connections and min-connections

These parameters control the maximum pool size and the minimum number of open connections to maintain.

Setting min-connections to a value greater than 0 keeps a warm-pool floor of established connections, enables unreachable-server fast-skip during request routing, and starts background maintenance probes (see min-connections-maintenance-timeout and min-connections-maintenance-retry-interval).

The default is 0, which disables all three. Set min-connections 1; (or higher) on production servers where fast failover and warm pools matter.

See Backend Load Balancing for further information.

Error: Setting min-connections greater than connections is a hard configuration error.

server "primary" {
    url "postgresql://radiator:secret@db.example.com:5432/radiator";
    connections 25;
    min-connections 2;
}

When every configured PostgreSQL pool appears full, Radiator returns a pool-exhausted error instead of intentionally queueing behind a saturated pool.