CBDH CBDH Consensus & Transaction Validation 2

Question 1

What is MVCC (Multi-Version Concurrency Control) in the context of Hyperledger Fabric?

Accepted Answer

A conflict detection mechanism that invalidates transactions whose read data changed since simulation

Answer

A method for encrypting ledger blocks

Answer

A gossip protocol variant

Answer

A certificate revocation strategy

Question 2

In Hyperledger Fabric, what is the 'read set' in a transaction's read-write set?

Accepted Answer

The set of keys and their versions read during chaincode simulation

Answer

The list of chaincode functions called

Answer

The list of peers that endorsed the transaction

Answer

The output events emitted by chaincode

Question 3

What does 'phantom read' protection in Hyperledger Fabric ensure?

Accepted Answer

A transaction is invalidated if the range query result would differ at commit time versus simulation time

Answer

Encrypted reads are decrypted correctly

Answer

All peers read from the same block simultaneously

Answer

CouchDB queries return consistent results

Question 4

Which ordering service consensus mode in Fabric requires an external Apache Kafka and ZooKeeper cluster?

Accepted Answer

Kafka-based ordering

Answer

Solo

Answer

Raft

Answer

BFT ordering

Question 5

What is the 'Solo' ordering service in Hyperledger Fabric primarily used for?

Accepted Answer

Development and testing environments only

Answer

Production deployments with single-org channels

Answer

High-throughput enterprise ordering

Answer

Byzantine fault tolerant consensus

Question 6

In a Raft ordering service, what role does the 'leader' node play?

Accepted Answer

Receives client transactions and replicates them to follower orderers before cutting blocks

Answer

Validates endorsement signatures

Answer

Issues identity certificates to peers

Answer

Manages the gossip protocol for peers