Concept:A parallel database system processes tasks using multiple processors and is typically designed with a shared-nothing architecture.
Explanation:• In a parallel database, several processors work together on the same database operations to improve speed and efficiency.
• The common architectural model for this setup is the “shared-nothing” architecture, where each processor has its own private memory, disk, and processing unit, and they communicate through a fast interconnection network.
• This architecture helps reduce contention and allows the system to scale horizontally.
• Option A (communication cost and problems cannot be ignored) applies more to distributed databases, where machines are geographically separated.
• Option B (machines far from each other) also describes a distributed database, not a parallel database.
• Option C (machines physically close) is a physical description of parallel databases, but the architectural characteristic specifically tested here is the use of shared-nothing architecture.
• Therefore, the most accurate architectural feature of a parallel database is the shared-nothing model.
Answer:D. It is usually associated with shared-nothing architecture.