AUTOCOMMIT is used to run the statement as autocommitted transaction.

NORMAL is the default commit order.

POST is used to designate post_sessions.

PRE is used to designate pre_sessions.

MULTI allows distributed transactions with best effort commit.

SINGLE disallows distributed transactions.

TWOPC is for distributed transactions with atomic commits.

UNSPECIFIED uses the transaction mode set by the VTGate flag 'transaction_mode'.

ExecuteBatchRequest is the payload to ExecuteBatch.

ExecuteBatchResponse is the returned value from ExecuteBatch.

ExecuteRequest is the payload to Execute.

ExecuteResponse is the returned value from Execute.

ResolveTransactionRequest is the payload to ResolveTransaction.

ResolveTransactionResponse is the returned value from Rollback.

Session objects are exchanged like cookies through various calls to VTGate.

StreamExecuteRequest is the payload to StreamExecute.

StreamExecuteResponse is the returned value from StreamExecute.

VStreamRequest is the payload for VStream.

VStreamResponse is streamed by VStream.

CommitOrder is used to designate which of the ShardSessions get used for transactions.

TransactionMode controls the execution of distributed transaction across multiple shards.