1. In PostgreSQL, what is the purpose of the "pg_rewind" utility?
2. Which PostgreSQL extension provides support for handling hll (HyperLogLog) data types, useful for approximate distinct value counting?
3. Which PostgreSQL function is used to return the current transaction's unique identifier (XID)?
4. Which PostgreSQL extension allows you to create custom operators for use in SQL queries?
5. Which parameter in PostgreSQL controls the maximum number of simultaneously allowed background worker processes?
6. Which PostgreSQL extension provides support for data encryption at rest, transparently encrypting data stored on disk?
7. What is the purpose of the "pg_bouncer" utility in PostgreSQL?
8. What is the role of the "pg_snapshot" directory in PostgreSQL?
9. In PostgreSQL, which function is used to return the current user's name?
10. In PostgreSQL, which parameter controls the maximum size of the shared memory segment used by the database system?
11. What is the purpose of the "pg_depend" system catalog table in PostgreSQL?
12. Which parameter in PostgreSQL controls the maximum number of simultaneously allowed replication connections?
13. What is the purpose of the "pg_collation" system catalog table in PostgreSQL?
14. Which PostgreSQL extension provides support for handling binary large objects (BLOBs)?
15. In PostgreSQL, which statement is used to create a foreign key constraint?