PostgreSQL High Availability Certification

1. What is logical replication used for in PostgreSQL?

Replicating only table structure

Replicating specific tables to different databases

Replicating WAL files only

Replicating DDL statements only

2. In PostgreSQL, which replication type requires a publication and subscription setup?

Streaming replication

Logical replication

File-based replication

Backup-based replication

3. What does the recovery_min_apply_delay parameter accomplish?

Slows replication intentionally for protection

Speeds up failover

Compresses WAL records

Limits query concurrency

4. Which backup method provides the smallest backup size for large databases?

Full logical backup with pg_dump

Incremental physical backups

Complete base backup

Export to CSV

5. In a failover scenario, what is 'split-brain' in PostgreSQL clustering?

Two nodes both acting as primary simultaneously

Network latency between nodes

Replication lag exceeding timeout

Standby promoting to primary during network partition

6. What is the purpose of the max_wal_senders parameter?

Limits concurrent streaming replication connections

Sets WAL file size

Controls backup concurrency

Defines query timeout

7. Which PostgreSQL extension provides distributed transactions across multiple nodes?

Postgres_fdw

Pg_trgm

Pglogical

Uuid-ossp

8. In PostgreSQL, what is a 'hot standby'?

A standby that accepts read queries

A standby that cannot be queried

A backup server with no WAL

A standby limited to DDL only

9. What does the wal_level parameter set to 'replica' enable?

Only basic archiving

Streaming and file-based replication

Logical replication only

No replication support

10. Which command initiates a base backup in PostgreSQL?

Pg_basebackup

Pg_backup

Backup database

Pg_start_backup

11. Which PostgreSQL replication method provides the lowest latency for read-only replicas?

Streaming replication

Logical replication

File-based log shipping

Archive recovery

12. Which parameter controls the number of standby servers that must acknowledge writes?

Wal_level

Synchronous_commit

Synchronous_standby_names

Max_wal_senders

13. What is the maximum number of synchronous standbys that can acknowledge a transaction in PostgreSQL?

One only

Two only

Configurable via synchronous_standby_names

Unlimited

14. In a PostgreSQL cluster with Patroni, what is the role of the distributed consensus system?

To compress backups

To elect and manage the primary node

To execute queries in parallel

To optimize index usage

15. What does Recovery Target Timeline (PITR) allow you to do?

Set read-only replicas only

Restore database to a specific point in time

Limit query execution time

Encrypt WAL files

16. Which PostgreSQL high availability solution uses virtual IP failover?

Streaming replication alone

Patroni with etcd

Logical replication only

Pg_dump backups

17. What is synchronous replication in PostgreSQL?

Replication that occurs asynchronously without confirmation

Replication where primary waits for standby acknowledgment before commit

Replication using only file-based log shipping

Replication limited to local networks only

18. Which tool is commonly used for PostgreSQL backup automation and point-in-time recovery?

Pg_dump

PgBackRest

Pg_restore

Vacuumdb

19. In streaming replication, what does the standby server receive from the primary?

SQL statements

WAL records

Backup files

Query results

20. What is the primary purpose of WAL (Write-Ahead Logging) in PostgreSQL?

To cache query results

To ensure data durability and recovery

To optimize join operations

To compress database files

PostgreSQL Professional High Availability Quiz