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 default standard size for a fork file?

1GB

5MB

5GB

1MB

2 / 20

2. Which fork contains the actual table data?

free space map

Main fork

table map

visiblilty map

3 / 20

3. What is another name for the postgres process?

postmanager

masterprocess

aurora

postmaster

4 / 20

4. System Catalog tables begin with which prefix?

cat_

dba_

sys_

pg_

5 / 20

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

online redo logs (ORL)

rollback segments (RBS)

undo segments (UNDO)

write-ahead log (WAL)

6 / 20

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

used space map

vacuum space map

free space map

wal space map

7 / 20

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

GROW

BAKE

TOAST

BREAD

8 / 20

8. What is the purpose of the template1 database?

database used for temporary tables

a template for all the other databases

regular database that you can use at your discretion

No such database

9 / 20

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

choose 2

pg_temp

pg_tablespace

pg_global

pg_default

10 / 20

10. What column in system catalogs servers as the Primary Key

oid

obj

oid#

obj#

11 / 20

11. The information_schema schema provides information on Postgres release notes?

True

False

12 / 20

12. What is the purpose of the template0 database?

Useful for Postgres support Services to debug issues

Useful for creating development schemas

No such database

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

13 / 20

13. A single Postgres Instance can server only one database?

True

False

14 / 20

14. What is a schema?

A memory area used to cache data from LRU chains

The name used to refer to a super user account

Namespace that store all objects of a database

This is the same as a user in Postgres

15 / 20

15. Which of below are predefined schemas?

choose 3

pg_schema

pg_toast

information_schema

pg_temp

16 / 20

16. What is the purpose of the visibility map?

shows referential relationships for tables

provides the data decryption key

provides an audit trail for the database

shows a page to be vacuumed or frozen

17 / 20

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

pg_system

pg_tables

pg_catalog

pg_class

18 / 20

18. Files are logically split into pages?

False

True

19 / 20

19. A schema can belong to more than one database?

True

False

20 / 20

20. Each tablespaces can only be assigned for use by one database

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

False

True

2 / 10

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

choose 3

Repeatable Read

Serializable

Read Uncommitted

Read Committed

3 / 10

3. What are some of database features we can use to avoid a non repeatable read?

Select more than 1 answer below:

Issues a rollback after the commit to satisfy repeatable read.

Apply explicit locks

Use a single SQL operator

Replace procedural code with declarative one.

4 / 10

4. 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;

5 / 10

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

True

False

6 / 10

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

False

True

7 / 10

7. Which of the below are valid Isolations Levels?

choose 2

Rollback Read

Serializable

Random Scatter

Read Committed

8 / 10

8. A phantom read anomaly occurs when?

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.

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 also queries this same data.

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

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

reading data direct from memory using pg_dirt

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

10 / 10

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

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. UPDATE can be regarded as which 2 separate operations?

INSERT

MERGE

COMMIT

DELETE

2 / 10

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

False

True

3 / 10

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

True

False

4 / 10

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

view

heap

clog

dump

5 / 10

5. Each page has a layer that usually consists of?

choose 2

page header

free space

undo segment

flashback block

6 / 10

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

Each pointer uses 4 bytes

Also know as the pages table of contents

Each pointer uses 8 bytes

stored in PGDATA/itemptr directory

7 / 10

7. indexes do not use row versioning?

True

False

8 / 10

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

False

True

9 / 10

9. Page free space can often become fragmented?

True

False

10 / 10

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

True

False

Your score is

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