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. Each Database has its own System Catalog?

True

False

2 / 20

2. What is the name of the directory that contains the files related to the Postgres cluster?

PGBASE

PGCORE

PGTIPS

PGDATA

3 / 20

3. What is the purpose of autovacuum?

Rebuilds indexes with b level greater than 2

Performs a backup of WAL logs

Removes stale data from tables and indexes

Deletes old logs and traces on disk

4 / 20

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

Initialize

StartNewPG

CreateCluster

CreatePGC

5 / 20

5. What 3 files/forks as a minimum make up a table on disk?

visiblilty map

Main fork

table map

free space map

6 / 20

6. What is another name for the postgres process?

postmanager

masterprocess

postmaster

aurora

7 / 20

7. Who is the Author of the Postgres 14 Internals book?

Sam Altman

Dan Brown

Paul Sammy

Egor Rogov

8 / 20

8. What is the purpose of the template0 database?

No such database

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

Useful for creating development schemas

Useful for Postgres support Services to debug issues

9 / 20

9. Which of below are predefined schemas?

choose 2

pg_catalog

system

postgres

public

10 / 20

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

Sysasm Catalog

System Catalog

Sys Catalog

Sysaux Catalog

11 / 20

11. What is the purpose of the visibility map?

shows referential relationships for tables

shows a page to be vacuumed or frozen

provides an audit trail for the database

provides the data decryption key

12 / 20

12. To be able to restore data consistency, Postgres maintains

undo segments (UNDO)

rollback segments (RBS)

write-ahead log (WAL)

online redo logs (ORL)

13 / 20

13. What is the name of the mechanism used to store a row bigger than a page size?

BAKE

BREAD

GROW

TOAST

14 / 20

14. Postgres uses a thread based process model?

True

False

15 / 20

15. Which of below are predefined schemas?

choose 3

pg_temp

information_schema

pg_toast

pg_schema

16 / 20

16. What is a schema?

A memory area used to cache data from LRU chains

Namespace that store all objects of a database

This is the same as a user in Postgres

The name used to refer to a super user account

17 / 20

17. What is the point of the pg_global tablespace?

stores WAL logs used for global replication

stores temporary tables that are common to the whole cluster

stores system catalog objects that are common to the whole cluster

stores user tables that are common to the whole cluster

18 / 20

18. Which of the below objects can be referred to as relations?

choose 3

triggers

tables

indexes

sequences

19 / 20

19. How does Postgres know which schema to use if not specified?

Directory Path

Schema Path

Search Path

Access Path

20 / 20

20. System Catalog tables begin with which prefix?

dba_

pg_

cat_

sys_

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. What is the default Isolation Level?

Serializable

Read Uncommitted

Read Committed

Repeatable Read

2 / 10

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

BEGIN ISOLATION LEVEL REPEATABLE READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

3 / 10

3. Snapshot isolation is preferred but increases the number of required locks?

True

False

4 / 10

4. Lost updates are forbidden by the standard at all isolation levels?

True

False

5 / 10

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

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

6 / 10

6. Which of the below are valid Isolations Levels?

choose 2

Serializable

Random Scatter

Read Committed

Rollback Read

7 / 10

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

False

True

8 / 10

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

True

False

9 / 10

9. Based on Snapshot Isolation use of MVCC which of the below are permitted?

choose 3

Repeatable Read

Read Uncommitted

Read Committed

Serializable

10 / 10

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

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

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 data direct from memory using pg_dirt

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. virtual IDs exist only in PGDATA/pg_vxid when not cached?

False

True

2 / 10

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

Each pointer uses 8 bytes

stored in PGDATA/itemptr directory

Also know as the pages table of contents

Each pointer uses 4 bytes

3 / 10

3. at any one time Postgres can have several versions of a row?

True

False

4 / 10

4. Rows of TOAST tables are handled in such a way that they are never update?

True

False

5 / 10

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

False

True

6 / 10

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

False

True

7 / 10

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

True

False

8 / 10

8. Tuples can also be referred to as columns?

True

False

9 / 10

9. Page free space can often become fragmented?

False

True

10 / 10

10. Postgres table physical data files are always cross compatible across platforms?

False

True

Your score is

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