conn-max-age setting has no affect??

[alexjfisher]

The conn-max-age setting is described in the PuppetDB docs as

The maximum time (in minutes), for a pooled connection to remain unused before it is closed off.

In the code it is used, (under some condition at least), to set the connection pool's IdleTimeout

puppetdb/src/puppetlabs/puppetdb/jdbc.clj

Lines 596 to 597 in 2c2efc9

	(when (and conn-max-age-ms conn-lifetime-ms (> conn-max-age-ms conn-lifetime-ms))
	(some->> conn-max-age-ms (.setIdleTimeout config)))

According to the HikariCP documentation on IdleTimeout

This setting only applies when minimumIdle is defined to be less than maximumPoolSize.

and since there is no mechanism in PuppetDB to set minimumIdle (the minimum number of idle connections that HikariCP tries to maintain in the pool), and this setting is not set to anything by PuppetDB and in HikariCP defaults to the same as maximumPoolSize

Default: same as maximumPoolSize

I suggest that conn-max-age is redundant as it does nothing. But maybe I've misread the code somewhere.

[alexjfisher]

oh dear, it does have an affect, but only because of a bug elsewhere. In converting minutes to milliseconds, two settings are swapped here...

puppetdb/src/puppetlabs/puppetdb/jdbc.clj

Lines 566 to 568 in 2c2efc9

	(let [conn-lifetime-ms (some-> conn-max-age pl-time/to-millis)
	conn-max-age-ms (some-> conn-lifetime pl-time/to-millis)
	config (HikariConfig.)]