Postgres Quiz Archive

You have 200 seconds to answer 20 Random questions so think fast!

You will need to score 80% or over to pass!

Created by

Paul Sammy

PostgreSQL 14 Internals Chapter 1

A quiz to test the knowledge of those reading and learning from Postgres 14 Internals book by Egor Rogov, covering topics in Chapter 1.

1 / 20

1. What is the point of the pg_global tablespace?

stores system catalog objects that are common to the whole cluster

stores temporary tables that are common to the whole cluster

stores WAL logs used for global replication

stores user tables that are common to the whole cluster

2 / 20

2. Which of below are predefined schemas?

choose 3

information_schema

pg_temp

pg_toast

pg_schema

3 / 20

3. Tablespaces are used to define physical data layout?

False

True

4 / 20

4. What is a schema?

Namespace that store all objects of a database

This is the same as a user in Postgres

A memory area used to cache data from LRU chains

The name used to refer to a super user account

5 / 20

5. What is the purpose of the postgres database?

a template for all the other database

restoring data from a logical backup or creating a database with a different encoding

regular database that you can use at your discretion

No such database

6 / 20

6. What is the purpose of the template1 database?

regular database that you can use at your discretion

No such database

a template for all the other databases

database used for temporary tables

7 / 20

7. What command is used to create the Postgres cluster?

CreatePGC

Initialize

StartNewPG

CreateCluster

8 / 20

8. Which fork is specific for unlogged tables?

free space map

Initialization fork

Main fork

visiblilty map

9 / 20

9. TOAST tables reside in a seperate schema?

True

False

10 / 20

10. Which fork keeps track of available space within pages?

vacuum space map

free space map

used space map

wal space map

11 / 20

11. What is the name of the catalog that stores metadata for all cluster objects?

Sys Catalog

System Catalog

Sysaux Catalog

Sysasm Catalog

12 / 20

12. Tablespaces can be used to segregate data based on performance needs?

False

True

13 / 20

13. What is the name of the 2 default tablespaces created after initialization?

choose 2

pg_tablespace

pg_temp

pg_global

pg_default

14 / 20

14. How many rows in a page does Postgres aim to have before considering TOAST?

15 / 20

15. What is the name of the system catalog table for relations?

pg_catalog

pg_tables

pg_system

pg_class

16 / 20

16. To understand each other, a client and a server must use one and the same interfacing protocol?

False

True

17 / 20

17. Postgres uses a thread based process model?

False

True

18 / 20

18. Which 3 databases exist directly after cluster initialization?

choose 3 options

postgres

template1

sysaux

template0

19 / 20

19. Postgres by default has built in connection pooling abilities?

True

False

20 / 20

20. The pg_default tablespace should never be used to create user tables?

False

True

Your score is

Created by

Paul Sammy

PostgreSQL 14 Internals Chapter 2

A quiz to test the knowledge of those reading and learning from Postgres 14 Internals book by Egor Rogov, covering topics in Chapter 2.

1 / 10

1. A phantom read anomaly occurs when?

A transactions inserts a null value into a not null columns and commits

The same transaction executes two identical queries returning a set of rows that satisfy a particular condition, while another transaction adds some other rows satisfying this condition and commits.

The same transactions issues a commit, then a rollback to restore data to its original value

The same transaction executes two identical queries returning a set of rows that satisfy a particular condition, while another transaction also queries this same data.

2 / 10

2. The more locks a transaction acquires, the better it is isolated from other transactions?

True

False

3 / 10

3. The SQL standard specifies three isolation levels?

False

True

4 / 10

4. Data Consistency is best handled at the application layer rather than at the database layer?

True

False

5 / 10

5. non-repeatable read anomaly occurs when?

A transaction reads one and the same row twice, another transaction modifies this row between these reads issue a rollback.

A transaction reads one and the same row once, another transaction modifies this row between these reads and commits the change.

A transaction reads one and the same row twice, another transaction modifies this row between these reads and commits the change.

A transaction reads one and the same row once and modifies this row and commits the change.

6 / 10

6. which of the below statements will start a transaction as Read Repeatable?

ALTER SYSTEM SET ISO=REPEATABLE_READ;

BEGIN ISOLATION LEVEL REPEATABLE READ;

CREATE EXTENSTION REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

7 / 10

7. Which parameters sets the database default isolation level?

transaction_isolation_level

default_isolation_level

default_transaction_isolation

active_transaction_isolation

8 / 10

8. Which isolation level in theory could mean an application does not have to consider isolation anomalies?

Repeatable Read

Read Committed

Read Uncommitted

Serializable

9 / 10

9. Which of the below would best describe a dirty read?

a session being able to see uncommited data altered by another session

a session being able to see commited data altered by another session

reading the data directly from file using a text editor such as vi or notepad

reading data direct from memory using pg_dirt

10 / 10

10. At any moment the database system can contain several versions of one and the same row?

False

True

Your score is

Created by

Paul Sammy

PostgreSQL 14 Internals Chapter 3

A quiz to test the knowledge of those reading and learning from Postgres 14 Internals book by Egor Rogov, covering topics in Chapter 3.

1 / 10

1. When a row is created, its xmin value is set to the transaction ID of which command?

CREATE

COMMIT

INSERT

DELETE

2 / 10

2. Which of the below are true about a Pages Item Pointer?

stored in PGDATA/itemptr directory

Each pointer uses 4 bytes

Each pointer uses 8 bytes

Also know as the pages table of contents

3 / 10

3. psql provides a special mode that allows you to continue a transaction after a failure?

False

True

4 / 10

4. The page Special Space is located at the start of the page with highest address

False

True

5 / 10

5. Indexes values also support multi versioning with several versions of an index value existing at any point in time?

True

False

6 / 10

6. Tuples can also be referred to as columns?

False

True

7 / 10

7. In Postgres, tables are often referred to as which of the below?

dump

heap

view

clog

8 / 10

8. a transaction containing a savepoint is will still be considered as only a single transaction?

True

False

9 / 10

9. The page header stores checksum and the sizes of the other parts of the page?

True

False

10 / 10

10. The page header is located in the highest address?

True

False

Your score is

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