Struct PoolMetrics 

pub struct PoolMetrics {
    pub acquire_count: u64,
    pub acquire_failed_count: u64,
    pub acquire_wait_time: Duration,
    pub release_count: u64,
    pub connection_created_count: u64,
    pub connection_closed_count: u64,
}

连接池累计统计指标（Prometheus 风格）

所有字段均为池生命周期内的累计值（不会随获取/归还重置）， 由 Pool::pool_metrics() 返回。基于无锁 AtomicU64 计数， 对 acquire/release 热路径的影响可忽略（单条原子指令）。 serde 序列化支持：观测层导出（Pool::metrics_snapshot_json，v4.7.0 观测闭环）。

Fields

acquire_count: u64

累计成功获取连接次数

acquire_failed_count: u64

累计获取连接失败次数（超时 / 连接创建失败 / 池已关闭 / 断路器或限流拒绝）

acquire_wait_time: Duration

累计等待获取连接的时长（池满时阻塞等待的累计时间）

release_count: u64

累计归还连接次数

connection_created_count: u64

累计创建连接数（含 prewarm / warmup / acquire 新建）

connection_closed_count: u64

累计关闭连接数（含过期回收 / 失效 / 池关闭）

Implementations

impl PoolMetrics

pub fn average_acquire_wait_time(&self) -> Duration

平均获取等待时长（无成功获取时为 0）

pub fn connection_reuse_rate(&self) -> f64

连接复用率：已复用连接次数占总获取次数的比例

复用次数 = acquire_count - connection_created_count（每次新建连接不算复用）。

• acquire_count == 0 时返回 0.0（数据不足）
• connection_created_count > acquire_count 时返回 0.0（防御性）

Trait Implementations

impl Clone for PoolMetrics

fn clone(&self) -> PoolMetrics

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for PoolMetrics

impl Debug for PoolMetrics

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for PoolMetrics

fn default() -> PoolMetrics

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for PoolMetrics

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for PoolMetrics

impl PartialEq for PoolMetrics

fn eq(&self, other: &PoolMetrics) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl Serialize for PoolMetrics

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for PoolMetrics