Block

The block is the fundamental object on the blockchain. Every 2s or so, a new block is created that may contain account transactions, update transactions or account creations.

Blocks are stored in the collection blocks in the db and has the following class:

Information about a block.

GRPC documentation: concordium.v2.BlockInfo

Attributes:

Name	Type	Description
arrive_time	Optional[CCD_TimeStamp]	Time the block was verified.
validator	Optional[int]	ID of the validator of this block.
hash	CCD_BlockHash	Hash of the block.
height	int	Absolute height of the block.
last_finalized_block	CCD_BlockHash	The last finalized block when this block was baked.
parent_block	CCD_BlockHash	The parent block hash.
receive_time	Optional[CCD_TimeStamp]	Time the block was received.
slot_number	Optional[int]	The slot number in which the block was baked.
slot_time	CCD_TimeStamp	Time of the slot in which the block was baked.
era_block_height	int	The height relative to genesis.
finalized	bool	Whether the block is finalized.
genesis_index	int	The genesis index for this block.
transaction_count	int	The number of transactions in the block.
transactions_energy_cost	int	The total energy cost of the transactions in the block.
transactions_size	int	The total size of the transactions in the block.
transaction_hashes	Optional[list[CCD_TransactionHash]]	The hashes of the transactions in the block.
state_hash	Optional[CCD_StateHash]	The state hash of the block.
protocol_version	Optional[str]	The protocol version of the block.
round	Optional[CCD_Round]	The round in which the block was created.
epoch	Optional[CCD_Epoch]	The epoch in which the block was created.

Source code in .venv/lib/python3.13/site-packages/ccdexplorer/grpc_client/CCD_Types/__init__.py

class CCD_BlockInfo(BaseModel):
    """Information about a block.

    GRPC documentation: [concordium.v2.BlockInfo](https://docs.concordium.com/concordium-grpc-api/#concordium.v2.BlockInfo)

    Attributes:
        arrive_time (Optional[CCD_TimeStamp]): Time the block was verified.
        validator (Optional[int]): ID of the validator of this block.
        hash (CCD_BlockHash): Hash of the block.
        height (int): Absolute height of the block.
        last_finalized_block (CCD_BlockHash): The last finalized block when this block was baked.
        parent_block (CCD_BlockHash): The parent block hash.
        receive_time (Optional[CCD_TimeStamp]): Time the block was received.
        slot_number (Optional[int]): The slot number in which the block was baked.
        slot_time (CCD_TimeStamp): Time of the slot in which the block was baked.
        era_block_height (int): The height relative to genesis.
        finalized (bool): Whether the block is finalized.
        genesis_index (int): The genesis index for this block.
        transaction_count (int): The number of transactions in the block.
        transactions_energy_cost (int): The total energy cost of the transactions in the block.
        transactions_size (int): The total size of the transactions in the block.
        transaction_hashes (Optional[list[CCD_TransactionHash]]): The hashes of the transactions in the block.
        state_hash (Optional[CCD_StateHash]): The state hash of the block.
        protocol_version (Optional[str]): The protocol version of the block.
        round (Optional[CCD_Round]): The round in which the block was created.
        epoch (Optional[CCD_Epoch]): The epoch in which the block was created.
    """

    arrive_time: Optional[CCD_TimeStamp] = None
    baker: Optional[int] = None
    hash: CCD_BlockHash
    height: int
    last_finalized_block: CCD_BlockHash
    parent_block: CCD_BlockHash
    receive_time: Optional[CCD_TimeStamp] = None
    slot_number: Optional[int] = None
    slot_time: CCD_TimeStamp
    era_block_height: int
    finalized: bool
    genesis_index: int
    transaction_count: int
    transactions_energy_cost: int
    transactions_size: int
    transaction_hashes: Optional[list[CCD_TransactionHash]] = None
    state_hash: Optional[CCD_StateHash] = None
    protocol_version: Optional[str] = None  # note this is not optional from the specification,
    # but this type is also used in retrieving blockInfo from MongoDB, where protocol_version
    # isn't stored for all blocks (currently).
    round: Optional[CCD_Round] = None
    epoch: Optional[CCD_Epoch] = None

Note that we have added the property transaction_hashes to the block class, to enable indexing transactions and blocks together. Finally, when a finalized block arrives, we store the block, the transactions and the special events.

How is a block stored in the system?

In the heartbeat service, all new finalized blocks are parsed and stored in the db.