Multiple choice technology databases

What is one significant aspect about a Cover Query?

  1. All columns required by the query are available via the Primary index.

  2. All columns required by the query are available via a Join Index.

  3. All columns required by the query are available via the Hash Index

  4. The PE covers the query by looking into cache to see if the same query has been run in the last 240 minutes. If it has been cached the PE doesn't have to generate steps for the AMPs.
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B Correct answer
Explanation

A Cover Query is optimized to retrieve all required columns directly from a Join Index without accessing the base table. Join Indexes pre-join and store frequently queried column combinations, allowing the optimizer to satisfy queries entirely from the index structure. This eliminates expensive joins and dramatically improves performance.

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