Blockchain Developer - Hyperledger Fabric CBDH Updated Exam

Membership services provide identity, privacy, and confidentiality to the network. Abstraction of an architecture for membership operations.

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Endorsing Peer Endorser peer Peers can be marked as Endorser peer (i.e. Endorsing peer). Upon receiving the “transaction invocation request” from the Client application the Endorser peer Validates the transaction. Check certificate details and roles of the requester. Executes the Chaincode (Smart Contract) and simulates the outcome of the transaction. But it does not update the ledger. At the end of the above two tasks the Endorser may approve to disapprove the transaction. As only the Endorser node executes the Chaincode (Smart Contract) so there is no necessity to install Chaincode in each and every node of the network which increases the scalability of the network.

The ledger system in Hyperledger fabric uses levelDB. By definition, LevelDB allows concurrent writers to safely insert data into the database by providing internal synchronization. LevelDB uses very coarse-grained synchronization which forces all writes to proceed in an ordered, first-come-first-served basis, effectively reduces throughput to a single thread. State database options include LevelDB and CouchDB. LevelDB is the default key-value state database embedded in the peer process. CouchDB is an optional alternative external state database. Like the LevelDB key-value store, CouchDB can store any binary data that is modeled in chaincode (CouchDB attachment functionality is used internally for non-JSON binary data). But as a JSON document store, CouchDB additionally enables rich query against the chaincode data, when chaincode values (e.g. assets) are modeled as JSON data