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

2 / 20

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

StartNewPG

CreateCluster

CreatePGC

Initialize

3 / 20

3. What is the point of the pg_global tablespace?

stores system catalog objects that are common to the whole cluster

stores user tables that are common to the whole cluster

stores temporary tables that are common to the whole cluster

stores WAL logs used for global replication

4 / 20

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

False

True

5 / 20

5. What is the purpose of the visibility map?

provides the data decryption key

shows a page to be vacuumed or frozen

shows referential relationships for tables

provides an audit trail for the database

6 / 20

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

GROW

BAKE

TOAST

BREAD

7 / 20

7. What is the default standard size for a fork file?

5MB

1GB

5GB

1MB

8 / 20

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

Egor Rogov

Dan Brown

Sam Altman

Paul Sammy

9 / 20

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

table map

visiblilty map

free space map

Main fork

10 / 20

10. System Catalog tables begin with which prefix?

sys_

cat_

pg_

dba_

11 / 20

11. Which fork contains the actual table data?

free space map

Main fork

visiblilty map

table map

12 / 20

12. Which of below are predefined schemas?

choose 3

information_schema

pg_schema

pg_temp

pg_toast

13 / 20

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

write-ahead log (WAL)

rollback segments (RBS)

undo segments (UNDO)

online redo logs (ORL)

14 / 20

14. Some System Catalog tables are common to all databases in the cluster?

True

False

15 / 20

15. If we create a new tablespace which directory will symbolic links be created from?

pg_tblspc

pg_symlinks

pg_tablespace

pg_tabspace

16 / 20

16. How many files or forks on disk will a 10Mb table with no index have?

17 / 20

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

True

False

18 / 20

18. Each Database has its own System Catalog?

True

False

19 / 20

19. What is the purpose of the template0 database?

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

No such database

Useful for creating development schemas

Useful for Postgres support Services to debug issues

20 / 20

20. TOAST tables reside in a seperate schema?

True

False

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 acronym used for the attributes that ensure Data consistency, integrity and durability?

SAFE

SOC2

HIPPA

ACID

2 / 10

2. non-repeatable read anomaly occurs when?

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 issue a rollback.

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.

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.

Use a single SQL operator

Apply explicit locks

Replace procedural code with declarative one.

4 / 10

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

choose 3

Serializable

Read Uncommitted

Repeatable Read

Read Committed

5 / 10

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

BEGIN ISOLATION LEVEL REPEATABLE READ;

SET ISO=REPEATABLE_READ;

ALTER SYSTEM SET ISO=REPEATABLE_READ;

CREATE EXTENSTION REPEATABLE_READ;

6 / 10

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

True

False

7 / 10

7. Which of the below are valid Isolations Levels?

choose 2

Serializable

Rollback Read

Random Scatter

Read Committed

8 / 10

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

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

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

9 / 10

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

False

True

10 / 10

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

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

False

True

2 / 10

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

choose 2

page header

free space

undo segment

flashback block

3 / 10

3. If a transaction is read only which kind of Transaction ID is it allocated?

heap XID

virtual XID

temporary XID

magic XID

4 / 10

4. CLOG files are stored in which directory?

PGDATA/pg_commit

PGDATA/pg_clog

PGDATA/clog

PGDATA/pg_xact

5 / 10

5. status of a subtransaction is written into CLOG?

True

False

6 / 10

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

True

False

7 / 10

7. Page free space can often become fragmented?

True

False

8 / 10

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

Each pointer uses 4 bytes

stored in PGDATA/itemptr directory

Each pointer uses 8 bytes

Also know as the pages table of contents

9 / 10

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

False

True

10 / 10

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

False

True

Your score is

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