In a range selection on a range-partitioned attribute, it is possible that only one disk may need to be accessed. Describe the benefits and drawbacks of this property.
Answer to relevant QuestionsWhat factors could result in skew when a relation is partitioned on one of its attributes by:a. Hash partitioningb. Range partitioningIn each case, what can be done to reduce the skew?Describe a good way to parallelize each of the following.a. The difference operationb. Aggregation by the count operationc. Aggregation by the count distinct operationd. Aggregation by the avg operatione. Left outer join, if ...a. What are the three broad levels at which a database system can be tuned to improve performance?b. Give two examples of how tuning can be done, for each of the levels.For each of the SQL aggregate functions sum, count, min and max, show how to compute the aggregate value on a multiset S1 ∪ S2, given the aggregate values on multisets S1 and S2. Based on the above, give expressions to ...Suppose half of all the transactions in a clothes shop purchase jeans, and one third of all transactions in the shop purchase T-shirts. Suppose also that half of the transactions that purchase jeans also purchase T-shirts. ...
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