Sample Exam Questions

From the objective of OSS-DB Exam Gold
- Performance Tuning - Parameters related to performance

Sample Question

3.04

Select all processes for which performance is expected to improve by tuning work_mem.

  1. ORDER BY

  2. CREATE INDEX

  3. Merge Join

  4. VACUUM

  5. Automatic VACUUM

※This sample exam is different from those that appear in the actual OSS-DB Exam.
2025/06/02

Answer and Explanation

work_mem specifies the amount of memory used in sorting (internal sorting) and hashing processes.
Therefore, tuning work_mem is expected to improve the performance of "ORDER BY" and "MERGE JOIN" that involve sorting processes. On the other hand, the amount of memory used by "VACUUM" and "CREATE INDEX" is specified by maintenance_work_mem.
Also, the amount of memory used by "automatic VACUUM" (the amount of memory used by the autovacuum worker process) is specified by autovacuum_work_mem.
However, by default, maintenance_work_mem is set to be used.

Therefore, the correct answers are A and C.