Let me first say that the PBXT storage engine has some great people behind it. At the users conference last April, I had a chance to meet Paul McCullagh, who created PBXT, and some of the people who work on it. They are dedicated individuals who are creating something unique.Like the InnoDB storage engine, which is backed by the Innobase company, PBXT has a company that backs it, Primebase Technologies. This means that if needed, support can be got from the company that created the product. For enterprise companies this might be important.The basics characteristics of PBXT:\tMVCC: Multi-version concurrency control, enables reading without locking.\tTransactional: Support for "BEGIN", "COMMIT" and "ROLLBACK" and recovery on startup.\tACID compliant: Atomic, Consistent, Isolated, Durable (once committed, changes cannot be lost).\tRow-level locking: updates use row-level locking, allowing for maximum concurrency.\tDeadlock detection: immediate notification if client processes are deadlocked.\tReferential Integrity: foreign-key support.\tWrite-once: PBXT avoids double-writes by using a log-based architecture.Much of this is the same as for the other transactional storage engines, so I won't spend time on them. What sets PBXT apart from other storage engines is the write-once characteristic. It is worth understanding.