Parallel indices: 

a. Secondary indices in a centralized database store the record identifier. A global secondary index too could potentially store a partition number holding the record, and a record identifier within the partition. Why would this be a bad idea?

b. Global secondary indices are implemented in a way similar to local secondary indices that are used when records are stored in a B+-tree file organization. Explain the similarities between the two scenarios that result in a similar implementation of the secondary indices.