presto-raptor-legacy/src/main/java/io/prestosql/plugin/raptor/legacy/storage/ShardRecoveryManager.java/ShardRecoveryManager/shardNeedsRecovery
class ShardRecoveryManager:    private boolean shardNeedsRecovery(UUID shardUuid, long shardSize)
    {
        File storageFile = storageService.getStorageFile(shardUuid);
        return !storageFile.exists() || (storageFile.length() != shardSize);
    }