Fabric 上链数据大小限制

  Fabric上链数据的大小与区块的最大值和区块能够写入的最大交易数是有关联的，以Fabric2.0版本为例，截取官方fabric-samples/first-network/configtx.yaml部分内容：

################################################################################
#
#   SECTION: Orderer
#
#   - This section defines the values to encode into a config transaction or
#   genesis block for orderer related parameters
#
################################################################################
Orderer: &OrdererDefaults

    # Orderer Type: The orderer implementation to start
    OrdererType: etcdraft

    Addresses:
        - orderer.example.com:7050

    # Batch Timeout: The amount of time to wait before creating a batch
    BatchTimeout: 2s

    # Batch Size: Controls the number of messages batched into a block
    BatchSize:

        # Max Message Count: The maximum number of messages to permit in a batch
        MaxMessageCount: 10

        # Absolute Max Bytes: The absolute maximum number of bytes allowed for
        # the serialized messages in a batch.
        AbsoluteMaxBytes: 99 MB

        # Preferred Max Bytes: The preferred maximum number of bytes allowed for
        # the serialized messages in a batch. A message larger than the preferred
        # max bytes will result in a batch larger than preferred max bytes.
        PreferredMaxBytes: 512 KB

    # Organizations is the list of orgs which are defined as participants on
    # the orderer side of the network
    Organizations:

    # Policies defines the set of policies at this level of the config tree
    # For Orderer policies, their canonical path is
    #   /Channel/Orderer/
    Policies:
        Readers:
            Type: ImplicitMeta
            Rule: "ANY Readers"
        Writers:
            Type: ImplicitMeta
            Rule: "ANY Writers"
        Admins:
            Type: ImplicitMeta
            Rule: "MAJORITY Admins"
        # BlockValidation specifies what signatures must be included in the block
        # from the orderer for the peer to validate it.
        BlockValidation:
            Type: ImplicitMeta
            Rule: "ANY Writers"

  没有区块会大于 AbsoluteMaxBytes的大小或有比 MaxMessageCount更多的交易在区块中。
  BatchTimeout决定了自一个交易到达后，在分割区块前，等待另外交易的时间量。降低这个值会改善延迟，但降低太多将因为不允许区块填充到其最大容量而减少吞吐量。
  PreferredMaxBytes设置了首选的区块大小。