数据库连接池安全与资源控制（泄漏检测-超时-上限）最佳实践

一、参数与校验type PoolOpt = { max: number; idleTimeoutMs: number; acquireTimeoutMs: number } function validPool(opt: PoolOpt): boolean { return opt.max > 0 && opt.max <= 1000 && opt.idleTimeoutMs >= 1000 && opt.acquireTimeoutMs >= 100 } 二、封装与泄漏检测class LeakDetector { inUse = new Set<string>() start(id: string) { this.inUse.add(id) } end(id: string) { this.inUse.delete(id) } count(): number { return this.inUse.size } } type Conn = { id: string; query: (sql: string, params?: any[]) => Promise<any>; close: () => Promise<void> } class DbPool { opt: PoolOpt leak = new LeakDetector() queue: Conn[] = [] constructor(opt: PoolOpt) { this.opt = opt } async acquire(): Promise<Conn> { const start = Date.now() while (Date.now() - start < this.opt.acquireTimeoutMs) { if (this.queue.length > 0) { const c = this.queue.pop() as Conn this.leak.start(c.id) return c } await new Promise(r => setTimeout(r, 10)) } throw new Error('acquire_timeout') } async release(c: Conn) { this.leak.end(c.id); this.queue.push(c) } } 三、慢查询与审计type Audit = { id: string; sql: string; durationMs: number; timestamp: string } function nowIso(): string { return new Date().toISOString() } async function timedQuery(c: Conn, sql: string, params: any[], thresholdMs: number): Promise<{ rows: any[]; audit?: Audit }> { const t0 = Date.now() const rows = await c.query(sql, params) const dt = Date.now() - t0 const audit = dt >= thresholdMs ? { id: c.id, sql, durationMs: dt, timestamp: nowIso() } : undefined return { rows, audit } } 四、断路与回退class Circuit { fail = 0; open = false threshold: number constructor(threshold: number) { this.threshold = threshold } trip() { this.fail++; if (this.fail >= this.threshold) this.open = true } reset() { this.fail = 0; this.open = false } } async function guardedQuery(pool: DbPool, circuit: Circuit, sql: string, params: any[]): Promise<any> { if (circuit.open) throw new Error('circuit_open') const c = await pool.acquire() try { const r = await timedQuery(c, sql, params, 200); circuit.reset(); return r } catch (e) { circuit.trip(); throw e } finally { await pool.release(c) } } 五、验收清单最大连接、空闲与获取超时参数校验通过；队列可用且超时返回错误。泄漏检测在获取与释放时记录；慢查询审计包含SQL与耗时。断路器在失败达到阈值时打开并回退；恢复后重置计数。