Struct PoolSizingAdvisor 

pub struct PoolSizingAdvisor { /* private fields */ }

Connection pool pressure monitor with scaling recommendations.

Call PoolSizingAdvisor::evaluate with current PoolMetrics to get a PoolSizingRecommendation, or call PoolSizingAdvisor::start to launch a background task that polls the adapter automatically.

Note: This monitor operates in recommendation mode only. The pool is not resized at runtime — act on fraiseql_pool_tuning_* events by adjusting max_connections in fraiseql.toml and restarting the server.

Implementations

impl PoolSizingAdvisor

pub const fn new(config: PoolPressureMonitorConfig) -> Self

Create a new pool pressure monitor with the given configuration.

pub fn evaluate(&self, metrics: &PoolMetrics) -> PoolSizingRecommendation

Evaluate current pool metrics and return a scaling decision.

This method is pure computation — no I/O, no async. It updates internal sample counters so consecutive calls with the same condition accumulate toward samples_before_action.

pub fn adjustments_total(&self) -> u64

Total number of resize operations applied or recommended.

pub fn recommended_size(&self) -> u32

Current recommended pool size (0 = not yet sampled).

pub fn start<A: DatabaseAdapter + 'static>( self: Arc<Self>, adapter: Arc<A>, resize_fn: Option<Arc<dyn Fn(usize) + Send + Sync>>, ) -> JoinHandle<()>

Start a background polling task.

The task samples adapter.pool_metrics() every tuning_interval_ms milliseconds and calls Self::evaluate. If resize_fn is provided, it is called with the new pool size whenever a resize is decided. If resize_fn is None, the tuner operates in recommendation mode: it updates recommended_size and logs a warning without modifying the pool.

Returns a tokio::task::JoinHandle that can be aborted for shutdown.