Blockchain based hierarchical data storage

A computer-implemented system, comprising:

• one or more computers, and
• one or more computer memory devices interoperably coupled with the one or more computers and having tangible, non-transitory, machine-readable media storing one or more instructions that, when executed by the one or more computers, perform operations comprising:
• determining, based on a blockchain stored in a database that includes multiple levels of storage, a level of storage of the multiple levels of storage that meets a data migration condition as a target level of storage, wherein state data of the blockchain are stored as state Merkle trees in data worksheets of the multiple levels of storage;
• generating, for the target level of storage, an empty data worksheet in response to determining that the target level of storage meets the data migration condition;
• storing at least a portion of a first state Merkle tree corresponding to a newly created block of the blockchain to the empty data worksheet;
• migrating a second state Merkle tree corresponding to a target block stored in a data worksheet to the empty data worksheet, wherein the target block has a largest block number among block numbers of blocks corresponding to the state Merkle trees stored in the target level of storage;
• and
• after migrating the second state Merkle tree corresponding to the target block, migrating the state Merkle trees stored in the data worksheet to a lower level of storage than the target level of storage, wherein the lower level of storage has lower storage cost.

A non-transitory, computer-readable medium storing one or more instructions executable by a computer system to perform operations comprising:

• determining, based on a blockchain stored in a database that includes multiple levels of storage, a level of storage of the multiple levels of storage that meets a data migration condition as a target level of storage, wherein state data of the blockchain are stored as state Merkle trees in data worksheets of the multiple levels of storage;
• generating, for the target level of storage, an empty data worksheet in response to determining that the target level of storage meets the data migration condition;
• storing at least a portion of a first state Merkle tree corresponding to a newly created block of the blockchain to the empty data worksheet;
• migrating a second state Merkle tree corresponding to a target block stored in a data worksheet to the empty data worksheet, wherein the target block has a largest block number among block numbers of blocks corresponding to the state Merkle trees stored in the target level of storage;
• and
• after migrating the second state Merkle tree corresponding to the target block, migrating the state Merkle trees stored in the data worksheet to a lower level of storage than the target level of storage, wherein the lower level of storage has lower storage cost.