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Multiple Choice Questions - Hash Join

Multiple Choice Questions - Hash Join

1. Hash join is designed to handle large . . . . inputs.

A) sorted
B) unsorted

2. Hash joins are used for many types of set-matching operations such as . . . . .

A) intersection
B) inner join
C) left, right, and full outer join
D) both A & B
E) all of above

3. When an in-memory hash join is not possible, the Hash Warning is fired. The idea behind this event is that grace hash join and recursive hash joins are . . . . efficient and that the DBA should be aware of this.

A) more
B) equally
C) less
D) none of above

4. There are 3 different types of hash joins . . . . . .

A) in-memory, grace hash join and cursive hash join
B) in-memory, trace hash join and recursive hash join
C) out-memory, grace hash join and recursive hash join
D) in-memory, grace hash join and recursive hash join

5. Hash join requires an equality predicate.

A) True
B) False

6. There are three SQLTrace events that fire in response to hash spills, sort spills and exchange spills. They are ......

A) hashed warnings, sorted warnings and exchanged warnings
B) H warnings, S warnings and E warnings
C) hash warnings, sort warnings and exchange warnings
D) hash-spill warnings, sort-spill warnings and exchange-spill warnings

7. The term . . . . is sometimes used to describe grace hash joins or recursive hash joins.

A) Spill bailout
B) Join bailout
C) Spill Warning bailout
D) Hash bailout

8. Hash join performs its operations in 2 phases . . . . . .

A) initial phase and probe phase
B) init phase and probe phase
C) build phase and probe phase
D) build phase and problem phase

9. It is not always possible during optimization to determine which hash join is used. Therefore, SQL Server starts by using an in-memory hash join and gradually transitions to grace hash join, and recursive hash join, depending on the size of the build input.

A) True
B) False

10. A . . . . . . is a join method that used elements of both a simple in-memory hash and grace hash.

A) combined join
B) hybrid join
C) team join