Transactions

NuoDB supports truly ACID transactions.

However, there are a few differences with other RDBMS:

  • In addition to the standard SQL isolation levels, NuoDB also supports an additional isolation mode, CONSISTENT_READ, (implementing a form of Multi-Version Concurrency Control or MVCC).

    • CONSISTENT_READ is the default transaction isolation level.

    • READ_UNCOMMITTED, REPEATABLE_READ and SERIALIZABLE are all implemented using CONSISTENT_READ.

  • All DDL instructions (CREATE TABLE, ALTER TABLE …​) are properly transactional.

    • DDL changes cannot be seen until the transaction commits and do not happen if the transaction is rolled back.