Slots reserved for roles with the RESERVED_CONNECTION privilege (PG16+).
At a glance
| Property | Value |
|---|---|
| Parameter | reserved_connections |
| Category | Connections |
| Default | 0 |
| Value type | boolean / enum / numeric |
| Change scope | Restart required |
What it does
Reserves connection slots for non-superuser roles granted pg_use_reserved_connections, typically monitoring or HA tooling, so they can connect when normal slots are exhausted.
How to apply a change
Requires a full server restart (postmaster context). Set it in postgresql.conf and restart PostgreSQL.
Inspect the current value and source with SHOW reserved_connections; or SELECT name, setting, unit, context, source FROM pg_settings WHERE name = 'reserved_connections';.
Tuning guidance
Grant the predefined role to monitoring/HA users and reserve a few slots so health checks keep working during a connection storm.