Questions 

1. What's the difference between logical and streaming replication?
2. Why do PostgreSQL security updates often require minimal downtime?
3. What's the name of the main process of the PostgreSQL server?
4. When installing PostgreSQL on Linux, you don't need to provide a password; what's the reason for this?
5. What is Greenplum?
6. What's meant by a physical backup and what utilities does PostgreSQL provide to achieve this?
7. A developer destroyed some data by mistake on a database cluster. Do you think the administrator can recover PostgreSQL to a specific point in time? 
8. We briefly mentioned the CLUSTER and REINDEX statements. Use the psql tool's client meta-command to get the syntax for the CLUSTER and INDEX statements.
9. Why is the psql tool very handy in shell scripting?