Distributed Database Question Bank with Answers 05

Question:

When and why is fragmentation favorable in a distributed database?

Answer:

Fragmentation will speed up data access and updates when a query or an update only affects a single fragment. Queries and updates to several fragments can be parallelized.

Fragmentation is favorable when a database table is geographically distributed on some key. Local updates and all kinds of searches will be speeded up. A disadvantage is that global updates require synchronization (2-phase commit) to guarantee atomicity. Furthermore, if the connections are unreliable the availability for global data access is low.

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