fix(db): add MaxConnLifetimeJitter to prevent synchronized conn expiration storms

internal/infra/db/postgres.go

@@ -12,7 +12,8 @@ import (
 const (
 	defaultMaxConns              = 20
 	defaultMinConns              = 2
-	defaultMaxConnLifetime = time.Hour
+	defaultMaxConnLifetime       = time.Hour                   // 单连接最大寿命，到点后回收重建
+	defaultMaxConnLifetimeJitter = defaultMaxConnLifetime / 10 // 在寿命基础上叠加 0~6 分钟随机抖动，防同步重建 storm
 	defaultPingTimeout           = 5 * time.Second
 	defaultHealthTimeout         = time.Second
 )
@@ -31,6 +32,7 @@ func NewPool(ctx context.Context, dsn string) (*Pool, error) {
 	cfg.MaxConns = defaultMaxConns
 	cfg.MinConns = defaultMinConns
 	cfg.MaxConnLifetime = defaultMaxConnLifetime
+	cfg.MaxConnLifetimeJitter = defaultMaxConnLifetimeJitter
 
 	pool, err := pgxpool.NewWithConfig(ctx, cfg)
 	if err != nil {