Tuning the Presto or MashZone Repository Connection Pool

In addition to basic connection configuration, you can configure the connection pools for the Presto Repository or the MashZone Repository. In many cases, you need to tune this configuration to optimize your Presto environments.

Note:

For a complete list of connection properties, see TomEE Datasource Properties.

To tune the connection pool, you update properties in the <Resource> element for the Presto or MashZone repository in the presto-install/apache-tomee-jaxrs/conf/tomee.xml file and then restart Presto to apply these changes.

initialSize	The initial number of connections to create when the pool starts up. This defaults to 0.
maxActive	The maximum number of connections that can be allocated at one time. This defaults to 20. Set this to -1 to remove all limits.
maxWaitTime	The maximum number of milliseconds that the pool will wait when no connections are available before failing. Defaults to -1 which is an indefinite wait.

maxIdle	The maximum number of connections that can be idle without connections being released. Defaults to 20. Set this to -1 to prevent any connections being released.
minIdle	The minimum number of idle connections that can exist before new connections are added to the pool. This defaults to 0, indicating no new connections should be created.
testWhileIdle	Whether connections should be tested when idle. If this is enabled, idle connections are tested using the Validation query. See Move the Presto and MashZone Repositories to a Robust Database Solution for more information on validation queries.
timeBetweenEvictionRuns	The number of milliseconds between tests of idle connections. This defaults to -1, which prevents all idle connection testing.
numTestsPerEvictionRun	The number of connections to test during any idle connection test run.
minEvictableIdleTime	The minimum number of milliseconds that a connection can be idle before being tested for eviction. Default is 3 minutes.