Idempotence for database transactions

A method, machine, and computer-readable medium is provided for managing transactional sets of commands sent from a client to a server for execution. A server receives, from a client in a second session, a request that identifies a set of commands that were sent by the client in a first session. The set of commands comprises one or more transactions. The server determines that at least one transaction of the one or more transactions in the set of commands has not committed. Based at least in part on determining that the at least one transaction of the one or more transactions has not committed, the server blocks, from the second session, completion of the at least one transaction in the first session to prevent committing of the at least one transaction in the first session.