Multiple choice technology databases

Why is searching for large-table full-table scans critical to SQL tuning?

  1. They indicate an optimized execution plan.

  2. They may be able to be tuned to use an index

  3. The full-table scan should be normalized from the database design

  4. A full-table scan is always sub-optimal.
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B Correct answer
Explanation

Full-table scans on large tables consume significant I/O and CPU resources. Identifying them allows you to investigate whether adding appropriate indexes could improve performance. However, scans aren't always sub-optimal - for small tables or when most rows are needed, a scan may be the best access path.

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