Configuration of database pool

[AlexGacon]

Hello,

Is it possible to configure the different parameters of the DB pool for client connections? Like the min/max number of connections in the pool?

Regards
Alexandre

[bchapuis]

Yes, in the configuration file, the object representing a database can either be a string containing a JDBC URL or a Database object [1] representing a Hikari datasource [2]. In the latter case, the object can include all the properties defined in the Database class, which include amon other the minimumIdle and maximumPoolSize properties you are looking for.

In the config file the json object may look as follow:

{
  "jdbcUrl": "jdbc:postgresql://localhost:5432/mydb",
  "username": "user",
  "password": "password",
  "minimumIdle": 5,
  "maximumPoolSize": 20
}

[1] https://github.com/apache/incubator-baremaps/blob/main/baremaps-postgres/src/main/java/org/apache/baremaps/postgres/utils/Database.java
[2] https://github.com/brettwooldridge/HikariCP?tab=readme-ov-file#gear-configuration-knobs-baby

[AlexGacon]

Thanks a lot. It seems that it is not possible to configure a minimumPoolSize in Hikari datasources. Do you confirm that?

[bchapuis]

I think minimumIdle is what you are looking for.

minimumIdle: This property controls the minimum number of idle connections that HikariCP tries to maintain in the pool. If the idle connections dip below this value and total connections in the pool are less than maximumPoolSize, HikariCP will make a best effort to add additional connections quickly and efficiently. However, for maximum performance and responsiveness to spike demands, we recommend not setting this value and instead allowing HikariCP to act as a fixed size connection pool. Default: same as maximumPoolSize