Connection Pool Parameters

When a connection pool is used to access the database, database connections are established and then stored in the memory as objects during system running. When you need to access the database, no new connection is established. Instead, an existing idle connection is selected from the connection pool. After you finish accessing the database, the database does not disable the connection but puts it back into the connection pool. The connection can be used for the next access request.

pooler_maximum_idle_time

Parameter description: Specifies the maximum amount of time that the connections can remain idle in a pool before being removed. After that, the automatic connection clearing mechanism is triggered to reduce the number of connections on each node to the value of minimum_pool_size.

This parameter is a USERSET parameter. Set it based on instructions provided in Table 2 Methods for setting GUC parameters.

Value range: an integer ranging from 0 to INT_MAX. The smallest unit is s.

Default value: 10min

minimum_pool_size

Parameter description: Specifies the minimum number of remaining connections in the pool on each node after the automatic connection clearing is triggered. If this parameter is set to 0, the automatic connection clearing is disabled.

This parameter is a USERSET parameter. Set it based on instructions provided in Table 2 Methods for setting GUC parameters.

Value range: an integer ranging from 1 to 65535

Default value: 50

cache_connection

Parameter description: Specifies whether to reclaim the connections of a connection pool.

This parameter is a SIGHUP parameter. Set it based on instructions provided in Table 2 Methods for setting GUC parameters.

Value range: Boolean

• on indicates that the connections of a connection pool will be reclaimed.
• off indicates that the connections of a connection pool will not be reclaimed.

Default value: on