Validators take turns driving the process of accepting transactions. When a validator acts as a leader, it proposes transactions, both those directly submitted to it by clients and those indirectly submitted through other validators, to the other validators. All validators execute the transactions and form an authenticated data structure that contains the new ledger history. The validators vote on the authenticator for this data structure as part of the consensus protocol
As part of committing a transaction Ti at version i, the consensus protocol outputs a signature on the full state of the database at version i — including its entire history — to authenticate responses to queries from clients." ... "The Libra protocol uses an account-based data model to encode the ledger state.
"Executing a transaction T i produces a new ledger state S i as well as the execution status code, gas usage, and event list.