Global consistency constraints considered harmful for heterogeneous database systems

Argues that heterogeneous databases and serializable schedules are contradictory terms in practice. This implies that mechanisms that guarantee fully serializable schedules are an overkill. Much simpler and unrestricted mechanisms can provide the correctness that is needed in heterogeneous systems. Serializable schedules are desirable because they enforce database consistency constraints. In a multi-computer system there are two types of consistency constraints: local and global. Global constraints are the ones that cause problems, as enforcing them requires synchronization among sites