Method downloadMetaInParallel

ethstorage/storage_manager.go:414–453

(ctx context.Context, from, to, batchSize uint64)

}

func (s *StorageManager) downloadMetaInParallel(ctx context.Context, from, to, batchSize uint64) error {
	var wg sync.WaitGroup
	taskNum := uint64(MetaDownloadThread)

	// We don't need to download in parallel if the meta amount is small
	if to-from < uint64(taskNum)*batchSize {
		return s.downloadMetaInRange(ctx, from, to, batchSize, 0)
	}

	chanRes := make(chan error, taskNum)
	defer close(chanRes)

	rangeSize := (to - from) / uint64(taskNum)
	for taskIdx := uint64(0); taskIdx < taskNum; taskIdx++ {
		rangeStart := taskIdx * rangeSize
		rangeEnd := (taskIdx + 1) * rangeSize
		if taskIdx == taskNum-1 {
			rangeEnd = to
		}
		wg.Add(1)

		go func(start, end, taskId uint64, out chan<- error) {
			defer wg.Done()
			err := s.downloadMetaInRange(ctx, start, end, batchSize, taskId)

			chanRes <- err
		}(rangeStart, rangeEnd, taskIdx, chanRes)
	}

	wg.Wait()

	for i := uint64(0); i < taskNum; i++ {
		res := <-chanRes
		if res != nil {
			return res
		}
	}

	return nil
}

func (s *StorageManager) downloadMetaInRange(ctx context.Context, from, to, batchSize, taskId uint64) error {
	rangeStart := from