The Mariposa distributed database management system

Flexible copies: Copies can enhance data availability and provide faster query processing through parallel execution. However, the cost of maintaining the consistency of a large set of replicas can be prohibitive if conventional techniques (e.g., two-phase commit) are used. Mariposa provides a replica-management system that avoids the expensive synchronization requirements of conventional replica systems without sacrificing transaction serializability. Copies are at the granularity of fragments. The copy mechanism is discussed at greater length in [31. Flexible system management: The behavior of Mariposa sites is controlled by scripts written in an enhanced version of Tcl.