PostgreSQL Objective Questions & Answers for Practitioners Set-2
1. Which PostgreSQL isolation level provides the highest level of isolation but may lead to more concurrency issues?
Explanation: The SERIALIZABLE isolation level in PostgreSQL provides the highest level of isolation, ensuring that transactions are executed in a way that is equivalent to serial execution. However, this level of isolation may lead to more concurrency issues, such as serialization failures.
2. What is the purpose of the pg_repack extension in PostgreSQL?
Explanation: The pg_repack extension in PostgreSQL is used to repack and compress large tables, helping to save storage space and improve performance.
3. What is the primary benefit of using the SERIAL data type in PostgreSQL for creating auto-incrementing columns?
Explanation: The SERIAL data type in PostgreSQL is used to create auto-incrementing columns, automatically generating sequential values for the column, which is especially useful for primary keys.
4. In PostgreSQL, what is the role of the pg_stat_activity view?
Explanation: The pg_stat_activity view in PostgreSQL is used to view the list of currently active connections to the database, providing information about the running queries and other details.
5. Which statement is used to remove a table and its associated data from a PostgreSQL database?
Explanation: The DROP TABLE statement in PostgreSQL is used to remove a table and its associated data from a database.
6. What is the purpose of the pg_basebackup utility in PostgreSQL?
Explanation: The pg_basebackup utility in PostgreSQL is used to create a full binary backup of a PostgreSQL database cluster, including all data and configuration files.
7. Which PostgreSQL feature allows you to define custom data types?
Explanation: PostgreSQL extensions allow you to define custom data types, functions, operators, and other database objects, making it a powerful feature for extending PostgreSQL's capabilities.
8. Which statement is used to change the ownership of a PostgreSQL database object, such as a table?
Explanation: The ALTER TABLE ... OWNER TO statement in PostgreSQL is used to change the ownership of a table to a specific user or role.
9. What is the purpose of the pg_stat_replication view in PostgreSQL?
Explanation: The pg_stat_replication view in PostgreSQL is used to view the replication status of standby servers in a replication setup.
10. Which PostgreSQL configuration parameter controls the maximum number of concurrent connections to the database server?
Explanation: The max_connections configuration parameter in PostgreSQL controls the maximum number of concurrent connections that can be made to the database server.
11. In PostgreSQL, what is the role of the pg_stat_bgwriter view?
Explanation: The pg_stat_bgwriter view in PostgreSQL is used to monitor the status of background writer processes, which are responsible for writing dirty pages to disk.
12. What is the purpose of the pg_bouncer tool in PostgreSQL?
Explanation: The pg_bouncer tool in PostgreSQL is used to manage connection pooling, helping to efficiently manage database connections and improve server performance.
13. Which PostgreSQL command is used to rename a table?
Explanation: The ALTER TABLE ... RENAME TO statement in PostgreSQL is used to rename a table.
14. In PostgreSQL, what is the purpose of the pg_locks view?
Explanation: The pg_locks view in PostgreSQL is used to view the current lock status of database objects, providing information about locks held by transactions.
15. What is the purpose of the pg_wal directory in PostgreSQL?
Explanation: The pg_wal directory in PostgreSQL is used to store archived transaction log files, which are essential for point-in-time recovery and replication.
Related content
Rate Your Experience
: 89
: 1