Method listInstancesBatched

database/sql/instances.go:477–524

listInstancesBatched is a helper function that retrieves instances in batches and converts them to params.Instance. It accepts a query modifier function to customize the base query (e.g., add WHERE clauses).

(queryModifier func(*gorm.DB) *gorm.DB)

// and converts them to params.Instance. It accepts a query modifier function
// to customize the base query (e.g., add WHERE clauses).
func (s *sqlDatabase) listInstancesBatched(queryModifier func(*gorm.DB) *gorm.DB) ([]params.Instance, error) {
	ret := []params.Instance{}
	err := s.conn.Transaction(func(tx *gorm.DB) error {
		batchSize := 1000
		offset := 0
		for {
			var batch []Instance

			// Start with base query and apply modifier
			query := tx.Limit(batchSize).Offset(offset).
				Preload("Pool").
				Preload("ScaleSet").
				Preload("Job")

			if queryModifier != nil {
				query = queryModifier(query)
			}

			q := query.Find(&batch)
			if q.Error != nil {
				return fmt.Errorf("error fetching instances: %w", q.Error)
			}
			if len(batch) == 0 {
				break
			}

			// Pre-grow slice to avoid multiple small reallocations
			if cap(ret) < len(ret)+len(batch) {
				newCap := max(len(ret)+len(batch), cap(ret)*2)
				newRet := make([]params.Instance, len(ret), newCap)
				copy(newRet, ret)
				ret = newRet
			}

			// Convert directly into result slice
			for _, instance := range batch {
				converted, err := s.sqlToParamsInstance(instance)
				if err != nil {
					return fmt.Errorf("error converting instance: %w", err)
				}
				ret = append(ret, converted)
			}
			offset += len(batch)
		}
		return nil
	})
	return ret, err
}

func (s *sqlDatabase) ListPoolInstances(_ context.Context, poolID string, outdatedOnly bool) ([]params.Instance, error) {
	u, err := uuid.Parse(poolID)