbeans = true

slick.dbs.write.driver = "slick.driver.MySQLDriver$"
slick.dbs.read.db.driver = "com.mysql.jdbc.Driver"
slick.dbs.read.db.url = "jdbc:mysql://localhost:3306/dbname"
slick.dbs.read.db.poolName = "write"
slick.dbs.read.db.registerMbeans = true

And relevant parts of the HikariCP debug log:

2016-02-10 18:51:03,846 [DEBUG] com.zaxxer.hikari.HikariConfig - HikariCP pool db configuration:
...
2016-02-10 18:51:03,859 [DEBUG] com.zaxxer.hikari.HikariConfig - poolName........................db
2016-02-10 18:51:03,859 [DEBUG] com.zaxxer.hikari.HikariConfig - readOnly........................false
2016-02-10 18:51:03,859 [DEBUG] com.zaxxer.hikari.HikariConfig - registerMbeans..................true
...
2016-02-10 18:51:03,862 [INFO] com.zaxxer.hikari.HikariDataSource - HikariCP pool db is starting.
2016-02-10 18:51:03,912 [DEBUG] com.zaxxer.hikari.HikariConfig - HikariCP pool db configuration:
...
2016-02-10 18:51:03,921 [DEBUG] com.zaxxer.hikari.HikariConfig - poolName........................db
2016-02-10 18:51:03,921 [DEBUG] com.zaxxer.hikari.HikariConfig - readOnly........................false
2016-02-10 18:51:03,921 [DEBUG] com.zaxxer.hikari.HikariConfig - registerMbeans..................true
...
2016-02-10 18:51:03,922 [INFO] com.zaxxer.hikari.HikariDataSource - HikariCP pool db is starting.
2016-02-10 18:51:03,923 [ERROR] com.zaxxer.hikari.pool.HikariMBeanElf - You cannot use the same pool name for separate pool instances.

[balagez]

I think the commit 4569c52 didn't take into consideration that JMX and logging actually relies on configurable pool names.

I found no workaround for this issue because the pool is created and MBeans are registered in the pool constructor the same time the datasource is created and HikariCP provides no way to access the pool instance and register MBeans manually after the datasource is created. So having manually configurable pool names is a requirement for JMX monitoring.