A global transaction manager coordinates an atomic operation that spans multiple database nodes. Without authoritative coordination, ordinary transaction conflict management is insufficient when one application transaction uses more than one node. section 5.6
Treat the following as operational constraints:
- Using a single node for an atomic operation can remain within normal conflict-management techniques. section 5.6
- Using read replicas to offload work is valid, but not inside an application atomic operation forming a distributed transaction. section 5.6
- A global manager supplies authoritative coordination, but necessarily creates a performance bottleneck and can become a single point of failure. section 5.6
The tempting distributed transaction
An application performs one logical atomic operation across multiple database nodes, perhaps combining primary-node work with replica-backed work. The operation now requires strong consistency and isolation; without an authoritative global transaction manager, the distributed design inherits difficult coordination problems rather than ordinary single-node transaction behavior. section 5.6
