Question: Suppose relation r is stored partitioned and indexed on A, and s is stored partitioned and indexed on B. Consider the query: a. Give a

Suppose relation r is stored partitioned and indexed on A, and s is stored partitioned and indexed on B. Consider the query:

a. Give a parallel query plan using the exchange operator, for computing the subtree of the query involving only the select and join operators.

b. Now extend the above to compute the aggregate. Make sure to use preaggregation to minimize the data transfer.

c. Skew during aggregation is a serious problem. Explain how preaggregation as above can also significantly reduce the effect of skew during aggregation.

r.CY count(s.D) (4>5(r)) r.B=s.BS)

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